TAMBJAMINES AND B RING FUNCTIONALIZED PRODIGININES

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of the earlier filing date of U.S. Provisional

Application No. 62,155,383, filed April 30, 2015, which is incorporated by reference in its entirety herein.

FIELD

This disclosure concerns tambjamines and B-ring functionalized prodiginines, as well as methods of synthesizing and using the disclosed compounds.

ACKNOWLEDGMENT OF GOVERNMENT SUPPORT

This invention was made with government support under Grant No. R01GM077147 awarded by the National Institutes of Health. The government has certain rights in the invention.

BACKGROUND

Malaria is a global parasitic infectious disease caused by Plasmodium parasites, among which Plasmodium falciparum (Pf) is the most dangerous one, with the highest rates of complications and mortality. It has been estimated that 584,000 people died from this disease in

2013, and the burden is heaviest in the African region, where an estimated 90% of all malaria deaths occur, and in children aged under 5 years, who account for 78% of all deaths. ¹ On the heels of the global spread of chloroquine-resistant P. falciparum (CQ ^R /), resistance has also quickly developed to a variety of quinoline analogues, to antifolates, to inhibitors of electron transport, and perhaps most ominously, now to artemisinin. ² Therefore, novel medicinal agents are urgently needed to overcome the emergence and spread of resistance.

Prodiginines (PGs, la-c), tambjamines (TAs, 2a-b), and modified prodiginines

(streptorubin B (3a), metacycloprodiginine (3b) and marineosins (4 and 5)) belong to a family of pyrrolylpyrromethene (PPM) alkaloids (FIG. 1) derived from bacterial and marine sources. ³ ' ⁴

These structurally distinctive natural products can be envisioned to arise via a bifurcated process from a common precursor, 4-methoxy-2,2'-bipyrrole-5-carboxaldehyde (MBC; 6, FIG. 1) and the corresponding alkylpyrrole and/or alkylamine. ^{4 7} The natural and synthetic PPM products are undergoing intense scrutiny in the medicinal chemistry because of both their wide range of biological activities and modes of action (antimicrobial, ⁸ immunosuppressive, ⁹ antitumor, ^8a_b ' ¹⁰ anticancer, ³⁰ ' ¹¹ antimalarial ⁴ ' ^{12 14} transmembrane anion transport, ^{l le g} ' ¹⁵ and DNA intercalation ¹⁶ ). Certain PGs and TAs have also been observed to bind duplex DNA and can cleave this biomolecule in the presence of Cu(II). ^3a ' ¹⁷ Some of these compounds have shown clinical potential, and in particular, PG analogue, GX 15-070 has completed phase II clinical trials for the treatment of small cell lung cancer and is engaged in multiple clinical trials for the treatment of other cancer conditions. ¹⁸

SUMMARY

Embodiments of tambjamine and prodiginine analogues are disclosed. In some embodiments, the compound has a chemical structure according to Formula I or Formula IIA, or is a pharmaceutically acceptable salt thereof

wherein:

(i) R ¹ is H, lower alkyl, or lower alkoxy; R ² is H, lower alkyl, lower alkoxy, halo, or pyrrolyl; R ³ is aryl or heteroaryl; and R ⁴ is cycloalkyl; or

(ii) R ^l -R ³ independently are lower alkyl, and R ⁴ is alkyl or cycloalkyl.

In some embodiments, R ¹ is H, lower alkyl, or lower alkoxy; R ² is H lower alkyl, lower

alkoxy, halo, or pyrrolyl; R ³ is pyrrolyl; and R ⁴ is cycloalkyl. R ³ may be where R ⁵ -R ⁷ independently are H or lower alkyl. In an independent embodiment, R ¹ is lower alkyl or lower alkoxy, and R ² is H, lower alkyl, or lower alkoxy. In another independent embodiment, R ¹ is Ci-C ₄ alkoxy or Ci-C ₄ alkyl, R ² is H or Ci-C ₄ alkyl, and R ⁴ is C5-C12 cycloalkyl. For example, R ¹ may be methoxy or methyl, and R ² may be H, methyl, or ethyl. In any or all of the foregoing embodiments, R ⁵ -R ⁷ may be H, or R ⁵ and R ⁶ may be H and R ⁷ may be lower alkyl. In some embodiments, R^-R ³ independently are lower alkyl, and R ⁴ is alkyl or cycloalkyl. In certain embodiments, R ^l -R ³ independently are lower alkyl, such as Ci-C ₄ alkyl, and R ⁴ is C5-C12 alkyl or C5-C12 cycloalkyl.

In any or all of the above embodiments, R ⁴ may be bridged cycloalkyl. In any or all of the above embodiments, R ⁴ may be cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, or adamantyl.

Exemplary compounds include:

Embodiments of a pharmaceutical composition include a compound as disclosed herein and at least one pharmaceutically acceptable carrier. The pharmaceutical composition may further include a second therapeutic agent, such as an antimalarial agent.

Embodiments of a method for inhibiting a Plasmodium species include contacting the Plasmodium species with an effective amount of a compound as disclosed herein or

pharmaceutically acceptable salt thereof. Contacting the Plasmodium species may comprise contacting a cell infected with the Plasmodium species with the effective amount of the compound or pharmaceutically acceptable salt thereof.

Embodiments of a method for treating malaria comprise administering to a subject having malaria or at risk of developing malaria a therapeutically effective amount of (i) a compound or pharmaceutically acceptable salt thereof according to any one of claims 1-13 or (ii) a pharmaceutical composition comprising the compound or pharmaceutically acceptable salt thereof and at least one pharmaceutically acceptable carrier. The method may further include administering to the subject a second therapeutic agent, such as an antimalarial agent. In some embodiments, the subject is administered a pharmaceutical composition comprising (i) the compound or pharmaceutically acceptable salt thereof, (ii) the second therapeutic agent, and (iii) at least one pharmaceutically acceptable carrier. The subject may be separately administered, concurrently or sequentially in any order, (i) the compound or pharmaceutically acceptable salt thereof and (ii) the second therapeutic agent.

The foregoing and other objects, features, and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows structures of natural pyrrolylpyrromethene (PPM) alkaloids 1-5 and their common biosynthetic precursor 6.

FIG. 2 shows structures of precursors 6-20 for synthesis of B-ring functionalized prodiginines (PGs) and tambjamines (TAs).

FIG. 3 shows structures of precursors 21-43 for synthesis of A- and B-ring

functionalized PGs and TAs.

FIG. 4 shows structures of potential substrates 80-84 for synthesis of PGs.

FIG. 5 is a bar graph showing the structure-activity relationship of TAs containing various cycloalkyl groups and in vitro antimalarial activity against Plasmodium falciparum strains D6, Dd2, and 7G8.

DETAILED DESCRIPTION

Embodiments of tambjamines and B-ring functionalized prodiginines are disclosed. Methods of synthesizing and using the disclosed compounds are also disclosed.

I. Terms and Definitions

The following explanations of terms and abbreviations are provided to better describe the present disclosure and to guide those of ordinary skill in the art in the practice of the present disclosure. As used herein, "comprising" means "including" and the singular forms "a" or "an" or "the" include plural references unless the context clearly dictates otherwise. The term "or" refers to a single element of stated alternative elements or a combination of two or more elements, unless the context clearly indicates otherwise.

Unless explained otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, suitable methods and materials are described below. The materials, methods, and examples are illustrative only and not intended to be limiting. Other features of the disclosure are apparent from the following detailed description and the claims.

Unless otherwise indicated, all numbers expressing quantities of components, molecular weights, percentages, temperatures, times, and so forth, as used in the specification or claims are to be understood as being modified by the term "about." Accordingly, unless otherwise indicated, implicitly or explicitly, the numerical parameters set forth are approximations that may depend on the desired properties sought and/or limits of detection under standard test conditions/methods. When directly and explicitly distinguishing embodiments from discussed prior art, the embodiment numbers are not approximates unless the word "about" is recited.

In order to facilitate review of the various embodiments of the disclosure, the following explanations of specific terms are provided:

ABBREVIATIONS USED: CQ ^R , chloroquine-resistant P. falciparum; CQ ^R , chloroquine-resistant; CQ ^S , chloroquine-sensitive; Pf Plasmodium falciparum; PGs, prodiginines: TAs, tambjamines; PPM, pyrrolylpyrromethene; SAR, structure-activity relationship; CQ, chloroquine; MQ, mefloquine; IC50; half maximal inhibitory concentration; nM, nanomolar; MDR, multidrug-resistant; ADMET, adsorption, distribution, metabolism, excretion and toxicity; ED50, median effective dose; NRD, non-recrudescence dose (the amount of drug needed for 100% protection of malaria-infected mice until day 28).

Administering: Administration by any route, for example oral, topical, intravenous, intraperitoneal, intramuscular, intralesional, intranasal, or subcutaneous administration, release from a suppository, or the implantation of a slow-release device (e.g., a mini-osmotic pump) to the subject. "Parenteral" administration is by any route other than through the alimentary tract and includes intravascular administration directly into a blood vessel, for example by intravenous or intra- arterial administration.

Alkoxy: A radical (or substituent) having the structure -OR, where R is a substituted or unsubstituted alkyl. Methoxy (-OCH3) is an exemplary alkoxy group. In a substituted alkoxy, R is alkyl substituted with a non-interfering substituent. The term lower alkoxy means the chain includes 1-10 carbon atoms. Aliphatic: A substantially hydrocarbon-based compound, or a radical thereof (e.g., C ₆ Hi3, for a hexane radical), including alkanes, alkenes, alkynes, including cyclic versions thereof, and further including straight- and branched-chain arrangements, and all stereo and position isomers as well. Unless expressly stated otherwise, an aliphatic group contains from one to twenty-five carbon atoms; for example, from one to fifteen, from one to ten, from one to six, or from one to four carbon atoms. The term "lower aliphatic" refers to an aliphatic group containing from one to ten carbon atoms. Unless expressly referred to as an "unsubstituted aliphatic," an aliphatic group can either be unsubstituted or substituted.

Alkyl: A hydrocarbon group having a saturated carbon chain. The chain may be branched or unbranched. The term lower alkyl means the chain includes 1-10 carbon atoms. Unless otherwise specified, an alkyl group may be substituted or unsubstituted.

Aryl: A monovalent aromatic carbocyclic group of, unless specified otherwise, from 6 to 15 carbon atoms having a single ring (e.g., phenyl) or multiple condensed rings in which at least one ring is aromatic (e.g., quinoline, indole, benzodioxole, and the like), provided that the point of attachment is through an atom of an aromatic portion of the aryl group and the aromatic portion at the point of attachment contains only carbons in the aromatic ring. If any aromatic ring portion contains a heteroatom, the group is a heteroaryl and not an aryl. Aryl groups are monocyclic, bicyclic, tricyclic or tetracyclic. Unless otherwise specified, an aryl group may be substituted or unsubstituted.

Arylalkyl: An acyclic alkyl group in which one of the hydrogen atoms bonded to a carbon atom, typically a terminal or sp ³ carbon atom, is replaced with an aryl group. Typical arylalkyl groups include, but are not limited to, benzyl, 2-phenylethan- l-yl, naphthylmethyl, 2- naphthylethan-l-yl, naphthobenzyl, 2-naphthophenylethan- l-yl and the like.

Cycloalkyl: A saturated monovalent cyclic hydrocarbon radical of three to seven ring carbons, e.g., cyclopentyl, cyclohexyl, cycloheptyl and the like. The cycloalkyl may be monocyclic or bridged (polycyclic). Exemplary bridged cycloalkyl groups include adamantyl (tricyclo[3.3.1.1]decyl) and norbornyl (bicycle[2.2.1]heptyl). Unless otherwise specified, a cycloalkyl group may be substituted or unsubstituted.

Effective amount/dose or therapeutically effective amount/dose: An amount sufficient to provide a beneficial, or therapeutic, effect to a subject or a given percentage of subjects.

Heteroaryl: A monovalent monocyclic or bicyclic aromatic radical of 5 to 10 ring atoms with each ring containing one, two, or three ring heteroatoms selected from N, O, or S, the remaining ring atoms being C. The aromatic radical is optionally fused to a phenyl or an optionally substituted heteroaryl ring or it is optionally substituted independently with one or more substituents, such as one or two substituents selected from alkyl, haloalkyl, heteroalkyl, aliphatic, hetero aliphatic, alkoxy, halo, cyano, nitro, aryl, optionally substituted heteroaryl, amino, monosubstituted amino, disubstituted amino, hydroxyamino, -OR (where R is hydrogen, haloalkyl, or optionally substituted phenyl), -S(0) _n R (where n is an integer from 0 to 2 and R is alkyl, haloalkyl, optionally substituted phenyl, amino, mono or disubstituted amino), -C(0)R (where R is hydrogen, alkyl, haloalkyl or optionally substituted phenyl), -COOR (where R is hydrogen, alkyl or optionally substituted phenyl), -C(0)N(R')R" (where R' and R" are independently selected from hydrogen, alkyl, haloalkyl, or optionally substituted phenyl). In specific examples, the term heteroaryl includes, but is not limited to pyridyl, pyrrolyl, thiophene, pyrazolyl, thiazolyl, imidazolyl, pyrimidinyl, thiadiazolyl, indolyl, carbazolyl, azaindolyl, benzofuranyl, benzimidazolyl, benzthiazolyl, quinoxalinyl, benzotriazolyl, benzisoxazolyl, purinyl, quinolinyl, isoquinolinyl, benzopyranyl, and derivatives thereof. Unless otherwise specified, a heteroaryl group may be substituted or unsubstituted.

Pharmaceutically acceptable carrier: Conventional pharmaceutically acceptable carriers are useful for practicing the methods and forming the compositions disclosed herein. Remington 's Pharmaceutical Sciences, by E. W. Martin, Mack Publishing Co., Easton, PA, 15th Edition, 1975, describes examples of compositions and formulations suitable for pharmaceutical delivery of the compounds herein disclosed. In general, the nature of the carrier will depend on the particular mode of administration being employed. For instance, parenteral formulations usually include injectable fluids that include pharmaceutically and physiologically acceptable fluids such as water, physiological saline, balanced salt solutions, aqueous dextrose, glycerol or the like as a vehicle. For solid compositions (for example, powder, pill, tablet, or capsule forms), conventional non-toxic solid carriers can include, for example, pharmaceutical grades of mannitol, lactose, starch, or magnesium stearate. In addition to biologically-neutral carriers, pharmaceutical compositions to be administered can contain minor amounts of non-toxic auxiliary substances, such as wetting or emulsifying agents, preservatives, and pH buffering agents and the like, for example sodium acetate or sorbitan monolaurate. In some examples, the pharmaceutically acceptable carrier is a non-naturally occurring or synthetic carrier. The carrier also can be formulated in a unit-dosage form that carries a preselected therapeutic dosage of the active agent, for example in a pill, vial, bottle, or syringe. Pharmaceutically acceptable salt: A biologically compatible salt of a compound that can be used as a drug, which salts are derived from a variety of organic and inorganic counter ions well known in the art and include, by way of example only, sodium, potassium, calcium, magnesium, ammonium, tetraalkylammonium, and the like; and when the molecule contains a basic functionality, salts of organic or inorganic acids, such as hydrochloride, hydrobromide, tartrate, mesylate, acetate, maleate, oxalate, and the like. In some examples disclosed herein, the pharmaceutically acceptable salt is an acid addition salt. Pharmaceutically acceptable acid addition salts are those salts that retain the biological effectiveness of the free bases while formed by acid partners that are not biologically or otherwise undesirable, e.g., inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like, as well as organic acids such as acetic acid, trifluoroacetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid,

ethanesulfonic acid, /?-toluenesulfonic acid, salicylic acid and the like.

Pyrrolyl: As used herein, the term "pyrrolyl" refers to a pyrrole radical having the formula:

where each R independently is H or lower alkyl.

Subject: An animal or human subjected to a treatment, observation or experiment. Substituted: A fundamental compound, such as an aryl or aliphatic compound, or a radical thereof, having coupled thereto, typically in place of a hydrogen atom, a second substituent. For example, substituted aryl compounds or substituents may have an aliphatic group coupled to the closed ring of the aryl base, such as with toluene. Again solely by way of example and without limitation, a hydrocarbon may have a substituent bonded thereto, such as one or more halogens, an aryl group, a cyclic group, a heteroaryl group or a heterocyclic group.

Therapeutic agent or active agent: An agent that provides a beneficial, or therapeutic, effect to a subject or a given percentage of subjects.

Treating or treatment: With respect to disease, either term includes (1) preventing the disease, e.g., causing the clinical symptoms of the disease not to develop in a human or non- human animal that may be exposed to or predisposed to the disease but does not yet experience or display symptoms of the disease, (2) inhibiting the disease, e.g., arresting the development of the disease or its clinical symptoms, or (3) relieving the disease, e.g., causing regression of the disease or its clinical symptoms.

II. Introduction

Natural PGs la, and 3a were isolated from Streptomyces coelicolor M511 and 3b from

S. longisporus ruber (FIG. I). ¹⁹ These natural PGs exhibited great potency with very low IC50 values against P. falciparum strains, a potency only slightly more than chloroquine (CQ). ¹³ The natural PG 3b provided an excellent in vivo efficacy against multidrug-resistant P. yoelii in mice. It was curative in this model at 100 mg/kg/day, and three of four mice were cured. These data provided the first demonstration of oral effectiveness of PGs. ¹³ The modified prodiginines, marineosins (5), and their pathway intermediates 23-hydroxyundecyl-prodiginine (lb), 23- ketoundecylprodiginine (lc), and premarinesoin (4) were isolated through heterologous expression of the entire mar gene cluster and/or gene replacement mutants in a heterologous host, S. venezuelae. ⁴ Of these, the compound 4 antimalarial activity compares favorably with the most potent naturally occurring PGs and CQ.

Antimalarial activity studies have shown that a terminal nonalkylated pyrrole (ring- A), and 3,5-dialkyl substitutions on the other terminal alkylated pyrrole (ring-C) of a natural tripyrrole PGs core structure provide potent antimalarial activity. ^{13 14} A number of the synthetic PGs were effective at lower concentrations (IC50 = 0.9-16.0 nM) against P. falciparum strains and their potency was more than the natural PGs and CQ.

With a few exceptions, ⁹ ^ ^{1 la_b} ' ^{l lg} ' ¹⁴ there have been no reports of a comprehensive series of TAs and B-ring functionalized PGs being prepared and evaluated for biological activities. Novel TAs and B-ring functionalized PGs have been synthesized as disclosed herein for enhanced antimalarial activity and reduced toxicity. New methods for the synthesis of various 2,2'-bipyrrole-5-carboxaldehydes have been developed, ²⁰ and utilized in the generation of TAs and B-ring functionalized PGs. The results show TAs with impressive in vitro potency and low toxicity and demonstrate that a tripyrrole structure is not required for activity. Furthermore, evidence of in vivo efficacy with TAs, including curative efficacy in mice after oral

administration is reported.

III. Compounds and Pharmaceutical Compositions

Embodiments of the disclosed tambjamine and prodiginine analogues have a a chemical structure according to Formula I or Formula II, or a pharmaceutically acceptable salt thereof

With respect to Formula I:

(i) R ¹ is H, lower alkyl or lower alkoxy; R ² is H, lower alkyl, lower alkoxy, halo, or pyrrolyl, or R ¹ and R ² together with the carbon atoms to which they are attached form an aliphatic ring; R ³ is aryl or heteroaryl; and R ⁴ is cycloalkyl; or

(ii) R ^l -R ³ independently are lower alkyl, and R ⁴ is alkyl or cycloalkyl.

In some embodiments, R ¹ and R ² are as previously defined, R ⁴ is cycloalkyl, such as C ₃ - Ci2 cycloalkyl, and R ³ is pyrrolyl having a structure

wherein R ⁵ -R ⁷ independently are hydrogen or lower alkyl. The cycloalkyl may an unsubstituted C ₃ -Ci2 cycloalkyl, and the cycloalkyl may be bridged or unbridged.

In one embodiment, R ¹ is lower alkyl (e.g., C1-C5 alkyl, such as methyl or ethyl) or lower alkoxy (e.g., C1-C5 alkoxy, such as methoxy or ethoxy), and R ² is H, lower alkyl, or lower alkoxy. In an independent embodiment, R ¹ is Ci-C ₄ alkoxy or Ci-C ₄ alkyl, R ² is H or Ci-C ₄ alkyl, and R ⁴ is C5-C12 cycloalkyl. For example, R ¹ may be methoxy or methyl, R ² may be H, methyl, or ethyl, and R ⁴ is C5-C12 cycloalkyl. In an independent embodiment, R ¹ and R ² together with the carbon atoms to which they are attached form an aliphatic ring, and R ⁴ is cycloalkyl; for example, R ¹ and R ² together may be -(CH2-CH2)2-. In certain of the foregoing embodiments, R ⁵ -R ⁷ are H, or R ⁵ and R ⁶ are H and R ⁷ is lower alkyl, such as methyl, ethyl, or isobutyl.

In some embodiments, R ^x -R ³ independently are lower alkyl, and R ⁴ is C5-C12 alkyl or C5- C12 cycloalkyl. For example, R ^x -R ³ may independently be Ci-C ₄ alkyl, i.e., R ¹ , R ² , and R ³ independently may be selected from methyl, ethyl, propyl, isopropyl, or butyl (n-, sec-, iso-, or ie/ -butyl).

In any or all of the above embodiments, R ⁴ may be bridged alkyl. In any or all of the above embodiments, R ⁴ may be cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, or adamantyl. In one embodiment, R ¹ is methyl, R ² is ethyl, R ³ is 2-pyrrolyl, and R ⁴ is cycloheptyl, and the compound is N-((3'-ethyl-4'-methyl-[2,2'-bipyrrol]-5'-ylidene)methyl)cyc loheptanamine.

With respect to Formula II, R ⁸ and R ⁹ independently are hydrogen, alkyl, aryl, or arylalkyl; and R ¹⁰ and R ¹¹ independently are hydrogen, alkyl, or halo. In some embodiments, R ⁸ is alkyl, such as C1-C20 alkyl or C5-C15 alkyl; R ⁹ is hydrogen; R ¹⁰ is hydrogen or lower alkyl; and R ¹¹ is hydrogen, lower alkyl, or halo. In an independent embodiment, R ¹⁰ and R ¹¹ are lower alkyl, such as methyl or ethyl; R ⁸ is hydrogen or alkyl, such as C1-C20 alkyl or C5-C15 alkyl; and R ⁹ is alkyl, such as C1-C20 alkyl or C5-C15 alkyl, or arylalkyl. In another independent embodiment, R ⁸ and R ⁹ are independently arylalkyl, and R ¹⁰ and R ¹¹ are lower alkyl, such as methyl or ethyl. In some embodiments, the arylalkyl group is substituted, such as a

haloarylalkyl, e.g., 4-chlorobenzyl. In one embodiment, R ⁸ and R ⁹ are 4-chlorobenzyl, R ¹⁰ is methyl, and R ¹¹ is ethyl, and the compound is 5'-((3,5-bis(4-chlorobenzyl)-pyrrol-2- yl)methylene)-3'-ethyl-4'-methyl-2,2'-bipyrrole or a hydrochloride salt thereof.

Representative compounds include, but are not limited to:

The disclosed compounds can be combined with pharmaceutically acceptable carriers, excipients, and optionally sustained-release matrices, such as biodegradable polymers, to form therapeutic compositions. Therefore, also disclosed are pharmaceutical compositions including one or more of any of the compounds disclosed above, a pharmaceutically acceptable carrier and/or excipient. The composition may comprise a unit dosage form of the composition, and may further comprise instructions for administering the composition to a subject to treat or prevent malaria. The subject may have malaria or may be identified as being at risk of contracting malaria. Such pharmaceutical compositions may be used in methods for treating or preventing in a subject by administering to the subject a therapeutically effective amount of the composition.

The disclosed pharmaceutical compositions can be in the form of tablets, capsules, powders, granules, lozenges, liquid or gel preparations, such as oral, or sterile parenteral solutions or suspensions, and other forms known in the art.

Pharmaceutical compositions can be administered systemically or locally in any manner appropriate to the treatment of a given condition, including orally, parenterally, buccally, rectally, intranasally, transdermally, by inhalation spray, or via an implanted reservoir. The term "parenterally" as used herein includes, but is not limited to subcutaneous and intravascular administration, for example, by injection or infusion. Particular formulations of a disclosed pharmaceutical composition may depend, for example, on the mode of administration (e.g., oral or parenteral) and/or on the location of the infection to be treated (e.g., liver-stage and/or blood-stage malaria parasites).

Pharmaceutically acceptable carriers include, but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins (such as human serum albumin), buffers (such as phosphates), glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts or electrolytes such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol, sodium carboxymethylcellulose, polyacrylates, waxes, polyethylene-polyoxypropylene-block polymers, polyethylene glycol, and wool fat.

Tablets and capsules for oral administration can be in a form suitable for unit dose presentation and can contain conventional pharmaceutically acceptable excipients. Examples of these include binding agents such as syrup, acacia, gelatin, sorbitol, tragacanth, and

polyvinylpyrrolidone; fillers such as lactose, sugar, corn starch, calcium phosphate, sorbitol, or glycine; tableting lubricants, such as magnesium stearate, talc, polyethylene glycol, or silica; disintegrants, such as potato starch; and dispersing or wetting agents, such as sodium lauryl sulfate. Oral liquid preparations can be in the form of, for example, aqueous or oily

suspensions, solutions, emulsions, syrups or elixirs, or can be presented as a dry product for reconstitution with water or other suitable vehicle before use.

The pharmaceutical compositions can also be administered parenterally in a sterile aqueous or oleaginous medium. The composition can be dissolved or suspended in a non-toxic parenterally-acceptable diluent or solvent, e.g., as a solution in 1,3-butanediol. Commonly used vehicles and solvents include water, physiological saline, Hank's solution, Ringer's solution, and sterile, fixed oils, including synthetic mono- or di-glycerides, etc.

The compounds can be used in the form of pharmaceutically acceptable salts derived from inorganic or organic acids and bases, including, but not limited to: acetate, adipate, alginate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, citrate, camphorate, camphorsulfonate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, fumarate, glucoheptanoate, glycerophosphate, hemisulfate, heptanoate, hexanoate,

hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, oxalate, pamoate, pectinate, persulfate, 3- phenylpropionate, picrate, pivalate, propionate, succinate, tartrate, thiocyanate, tosylate, and undecanoate. Base salts include, but are not limited to, ammonium salts, alkali metal salts (such as sodium and potassium salts), alkaline earth metal salts (such as calcium and magnesium salts), salts with organic bases (such as dicyclohexylamine salts), N-methyl-D-glucamine, and salts with amino acids (such as arginine, lysine, etc.). Basic nitrogen-containing groups can be quaternized, for example, with such agents as Cl-8 alkyl halides (such as methyl, ethyl, propyl, and butyl chlorides, bromides, and iodides), dialkyl sulfates (such as dimethyl, diethyl, dibutyl, and diamyl sulfates), long-chain halides (such as decyl, lauryl, myristyl, and stearyl chlorides, bromides, and iodides), aralkyl halides (such as benzyl and phenethyl bromides), etc. Water or oil-soluble or dispersible products are produced thereby.

In some embodiments, the pharmaceutical composition further comprises a second therapeutic agent. Suitable second therapeutic agents include, but are not limited to, antimalarial agents. Exemplary antimalarial agents include quinine, quinidine, cinchoine, cinchonidine, 4- aminoquinolones such as amodiaquine, chloroquine, chloroquine analogues, quinoline analogues, hydroxychloroquine, pyrimethamine, chloroguanide (proguanil), atovaquone

(available as Malarone, a combination of atovaquone and proguanil), sulfonamides such as sulfadoxine and sulfamehtoxypyridazine, mefloquine, primaquine, artemisinin, artemisinin derivatives such as artesunate, artemether, arteether, and dihydroartemisinin, halofantrine (a phenanthrene methanol), Halfan, doxycycline, tetracycline, clindamycin, prodiginines, and combinations thereof. IV. Methods of Use

The compounds disclosed herein and pharmaceutically acceptable salts thereof

(hereinafter referred to interchangeably as the "compound" or the "compounds") may be used to inhibit a Plasmodium species. Some embodiments of the disclosed compounds are effective against chloroquine-resistant and/or multidrug-resistant Plasmodium species. Some

embodiments of the disclosed compounds are non-cytotoxic and/or non-genotoxic.

In one embodiment, a Plasmodium species is contacted with an effective amount of the compound. The Plasmodium species may be contacted in vitro, in vivo, or ex vivo. In any of the foregoing embodiments, contacting the Plasmodium species with an effective amount of the compound may comprise administering to a subject infected with the Plasmodium species a therapeutically effective amount of the compound or a therapeutically effective amount of a pharmaceutical composition comprising the compound. Administration may be performed by any suitable route, including but not limited to orally, parenterally (e.g., by subcutaneous, intramuscular, or intravascular injection), or rectally.

A method for treating or preventing malaria includes administering to a subject having malaria or at risk of developing malaria a therapeutically effective amount of (i) the compound, or (ii) a pharmaceutical composition comprising the compound and at least one

pharmaceutically acceptable carrier. Administration may be performed by any suitable route, including but not limited to orally, parenterally (e.g., by subcutaneous, intravascular, or intraperitoneal injection), or rectally.

The treatment can be used prophylactically in any subject in a demographic group at substantial risk for such diseases; for example, subjects who are traveling to areas where malaria is endemic (including, e.g., Southeast Asia, Africa, Papua New Guinea, Indonesia, Thailand, and India). Alternatively, subjects can be selected using more specific criteria, such as a probable or definitive diagnosis of malaria or Plasmodium sp. infection based on, for example, clinical signs and symptoms and/or laboratory evidence of parasite infection. An example of such a subject would be a person who presents clinically with symptoms resembling the flu (including periods of chills and fever lasting several hours and occurring every few days). In more severe cases, an infected subject may present with enlarged spleen and/or liver, anemia, and jaundice. Other subjects may be identified based on positive tests for parasite-specific proteins, including plasmodial histidine rich protein-2 (HRP-2) or parasite-specific lactate dehydrogenase (pLDH) or parasite DNA. A number of antibodies specific for Plasmodium parasites are available and are useful for diagnostic immunoassays or immunofluorescence techniques. Polymerase chain reaction (PCR) can also be used to diagnosis malaria in a subject (Am. J. Trop. Med. Hyg., 65(4):355-363, 2001).

In some embodiments, the subject is further administered a second therapeutic agent. The second therapeutic agent may be, for example, an antimalarial agent. Suitable antimalarial agents include, but are not limited to, quinine, quinidine, cinchoine, cinchonidine, 4- aminoquinolones such as amodiaquine, chloroquine, chloroquine analogues, quinoline analogues, hydroxychloroquine, pyrimethamine, chloroguanide (proguanil), atovaquone (available as Malarone, a combination of atovaquone and proguanil), sulfonamides such as sulfadoxine and sulfamehtoxypyridazine, mefloquine, primaquine, artemisinin, artemisinin derivatives such as artesunate, artemether, arteether, and dihydroartemisinin, halofantrine (a phenanthrene methanol), Halfan, doxycycline, tetracycline, clindamycin, prodiginines, and combinations thereof. The second therapeutic agent may be separately administered to the subject concurrently or sequentially in any order with the compound or pharmaceutically acceptable salt thereof. In some embodiments, the second therapeutic agent is combined in a pharmaceutical composition with the compound and at least one pharmaceutically acceptable carrier.

For prophylactic and therapeutic purposes, the compound can be administered to the subject by the oral route or in a single bolus delivery, via continuous delivery (for example, continuous transdermal, mucosal or intravenous delivery) over an extended time period, or in a repeated administration protocol (for example, by an hourly, daily or weekly, repeated administration protocol). The therapeutically effective dosage of the compound can be provided as repeated doses within a prophylaxis or treatment regimen that will yield clinically significant results to cure malaria or alleviate one or more symptoms or detectable conditions associated with malaria. Determination of effective dosages in this context is typically based on animal model studies followed up by human clinical trials and is guided by administration protocols that significantly suppress or eliminate parasitemia and/or reduce the occurrence or severity of malaria symptoms in the subject. Suitable models in this regard include, for example, murine, rat, non-human primate, and other accepted animal model subjects known in the art.

Alternatively, effective dosages can be determined using in vitro models. Using such models, only ordinary calculations and adjustments are required to determine an appropriate

concentration and dose to administer a therapeutically effective amount of the compound (for example, amounts that are effective to elicit a desired immune response or alleviate one or more symptoms of a targeted disease). The actual dosage of the compounds will vary according to factors such as the disease indication and particular status of the subject (for example, the subject's age, size, fitness, extent of symptoms, susceptibility factors, and the like), time and route of administration, other drugs or treatments being administered concurrently, as well as the specific pharmacology of the agent for eliciting the desired activity or biological response in the subject. Dosage regimens can be adjusted to provide an optimum prophylactic or therapeutic response. A therapeutically effective amount is also one in which any toxic or detrimental side effects of the compound is outweighed in clinical terms by therapeutically beneficial effects. Ideally, a therapeutically effective amount of a compound as disclosed herein is an amount sufficient to prevent, inhibit, reduce or relieve Plasmodium sp. infection and/or one or more symptoms of malaria without causing a substantial cytotoxic effect on host cells. A non-limiting range for a therapeutically effective amount of a compound within the methods and formulations of the disclosure is about 0.1 mg/kg body weight to about 200 mg/kg body weight in single or divided doses, such as about 5 mg/kg to about 100 mg/kg body weight, or about 25 mg/kg to about 80 mg/kg body weight. Dosage can be varied by the attending clinician to maintain a desired concentration, such as in systemic circulation. Higher or lower concentrations can be selected based on the mode of delivery, for example, trans-epidermal, rectal, oral, pulmonary, or intranasal delivery versus intravenous or subcutaneous delivery. Dosage can also be adjusted based on the release rate of the administered formulation, for example, of sustained release oral versus injected formulations, and so forth.

In some embodiments, a therapeutically effective amount of the compound, or a pharmaceutical composition comprising the compound, is administered in a single dose daily to the subject for a period of days, such as daily administration for 1-10 days, 1-7 days, or 1-4 days. In one exemplary dosing protocol, the subject is administered a single therapeutically effective dose daily for a period of four days. Alternatively, the therapeutically effective amount may be administered in divided doses over the course of a day. For example, the therapeutically effective amount may be divided into 2-4 smaller doses administered over the course of a day. In another exemplary dosing protocol, the subject is administered a single therapeutically effective dose.

In some embodiments, the subject is administered a sufficient amount of the compound, or a pharmaceutical composition comprising the compound, in one or more therapeutically effective amounts over one or more days to cure a malarial infection. A cure is defined as a

100% reduction of parasitemia, such as 100% reduction on day 5 after administration of one or more doses of the compound or pharmaceutical composition comprising the compound. In some embodiments, the subject remained free of parasitemia for at least 28 days after an initial dose of the compound or pharmaceutical composition comprising the compound. In certain embodiments, a single dose of the disclosed compound or pharmaceutical composition comprising the compound is curative.

V. Synthesis

Chemistry. The key precursors 6-43, which are involved in the synthesis of

prodiginines (PGs) and tambjamines (TAs) (Scheme 10), are depicted in FIGS. 2 and 3. By use of literature methodologies, MBC (6) and analogue 21 were prepared from readily available 4- methoxy-3-pyrrolin-2-one in two steps ²¹ and 2,2'-bipyrrole-5-carboxaldehydes 7, 8, and 10-18 were synthesized. ²⁰ The syntheses of various new pyrrole carboxaldehydes 9, 19, 20, and 22-39 are outlined in Schemes 1-9.

Synthesis of 4-(4-chlorophenyl)-[2,2'-bipyrrole]-5-carboxaldehyde (9). Synthesis of the aryl substituted 3-pyrrolin-2-one 48, a key synthone in the synthesis of bipyrrole- carboxaldehyde 9, began with the coupling of Boc-glycine (44) with 2,2-dimethyl-l,3-dioxane- 4,6-dione (Meldrum' s acid) to afford the acylated Meldrum acid, which was further converted into the desired intermediate 45 by an intramolecular cyclization and a subsequent

decarboxylation (Scheme l). ²² The compound 45 was treated with /?-toluenesulfonyl chloride in the presence of N,N-diisopropylethylamine (DIPEA) to give the tosylated product 46, in 89% yield, which was further subjected to Suzuki-coupling reaction with 4-chlorophenylboronic acid to give the N-Boc-4-aryl-3-pyrrolin-2-one 47. The desired 4-aryl-3-pyrrolin-2-one 48 was obtained in excellent yield by deprotection of the N-Boc group of 47 with trifluoroacetic acid. ²³ Using the reported Vilsmeier formylation method, ²¹ 48 was then smoothly transformed to 5- bromo-3-(4-chlorophenyl)-pyrrole-2-carboxaldehyde 49, which when further subjected to

Suzuki coupling with N-Boc-2-pyrroleboronic acid followed by deprotection of the N-Boc group gave the desired 2,2'-bipyrrole-5-carboxaldehyde 9, in 59% yield (Scheme l). ²⁰ B

Scheme 1. Synthesis of 4-(4-chlorophenyl)-[2,2'-bipyrrole]-5-carboxaldehyde (9) Synthesis of 2,2'-bipyrrole-5-carboxaldehyde (19). In 1988, Borger and Patel synthesized the 2,2'-bipyrrole-5-carboxaldehyde (19) in seven steps. ^8b Compund 19 was synthesized in two one-pot sequences from easily available pyrrole (50), as shown in Scheme 2. To that end, 50 was consecutively treated with N-chlorosuccinimide (NCS) and Vilsmeier reagent (POCb/DMF, in situ generation) under controlled temperatures to obtain the 5-chloro- pyrrole-2-carboxaldehyde (51) in good yield. ²⁴ The Suzuki cross-coupling of 51 with N-Boc-2- pyrroleboronic acid followed by deprotection of the N-Boc group provided the desired bipyrrolecarboxaldehyde 19 in 45% isolated yield (Scheme 2).

rt, 30 min, 45%

Scheme 2. Synthesis of 2,2'-bipyrrole-5-carboxaldehyde (19) Synthesis of 3-(pyrrol-2-yl)-4,5,6,7-tetrahydro-isoindole-l-carboxaldehyd e (20). The key intermediate 53 was prepared via BartoneZard's method, using 1-nitro-l-cyclohexene (52) as a starting material (Scheme 3). ²⁵ Upon treatment with NaOH in ethylene glycol under reflux, 53 was smoothly converted to 4,5,6,7-tetrahydro-isoindole (54) in 90% yield by successive hydrolysis and decarboxylation of the ester group. Using the standard Vilsmeier formylation method, 54 was then transformed to 4,5,6,7-tetrahydro-isoindole-l-carboxaldehyde (55), which when further treated with l,3-dibromo-5,5-dimethylhydantoin (DBDMH) ²⁰ in THF at -78 °C to room temperature provided the 3-bromo-4,5,6,7-tetrahydro-isoindole-l-carboxaldehyde (56). Subsequently, Suzuki cross-coupling reaction between 56 and N-Boc-2-pyrroleboronic acid and further deprotection of the N-Boc group led to the desired bipyrrole-carboxaldehyde 20 in good yield (Scheme 3).

I NaOH/H ₂ 0, 1 h, 75%

Scheme 3. Synthesis of 3-(pyrrol-2-yl)-4,5,6,7-tetrahydro-isoindole-l-carboxaldehyd e (20) Synthesis of isomeric [2,3'-bipyrrole]-5'-carboxaldehydes (22-25). To investigate the ring A positional effect on antimalarial activity, the isomeric bipyrrole-carboxaldehydes 22-25 were prepared, as shown in Scheme 4. Pyrrole-2-carboxaldehyde (40) and 3,5-dimethyl-pyrrole- 2-carboxaldehyde (42) were obtained from commercial sources, and the 3-methyl-pyrrole-2- carboxaldehyde (57) and 3-ethyl-pyrrole-2-carboxaldehyde (58) were prepared according to reported procedures. ²⁰ These pyrrole-2-carboxaldehydes were then converted into the corresponding 4-bromo-pyrrole-2-carboxaldehydes 59-62, via a regioselective bromination at 4- position using DBDMH in THF in good yields (Scheme 4). ²⁰ These 4-bromo-pyrrole-2- carboxaldehydes 59-62, were further subjected to Suzuki-coupling reaction with N-Boc-2- pyrroleboronic acid, and a subsequent treatment with LiOH in THF/MeOH (1 : 1) at 60 °C, resulted in the desired isomeric bipyrrole-caraboxaldehydes 22-25 (Scheme 4). i) Pd(PPh ₃ ) ₄ , dioxane/H ₂ 0

Na ₂ C0 ₃ , 100 °C, 4 h -A R2 N-Boc-2-pyrroleboronic acid

ii) LiOH, THF-MeOH, 60 °C, 2 h ' N

40: R-i = R ₂ = H 59: = R ₂ = H (75%) 22: R-i = R ₂ = H (70%)

42: R-i = R ₂ = Me 60: Ri = R ₂ = Me (78%) 23: R-, = R ₂ = Me (72%)

57: R-i = H, R ₂ = Me 61 : R, = H, R ₂ = Me (79%) ₂ 4: R-, = H, R ₂ = Me (67%)

58: R-i = H, R ₂ = Et 62: R, = H, R ₂ = Et (83%) ₂ 5: R, = H, R ₂ = Et (65%)

Scheme-4. Synthesis of isomeric [2,3'-bipyrrole]-5'-carboxaldehydes (22-25)

Synthesis of MBC's analogues (26-31) containing herteroaryl/aryl groups in the place of ring-A. To probe the exact role of the 2-pyrrolyl moiety (ring-A) on activity, various key carboxaldehyde precursors 26-31 were prepared in which the ring-A is completely replaced by various heterocycles and/or aryl moieties and the ring-B is substituted with short alkyl groups (Scheme 5). The 5-bromo-3,4-dimethyl-pyrrole-2-carboxaldehyde (65) was prepared in six steps according to the literature methods from acetaldehyde (63) and nitroethane (64), ²⁰ and it was subsequently subjected to Suzuki-coupling reaction with various boronic acids, and further deprotection of the Boc/TIPS group led to the corresponding carboxaldehydes 26-31

(Scheme 5).

i) Pd(PPh ₃ ) ₄ , dioxane/H ₂ 0

Scheme-5. Synthesis of MBC's analogues containing herteroaryl/aryl groups in the place of ring-A (26-31)

Synthesis of 3,4-dimethyl-[2,2'-bipyrrole]-5-carboxaldehydes where the ring-A contains C-alkyl groups (32-36). To investigate the effect of the ring-A alkyl substituents pattern on potency, various alkylated bipyrrole-carboxaldehyde precursors 32-36 were prepared as shown in Schemes 6 and 7. The 2-acetyl-pyrrole (66a), 2,4-dimethylpyrrole (67c), and 3- ethyl-2,4-dimethylpyrrole (67d) were obtained from commercial sources, and the 2-isobutyryl- pyrrole (66b) was prepared according to the literature methods. ²⁶ The compounds 66a and 66b were then converted into the corresponding 2-alkyl-pyrroles 67a and 67b, respectively, using LiAlH ₄ in THF under reflux (Scheme 6). By using standard procedures, the N-Boc-protected pyrroles 68a-68d were prepared in excellent yields from 67a-67d using di-tert-butyl dicarbonate (Boc ₂ 0) in the presence of 4-(dimethyl amino)pyridine (DMAP), and subsequently these were converted into the corresponding 5-alkyl-(l-tert-butoxycarbonylpyrrol-2-yl)boronic acids 69a-69d. ²⁸ The resultant boronic acids 69a-69d were carried forward into the Suzuki- coupling reaction with 65 without further purification to afford their corresponding [2,2'- bipyrrole]-5-carboxaldehydes 32-35 in good yields (Scheme 6).

66a: R- _| ^■ Me 67a: R _† = Et, R ₂ = R ₃ = 68a: R-| = Et, R ₂ = R ₃ =

66b: ^: ;-Pr 67b: R-i = i-Bu, R ₂ = R 68b: R-i = i-Bu, R ₂ = R

67c: Ri = R ₃ = Me, R 68c: R-, = R ₃ = Me, R _:

67d: Ri = R ₃ = Me, R 68d: Ri = R ₃ = Me, R n-BuLi/2,2,6,6-tetramethylpiperidine trimethyl borate, THF, -78 °C-rt, 24 h

65-85%

34: R-i = R ₃ = Me, R ₂ = H 69b: R-t = i-Bu, R ₂ = R

35: Ri = R ₃ = Me, R ₂ = Et 69c: Ri = R ₃ = Me, R _:

Scheme-6. Synthesis of 3,4-dimethyl-[2,2'-bipyrrole]-5-carboxaldehydes where the ring-A contains C-alkyl groups (32-35)

A simple and convenient method for the synthesis of N-Boc-4-ethyl-2-pyrrolboronic acid (71) via a regioselective boronylation of N-Boc-3-ethyl-pyrrole (70) was developed, ²⁰ using n- BuLi/2,2,6,6-tetramethylpiperidine, and trimethyl borate (Scheme 7, Experimental Section). Further investigations to expand the substrate scope of the regioselective boronylation as well as mechanistic studies are underway. Finally the 4'-ethyl-3,4-dimethyl-[2,2'-bipyrrole]-5- carboxaldehyde (36) was prepared in good yield via Suzuki coupling of 65 with boronic acid 71, followed by the deprotection of N-Boc group with LiOH (Scheme 7). The final compound 36 was fully characterized by extensive 2D NMR analysis.

Scheme 7. Synthesis of 4'-ethyl-3,4-dimethyl-[2,2'-bipyrrole]-5-carboxaldehyde (36)

Synthesis of 3-(imidazol-2-yl)-4,5,6,7-tetrahydro-isoindole-l-carboxaldeh yde (37).

To investigate the role of ring-A with an extra nitrogen atom on potency, the ring-A was replaced by an imidazole moiety, as in 37 (Scheme 8). The N-Boc-pyrrole 72 was prepared in 95% yield from compound 55 using B0C2O/DMAP, and subsequently the aldehyde group was protected by trimethyl orthoformate under acidic conditions to obtain the desired intermediate 73. The compound 73 was further reacted with triisopropyl borate/LDA in THF, and followed by aqueous solution of KHS0 ₄ /NH ₄ C1 at room temperature to provide the desired boronic acid 74 in excellent yield. ²⁰ Finally, the Suzuki cross-coupling reaction between 74 and 2-bromo- imidazole (75), and subsequent deprotection of the N-Boc group led to the desired

carboxaldehyde 37 in 65% isolated yield (Scheme 8).

i) LDA, triisopropyl borate

THF, 0 °C, 1 h

KHSO4/NH4CI

Scheme 8. Synthesis of 3-(imidazol-2-yl)-4,5,6,7-tetrahydro-isoindole-l-carboxaldeh yde (37) Synthesis of 3-methyl-4,5,6,7-tetrahydro-isoindole-l-carboxaldehyde (38) and 5,5'- methylenebis(4-ethyl-3-methyl-pyrrole-2-carboxaldehyde) (39). Two representative pyrrole aldehydes 38 and 39 (Scheme 9) were synthesized without ring-A. Initially, l-methyl-4,5,6,7- tetrahydro-isoindole (77) was synthesized from ethyl-4,5,6,7-tetrahydro-isoindole-l-carboxylate (53) via an unstable intermediate 76, using LiAlH ₄ in THF at 0 °C to room temperature in 85% isolated yield. The resultant alkyl-pyrrole 77 was further converted to 3-methyl-4, 5,6,7- tetrahydro-isoindole-l-carboxaldehyde (38) by Vilsmeier reagent (POCI3/DMF) (Scheme 9). Conversely, the bis(3-ethyl-4-methyl-pyrrol-2-yl)methane (79) was prepared from diethyl-5,5'- methylenebis(4-ethyl-3-methyl-2-pyrrolecarboxylate) (78) in excellent yields via a successive hydrolysis and a decarboxylation of the ester groups. Further Vilsmeier formylation of 79 provided the desired dicarboxaldehyde 39 in 73% isolated yield (Scheme 9).

Scheme 9. Synthesis of 3-methyl-4,5,6,7-tetrahydro-isoindole-l-carboxaldehyde (38) and 5,5'- methylenebis(4-ethyl-3-methyl-pyrrole-2-carboxaldehyde) (39) Synthesis of novel PGs (85-98) and TAs (99-187). The mono- and dialkyl pyrroles 80- 84 were synthesized (FIG. 4) using standardized procedures. ¹³ The acid-catalyzed condensation of either the alkyl pyrroles 80-84 or the commercially available alkyl/arylamines with various bipyrrole-carboxaldehydes and analogues 6-43, provided the desired PGs 85, 86, 88-98, and TAs 99-187, respectively, in good to excellent isolated yields (Scheme 10). The PG 85 was further treated with Mel/NaH in DMF to provide the N,N-dimethyl PG 87 in 85% isolated yield (Scheme 10 .

Scheme-10. Synthesis of novel PGs (85-98) and TAs (99-187) Synthesis of TA like Analogues (190, 191 and 194-196). Distinct syntheses were designed and executed to obtain a different class of TA like analogues 190, 191 and 194-196, in which the crucial ring-B of TAs is completely replaced by an alkylamide/amine linkage (Scheme 11). To that end, compound 188 was synthesized via a standard condensation method (EDCl/DMAP) from 44 and 1-adamantylamine in 85% yield. Removal of the Boc group of 188 by trifluoro acetic acid: water (1: 1) provided the intermediate 189 in good yield, ²⁹ which was further utilized in a condensation reaction with pyrrole-2-carboxylic acid to furnish the desired product 190. Treatment of 190 with LiAlH ₄ in THF at 0 °C to reflux conditions gave the 191 in 82% isolated yield (Scheme 11). Conversely, analogues 194-196, were also synthesized, as shown in Scheme 11. The pyrrole-2-carboxaldehyde (40) was subjected to Horner- Wadsworth- Emmons (HWE) reaction with methyl diethylphosphonoacetate in the presence of NaH to obtain the methyl-3-(pyrrol-2-yl)acrylate (192), ³⁰ which when hydrolyzed under basic (LiOH.H ₂ 0) conditions, furnished the 2-pyrrolyl acrylic acid 193. Condensation of 193 with 189 in the presence of EDCl/DMAP led to the corresponding condensed product 194, which was further treated with NaBH ₄ /NiCl2.6H ₂ 0 to give the saturated product 195. Treatment of 195 with LiAlH ₄ in THF at 0 °C to reflux conditions provided the desired product 196 in 78% yields (Scheme 11).

B

0 °C- reflux, 12 h, 78%

Scheme 11. Synthesis of novel analogues (190, 191 and 194-196) VI. EXAMPLES

General. NMR spectra were recorded on Bruker AMX-400, and AMX-600,

spectrometers at 400, 600 MHz (¾, and 100, 150 MHz ( ¹³ C). Experiments were recorded in CDCb, CD3OD, acetone-ifc and DMSO-ifc at 25 °C. Chemical shifts are given in parts per million (ppm) downfield from internal standard Me ₄ Si (TMS). HRMS (ESI) were recorded on a high-resolution (30000) thermo LTQ-Orbitrap Discovery hybrid mass spectrometer (San Jose, CA). Unless otherwise stated, all reagents and solvents were purchased from commercial suppliers and used without further purification. Reactions which required the use of anhydrous, inert atmosphere techniques were carried out under an atmosphere of argon/nitrogen.

Chromatography was executed on CombiFlash® Rf 200 instrument, using silica gel (230-400 mesh) and/or neutral alumina as the stationary phase and mixtures of ethyl acetate and hexane as eluents. Analytical HPLC analyses were performed on a Supelco Discovery HS C18 column (4.6 x 250 mm) with a linear elution gradient ranging from CH3OH/CH3CN/H2O

(40%/10%/50%) to CH3OH (100%) in 0.15% trifluoroacetic acid at a flow rate of 1 mL/min. A purity of > 95% has been established for all tested compounds.

Example 1

Compound Synthesis and Characterization

Synthesis of 4-Hydroxy-2-oxo-2,5-dihydro-pyrrole-l-carboxylic acid tert-butyl ester (45). To a stirred solution of N-(tert-butoxycarbonyl)-glycine (44; 5.0 g, 28.57 mmol) in 90 mL of anhydrous CH2CI2 (DCM) were added meldrum's acid (4.93 g, 34.28 mmol), and 4- dimethylaminopyridine (DMAP; 8.71 g, 71.42 mmol) under an argon atmosphere at 0 °C. A solution of isopropyl chloroformate (42.85 mL, 42.85 mmol, 1 N in toluene) was added dropwise, and the reaction mixture was stirred for 4 h at 0 °C. The reaction mixture was diluted with DCM (100 mL), washed with 15% KHS0 ₄ (2 x 70 mL), and organic layer was dried over Na ₂ S0 ₄ , and the solvent was evaporated under reduced pressure to give the acylated meldrum's acid. This material was then refluxed in ethyl acetate (600 mL) for 1 h and the solvent was evaporated under reduced pressure and the product was recrystallized from ethyl acetate to give the desired product 45 (3.46 g, 61%) as a white solid. ^l H NMR (DMSO-ifc, 400 MHz) δ 12.13 (br s, 1H), 4.88 (s, 1H), 4.14 (s, 2H), 1.44 (s, 9H); HRMS (ESI) calcd for C ₉ Hi ₃ NaN0 ₄ (M + Na) ⁺ 222.0737, found 222.0740.

Synthesis of 2-Oxo-4-(toluene-4-sulfonyloxy)-2,5-dihydropyrrole-l-carboxy lic acid tert-butyl ester (46). To a stirred solution of 45 (3.4 g, 17.08 mmol) in anhydrous CH2CI2 (150 mL) were added /?-toluenesulfonyl chloride (3.24 g, 17.08 mmol), and DIPEA (4.4 g, 34.17 mmol). The resulting reaction mixture was stirred for 6 h at 25 °C. Then the reaction mixture was washed with 5% HC1 (2 x 25 mL), brine and dried over anhydrous Na ₂ S0 ₄ . The organic solvent was removed under reduced pressure and the product was chromato graphed on silica gel, with ethyl acetate/hexanes as eluent, to afford the 46 (5.37 g, 89%) as a white solid. ^l H NMR (CDC1 ₃ , 400 MHz) δ 7.86 (d, = 8.4 Hz, 2H), 7.42 (d, = 8.4 Hz, 2H), 5.75 (s, 1H), 4.22 (d, / = 1.2 Hz, 2H), 2.50 (s, 3H), 1.52 (s, 9H); HRMS (ESI) calcd for Ci6Hi ₉ NaN0 ₆ S (M + Na) ⁺ 376.0825, found 376.0830.

Synthesis of 4-(4-Chloro-phenyl)-2-oxo-2,5-dihydro-pyrrole-l-carboxylic acid tert- butyl ester (47). To a degassed stirred solution of 46 (4.0 g, 11.33 mmol) and 4- chlorophenylboronic acid (2.65 g, 17.0 mmol) in 100 mL of THF at room temperature were added Pd(dppf)Cl2 (410 mg, 0.56 mmol) and a solution of cesium carbonate (11.05 g, 34.0 mmol) in water (15 mL). The reaction mixture was stirred at 25 °C for 1 h and then heated to reflux for 16 h. The reaction mixture was filtered through Celite and washed with ethyl acetate (400 mL). The organic layer was washed with saturated sodium bicarbonate (2 x 75 mL), and brine and dried over anhydrous Na ₂ S0 ₄ . Then the organic solution was concentrated under reduced pressure and the product was chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the pure product 47 (1.82 g, 55%) as a white solid. ^X H NMR (CDCb, 400 MHz) δ 7.50 (d, J = 8.7 Hz, 2H), 7.42 (d, J = 8.7 Hz, 2H), 6.42 (t, J = 1.5 Hz, 1H), 4.68 (d, / = 1.5 Hz, 2H), 1.61 (s, 9H); HRMS (ESI) calcd for CisHieNaClNOs (M + Na) ⁺ 316.0711, found 316.0713.

Synthesis of 4-(4-Chloro-phenyl)-l,5-dihydro-pyrrol-2-one (48). To a stirred solution of 47 (1.8 g, 6.14 mmol) in anhydrous CH2CI2 (25 mL) was added dropwise TFA (2.8 g, 24.57 mmol). The reaction mixture was stirred for an additional hour at 25 °C. The solvent was evaporated under reduced pressure and the crude material was then dissolved in ethyl acetate (200 mL). The organic layer was washed with 5% NaHC0 ₃ , and brine and dried over anhydrous Na ₂ S0 ₄ . The organic solvent was evaporated under reduced pressure and the solid material was washed with CH2CI2, to afford the pure product 48 (1.14 g, 94%) as a white solid. ^X H NMR (DMSO-ifc, 400 MHz) δ 8.15 (br s, 1H), 7.61 (d, = 8.6 Hz, 2H), 7.44 (d, = 8.6 Hz, 2H), 6.50 (t, = 1.5 Hz, 1H), 4.30 (s, 2H); HRMS (ESI) calcd for C10H9CINO (M + H) ⁺ 194.0367, found 194.0372.

Synthesis of 5-Bromo-3-(4-chloro-phenyl)-pyrrole-2-carboxaldehyde (49). To a stirred solution of diethylformamide (DEF; 1.57 g, 15.54 mmol) in anhydrous chloroform (10 mL) at 0 °C was added dropwise a solution of phosphorus oxybromide (POBr ₃ ; 3.62 g, 12.95 mmol) in chloroform (10 mL). The resulting thick suspension was stirred at 0 °C for 30 min to obtain the Vilsmeier complex as a solid. After the sample was dried in vacuo for 20 min, chloroform (50 mL) was added to the solid and the reaction mixture was cooled to 0 °C. The compound 48 (1.0 g, 5.18 mmol) was added portionwise, and the reaction mixture was warmed to room temperature and then heated at 70 °C for 16 h. The reaction mixture was poured onto ice-water (75 mL) and the pH of the aqueous solution was adjusted to pH 9-10 by treatment with 5 N NaOH. Dichloromethane (100 mL) was added to the resulting precipitate and the mixture was filtered through Celite. The two layers were separated and the aqueous layer was extracted with CH2CI2 (3 x 100 mL). The organic layers were combined, washed with brine and dried over anhydrous Na ₂ S0 ₄ . The solvent was removed under reduced pressure and the product was passed through a silica gel, with ethyl acetate/hexanes as eluent, to afford the pure 49 (806 mg, 55%) as a white solid. ^l H NMR (CDCh, 400 MHz) δ 10.05 (br s, 1H), 9.49 (s, 1H), 7.49-7.40 (m, 4H), 6.42 (d, J = 2.6 Hz, 1H); ¹³ C NMR (CDCh, 100 MHz) δ 178.2, 137.1, 134.5, 131.5, 130.9, 130.3, 129.9, 129.1, 128.9, 113.6, 113.1; HRMS (ESI) calcd for CnHgBrClNO (M + H) ⁺ 283.9472, found 283.9484.

Representative Procedure for the Synthesis of 4-(4-Chloro-phenyl)-[2,2']bipyrrolyl- 5-carboxaldehyde (9). To a degassed stirred solution of 49 (1.0 g, 3.53 mmol), and N-Boc-2- pyrroleboronic acid (1.11 g, 5.30 mmol) in 10% water/dioxane (50 mL) were added Pd(PPh ₃ ) ₄ (204 mg, 0.17 mmol) and Na ₂ C0 ₃ (749 mg, 7.06 mmol). The reaction mixture was stirred for 3 h at 100 °C and poured onto water (100 mL). The pH of the solution was lowered to pH 7 with 2 N HC1 and extracted with ethyl acetate (3 x 75 mL). The combined organic layers were washed with water and brine and dried over anhydrous Na ₂ S0 ₄ . The solvent was evaporated under reduced pressure and the residue was dissolved in methanol (25 mL) and evaporated the solvent to remove the volatile B(OMe) ₃ . This was then dissolved in THF (10 mL) and LiOH (850 mg, 35.33 mmol) in methanol (10 mL) was added dropwise under an argon atmosphere at room temperature. The resulting reaction mixture was stirred at room temperature for 30 min. On completion of the reaction, the solvent was removed under reduced pressure. The resulting solid was picked up with ethyl acetate (200 mL), washed with water and brine and dried over anhydrous Na ₂ S0 ₄ . The organic solvent was removed under reduced pressure and the product was chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the pure 9 (562 mg, 59%). ^l H NMR (DMSO-ifc, 400 MHz) δ 12.09 (br s, 1H), 11.31 (br s, 1H), 9.46 (s, 1H), 7.58 (d, = 8.7 Hz, 2H), 7.52 (d, = 8.7 Hz, 2H), 6.93 (m, 1H), 6.81 (m, 1H), 6.72 (d, = 2.5 Hz, 1H), 6.14 (m, 1H); ¹³ C NMR (DMSC fc, 100 MHz) δ 177.1, 135.6, 133.6, 132.6, 132.3, 130.5 (2C), 128.7 (2C), 127.5, 123.0, 120.2, 109.3, 108.1, 106.4; HRMS (ESI) calcd for

Ci ₅ Hi ₂ ClN ₂ 0 (M + H) ⁺ 271.0633, found 271.0639.

Synthesis of 5-Chloro-pyrrole-2-carboxaldehyde (51). To a stirred solution of pyrrole (50; 5.0 g, 74.62 mmol) in 200 mL of dry THF was added N-chlorosuccinimide (NCS; 9.92 g, 74.62 mmol) under an argon atmosphere at -78 °C. The reaction mixture was stirred for an additional 4 h at the same temperature and placed at -20 °C for overnight. To the reaction mixture was added dropwise Vilsmeier reagent (149.25 mmol, in-situ generation from

POCb/DMF, 0 °C, 1 h) in 100 mL of DCM at -20 °C. The reaction mixture was stirred for 10 h while it was allowed to warm to room temperature. The solvent was removed under reduced pressure and added 100 mL of water. To the stirred mixture, sodium hydroxide (2 N, 100 mL) was added slowly and the reaction mixture was allowed to stir for 1 h at room temperature. Ethyl acetate (300 mL) was added to the resulting precipitate, the two layers were separated and the aqueous layer was further extracted with ethyl acetate (2 x 100 mL). The organic layers were combined, washed with brine and dried over anhydrous Na ₂ S0 ₄ . The solvent was removed by rotary evaporation and the product was chromatographed on silica gel, with ethyl

acetate/hexanes as eluent, to afford the desired product 51 (3.46 g, 36%) as a white solid. ^l H NMR (CDCb, 400 MHz) δ 12.28 (br s, 1H), 9.31 (s, 1H), 6.85 (dd, J = 2.3, 4.0 Hz, 1H), 6.14 (dd, 7 = 2.3, 4.0 Hz, 1H); ¹³ C NMR (CDCb, 100 MHz) δ 178.2, 131.9, 126.0, 122.4, 110.0; HRMS (ESI) calcd for C5H5CINO (M + H) ⁺ 130.0054, found 130.0055.

Synthesis of [2,2'-Bipyrrole]-5-carboxaldehyde (19). Compound 19 (558 mg, 45%) was synthesized by the same procedure as described for 9. ^l H NMR (CDCI3, 400 MHz) δ 11.98 (br s, 1H), 11.24 (br s, 1H), 9.35 (s, 1H), 7.00 (dd, J = 2.3, 3.9 Hz, 1H), 6.89 (m, 1H), 6.73 (m, 1H), 6.54 (dd, = 2.3, 3.9 Hz, 1H), 6.12 (m, 1H); HRMS (ESI) calcd for C ₉ H ₉ N ₂ 0 (M + H) ⁺ 161.0709, found 161.0713.

Synthesis of Ethyl 4,5,6,7-tetrahydro-isoindole-l-carboxylate (53). To a stirred solution of 52 (5.0 g, 39.37 mmol) and ethyl isocyanoacetate (5.33 g, 47.24 mmol) in 1 : 1 mixture of THF and ethanol (100 mL) was added portion- wise anhydrous potassium carbonate (10.86 g, 78.74 mmol). The reaction mixture was then stirred at room temperature for 3 days. The mixture was poured into water (100 mL), acidified to pH 5 with 2 N HC1, and extracted with diethyl ether (3 x 100 mL). The combined organic layers were washed with brine and dried over anhydrous Na ₂ S0 ₄ . The solvent was evaporated under reduced pressure and the product was chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the pure product 53 (4.93 g, 65%) as a white solid. ^l H NMR (CDCb, 400 MHz) δ 9.28 (br s, 1H), 6.67 (d, = 2.9 Hz, 1H), 4.33 (q, = 7.1 Hz, 2H), 2.85 (t, 7 = 5.8 Hz, 2H), 2.57 (t, = 6.0 Hz, 2H), 1.77 (m, 4H), 1.38 (t, J = 7.1 Hz, 3H); HRMS (ESI) calcd for CnHi ₆ N0 ₂ (M + H) ⁺ 194.1176, found 194.1184.

Synthesis of 4,5,6,7-Tetrahydro-isoindole (54). Sodium hydroxide (1.47 g, 36.71 mmol) was added to a solution of 53 (3.8 g, 18.35 mmol) in anhydrous ethylene glycol (20 mL) under an argon atmosphere at room temperature, and the reaction mixture was heated to reflux and stirred at refluxing temperature for an hour. After cooling to room temperature, the reaction mixture was taken up in n-hexane, washed with water and dried over anhydrous Na ₂ S0 ₄ .

Evaporation of the solvent under reduced pressure afforded the 54 (2.0 g, 90%) as a white solid that was directly used in the next step without further purification. ^l H NMR (CDCb, 400 MHz) δ 7.92 (br s, 1H), 6.53 (d, J = 2.6 Hz, 2H), 2.67 (m, 4H), 1.80 (m, 4H); HRMS (ESI) calcd for CsHiiN (M + H) ⁺ 122.0964, found 122.0969.

Representative Procedure for the Synthesis of 4,5,6,7-Tetrahydro-isoindole-l- carboxaldehyde (55) by Standard Vilsmeier Conditions. Phosphorus oxychloride (POCb; 5.05 g, 33.05 mmol) was added dropwise to dimethylformamide (DMF; 2.41 g, 33.05 mmol) at 0 °C. The resulting solution was stirred at 0 °C until the formation of the Vilsmeier complex as a solid. After the solid was dried in vacuo for 20 min, dichloromethane (50 mL) was added to the solid and the reaction mixture was cooled to 0 °C. A solution of 54 (2.0 g, 16.52 mmol) in DCM (50 mL) was added dropwise, and the reaction mixture was warmed to room temperature and then stirred for 10 h. After removing all solvent under vacuo, the residue was mixed with water (100 mL). To the stirred mixture, sodium hydroxide (5.28 g, 132.23 mmol) was added slowly and the reaction mixture was allowed to stir for 1 h at room temperature. Ethyl acetate (200 mL) was added to the resulting precipitate, the two layers were separated, and the aqueous layer was further extracted with ethyl acetate (2 x 50 mL). The organic layers were combined, washed with brine and dried over anhydrous Na ₂ S0 ₄ . The solvent was removed by rotary evaporation and the product was chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the desired product 55 (1.84 g, 75%) as a white solid. ^l H NMR (CDCI3, 400 MHz) δ 10.23 (br s, 1H), 9.51 (s, 1H), 6.87 (d, = 2.8 Hz, 1H), 2.86 (t, J = 5.9 Hz, 2H), 2.55 (t, = 6.0 Hz, 2H), 1.80 (m, 4H); HRMS (ESI) calcd for C ₉ Hi ₂ NO (M + H) ⁺ 150.0913, found 150.0920.

Representative Procedure for the Synthesis of 3-Bromo-4,5,6,7-tetrahydro- isoindole-l-carboxaldehyde (56). To a stirred solution of 55 (2.0 g, 13.42 mmol) in THF (100 mL) was added portion- wise DBDMH (1.90 g, 6.71 mmol) in a period of 10 min at -78 °C. Then the reaction mixture was stirred for 5 h while it was allowed to warm to room temperature. The reaction was quenched with 5% aqueous KHS0 ₄ solution, and extracted with ethyl acetate (3 x 75 mL). The combined organic layers were washed with brine and dried over anhydrous Na ₂ S0 ₄ . The solvent was evaporated under reduced pressure and the product was

chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the pure product 56 (2.48 g, 82%). ^l H NMR (CDCI3, 400 MHz) δ 10.60 (br s, 1H), 9.41 (s, 1H), 2.83 (m, 2H), 2.42 (m, 2H), 1.77 (m, 4H); ¹³ C NMR (CDCI3, 100 MHz) δ 175.7, 134.7, 128.9, 122.7, 110.5, 22.8, 22.6, 21.3, 21.0; HRMS (ESI) calcd for C ₉ HnBrNO (M + H) ⁺ 228.0019, found 228.0031.

Synthesis of 3-(Pyrrol-2-yl)-4,5,6,7-tetrahydro-isoindole-l-carboxaldehyd e (20).

Compound 20 (682 mg, 72%) was synthesized by the same procedure as described for 9. ^l H

NMR (DMSO-ifc + CDCI3, 400 MHz) δ 10.64 (br s, 1H), 10.35 (br s, 1H), 8.77 (s, 1H), 6.21 (s, 1H), 5.81 (s, 1H), 5.56 (s, 1H), 2.19 (s, 2H), 1.98 (s, 2H), 1.16 (m, 4H); ¹³ C NMR (DMSO-d ₆ + CDCb, 100 MHz) δ 173.0, 133.1, 128.8, 125.6, 122.5, 117.9, 116.7, 108.2, 107.5, 21.9, 21.5, 21.1, 19.6; HRMS (ESI) calcd for C13H15N2O (M + H) ⁺ 215.1179, found 215.1188.

Synthesis of Compounds 59-62. Compounds 59 (1.36 g, 75%), 60 (1.27 g, 78%), 61 (1.35 g, 79%), and 62 (1.35 g, 83%) were synthesized by the same procedure as described for 56.

4-Bromo-pyrrole-2-carboxaldehyde (59). 1H NMR (CDCb, 400 MHz) δ 10.16 (br s, 1H), 9.49 (d, = 1.0 Hz, 1H), 7.15 (m, 1H), 7.00 (m, 1H); HRMS (ESI) calcd for C ₅ H ₅ BrNO (M + H) ⁺ 173.9549, found 173.9555.

4-Bromo-3,5-dimethyl-pyrrole-2-carboxaldehyde (60). ^l U NMR (CDCb, 400 MHz) δ

10.82 (br s, 1H), 9.45 (s, 1H), 2.36 (s, 3H), 2.28 (s, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 176.2, 137.0, 133.0, 127.7, 101.5, 12.2, 10.0; HRMS (ESI) calcd for C ₇ H ₉ BrNO (M + H) ⁺ 201.9862, found 201.9871.

4-Bromo-3-methyl-pyrrole-2-carboxaldehyde (61). ^l H NMR (acetone-<i<5, 400 MHz) δ 11.17 (br s, 1H), 9.69 (d, = 0.7 Hz, 1H), 7.25 (d, = 3.2 Hz, 1H), 2.32 (s, 3H); HRMS (ESI) calcd for C ₆ H ₇ BrNO (M + H) ⁺ 187.9705, found 187.9711.

4-Bromo-3-ethyl-pyrrole-2-carboxaldehyde (62). ^X H NMR (CDCb, 400 MHz) δ 10.08 (br s, 1H), 9.34 (s, 1H), 7.20 (d, = 2.6 Hz, 1H), 2.47 (q, = 7.6 Hz, 2H), 1.25 (t, = 7.6 Hz, 3H); HRMS (ESI) calcd for C ₇ H ₉ BrNO (M + H) ⁺ 201.9862, found 201.9869.

Synthesis of 22-25. Compounds 22 (647 mg, 70%), 23 (673 mg, 72%), 24 (623 mg,

67%), and 25 (608 mg, 65%) were synthesized by the same procedure as described for 9, with modifying the reaction conditions for deprotection of N-Boc group. The crude material was dissolved in THF (10 mL) and LiOH (10 equiv.) in methanol (10 mL) was added dropwise under an argon atmosphere. The resulting mixture was stirred at 60 °C for 2 h.

[2,3 '-Bipyrrole]-5'-carboxaldehyde (22). ^l H NMR (CD3OD, 400 MHz) δ 9.43 (d, = 1.0

Hz, 1H), 7.37 (dd, / = 1.6, 2.5 Hz, 1H), 7.15 (d, = 1.6 Hz, 1H), 6.70 (dd, / = 1.5, 2.7 Hz, 1H), 6.23 (dd, = 1.5, 3.4 Hz, 1H), 6.10 (dd, = 2.7, 3.4 Hz, 1H); ¹³ C NMR (CD3OD, 100 MHz) δ 180.7, 134.4, 127.7, 123.8, 122.6, 118.1, 117.2, 109.4, 104.7; HRMS (ESI) calcd for C9H9N2O (M + H) ⁺ 161.0709, found 161.0713. Note. Two NH protons are not appering under these conditions.

2 ',4'-Dimethyl-[2,3 '-bipyrrole]-5'-carboxaldehyde (23). ^X H NMR (DMSO-ifc, 400 MHz) δ 11.68 (br s, 1H), 10.59 (br s, 1H), 9.51 (s, 1H), 6,76 (br s, 1H), 6.08 (br s, 1H), 5.94 (br s, 1H),

2.28 (s, 3H), 2.24 (s, 3H); ¹³ C NMR (DMSO-ifc, 100 MHz) δ 176.4, 135.2, 129.8, 127.7, 124.2, 117.3, 117.1, 107.9, 107.0, 12.1, 9.5; HRMS (ESI) calcd for C11H13N2O (M + H) ⁺ 189.1022, found 189.1026.

4'-Methyl-[2,3'-bipyrrole]-5'-carboxaldehyde (24). ^l H NMR (DMSO-ifc, 600 MHz) δ 11.78 (br s, 1H), 10.78 (br s, 1H), 9.64 (s, 1H), 7.33 (d, = 3.0 Hz, 1H), 6.71 (dd, / = 1.8, 2.4 Hz, 1H), 6.10 (dd, = 1.8, 3.0 Hz, 1H), 6.07 (dd, / = 2.4, 3.0 Hz, 1H), 2.41 (s, 3H); ¹³ C NMR (DMSC fc+ CDCh, 100 MHz) δ 176.2, 128.7, 125.8, 124.5, 122.1, 118.1, 115.6, 107.1, 104.0, 8.9; HRMS (ESI) calcd for C10H11N2O (M + H) ⁺ 175.0866, found 175.0871.

4'-Ethyl-[2,3'-bipyrrole]-5'-carboxaldehyde (25). ^l H NMR (DMSO-ifc, 600 MHz) δ 9.69 (s, 1H), 7.40 (d, = 2.7 Hz, 1H), 6.70 (dd, = 1.7, 2.7 Hz, 1H), 6.25 (d, = 3.2 Hz, 1H), 6.16 (dd, = 2.7, 3.2 Hz, 1H), 2.70 (q, = 7.3 Hz, 2H), 1.12 (t, / = 7.3 Hz, 3H); HRMS (ESI) calcd for C11H13N2O (M + H) ⁺ 189.1022, found 189.1027. Note. Two NH protons are not appering under these conditions.

Synthesis of 26-31. Compounds 26 (276 mg, 55%), 27 (266 mg, 57%), 28 (296 mg, 63%), 29 (346 mg, 68%), 30 (346 mg, 67%), and 31 (385 mg, 65%) were synthesized by the same procedure as described for 9 with modifying the reaction conditions for the deprotection of N- triisopropylsilyl group. The crude material was dissolved in THF (10 mL) and TBAF (2 equiv.) was added dropwise under an argon atmosphere. The resulting mixture was stirred at room temperature for 15 min.

r,3,4-Trimethyl-[2,2 '-bipyrrole]-5-carboxaldehyde (26). ^X H NMR (CDCI3, 400 MHz) δ 9.62 (s, 1H), 8.84 (br s, 1H), 6.77 (dd, = 1.8, 2.4 Hz, 1H), 6.28 (dd, = 1.8, 3.7 Hz, 1H), 6.23 (dd, = 2.4, 3.7 Hz, 1H), 3.61 (s, 3H), 2.33 (s, 3H), 2.02 (s, 3H); ¹³ C NMR (CDCI3, 100 MHz) δ 176.8, 131.8, 129.6, 129.0, 124.3, 124.2, 120.4, 111.3, 108.4, 34.8, 9.6, 9.0; HRMS (ESI) calcd for Ci2Hi ₄ NaN ₂ 0 (M + Na) ⁺ 225.0998, found 225.1006.

3,4-Dimethyl-[2,3'-bipyrrole]-5-carboxaldehyde (27). ^X H NMR (CDCI3, 400 MHz) δ 9.52 (s, 1H), 9.10 (br s, 1H), 8.64 (br s, 1H), 7.12 (m, 1H), 6.89 (m, 1H), 6.48 (m, 1H), 2.31 (s, 3H), 2.15 (s, 3H); ¹³ C NMR (CDCI3, 100 MHz) δ 175.4, 134.3, 133.3, 127.9, 119.1, 117.1, 116.6, 115.5, 106.9, 9.8, 8.9; HRMS (ESI) calcd for CnHi2NaN ₂ 0 (M + Na) ⁺ 189.1022, found 189.1028.

5-(Furan-2-yl)-3,4-dimethyl-pyrrole-2-carboxaldehyde (28). ^X H NMR (CDCI3, 400 MHz) δ 9.63 (s, 1H), 9.52 (br s, 1H), 7.48 (dd, = 1.6, 2.8 Hz, 1H), 6.64 (dd, = 1.6, 3.6 Hz,

1H), 6.52 (dd, = 2.8, 3.6 Hz, 1H), 2.30 (s, 3H), 2.17 (s, 3H); ¹³ C NMR (CDCI3, 100 MHz) δ

176.8, 146.5, 142.1, 132.1, 128.6, 128.0, 117.9, 111.9, 107.8, 9.6, 8.6; HRMS (ESI) calcd for

CnHiiNaN ₂ 0 (M + Na) ⁺ 212.0682, found 212.0689. 3,4-Dimethyl-5-(thiophen-2-yl)-pyrrole-2-carboxaldehyde (29). ^l U NMR (CDCb, 400 MHz) δ 9.63 (s, 1H), 9.53 (br s, 1H), 7.37 (dd, J = 1.6, 2.7 Hz, 1H), 7.34 (dd, J = 1.6, 3.5 Hz, 1H), 7.13 (dd, 7 = 2.7, 3.5 Hz, 1H), 2.33 (s, 3H), 2.21 (s, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 176.8, 133.6, 132.6, 131.4, 128.9, 127.8, 125.7, 124.2, 118.9, 9.9, 8.9; HRMS (ESI) calcd for CiiHiiNaNOS (M + Na) ⁺ 228.0454, found 228.0459.

3,4-Dimethyl-5-phenyl-pyrrole-2-carboxaldehyde (30). ^l U NMR (CDCb, 400 MHz) δ 9.64 (s, 1H), 9.49 (br s, 1H), 7.52 (m, 2H), 7.46 (m, 2H), 7.39 (m, 1H), 2.34 (s, 3H), 2.17 (s, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 176.9, 137.0, 132.6, 131.7, 129,0, 128.9 (2C), 128.2, 127.8 (2C), 118.6, 9.8, 9.0; HRMS (ESI) calcd for Ci ₃ Hi ₃ NaNO (M + Na) ⁺ 222.0889, found 222.0897.

5-(Indol-2-yl)-3,4-dimethyl-pyrrole-2-carboxaldehyde (31 ). ^X H NMR (DMSO-ifc, 400

MHz) δ 11.43 (br s, 2H), 9.62 (s, 1H), 7.44 (m, 2H), 7.09 (m, 2H), 6.82 (s, 1H), 2.29 (s, 3H), 2.21 (s, 3H); ¹³ C NMR (CDCb + DMSC fc, 100 MHz) δ 177.1, 136.1, 130.9, 129.6, 129.2, 128.8, 128.3, 122.1, 120.2, 119.6, 118.4, 111.2, 101.5, 10.0, 8.5; HRMS (ESI) calcd for

C15H15N2O (M + H) ⁺ 239.1179, found 239.1188.

Representative Procedure for the Synthesis of 2- Ethyl-pyrrole (67a). To a stirred suspension of LiAlH ₄ (3.49 g, 91.74 mmol) in dry THF (50 niL) was added dropwise 66a (5.0 g, 45.87 mmol) in THF (50 mL) at 0 °C. Then the resulting solution was heated to reflux overnight. The reaction was quenched with saturated solution of sodium sulfate. The insoluble solid was filtrated off, and washed with DCM (100 mL). Then the combined organic solution was concentrated under reduced pressure and the product was chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the desired product 67a (4.0 g, 92%).

2-Isobutyl-pyrrole (67b). (4.26 g, 95%); HRMS (ESI) calcd for C ₈ Hi ₄ N (M + H) ⁺ 124.1121, found 124.1126.

Representative Procedure for the Synthesis of tert-Butyl 2-ethyl-pyrrole- 1-carboxylate (68a). 4-(Dimethyl-amino)pyridine (DMAP; 257 mg, 2.10 mmol) was added to a stirred solution of 67a (2.0 g, 21.05 mmol), and di-tert-butyl dicarbonate (Βο¾0; 6.23 g, 27.36 mmol) in acetonitrile (50 mL) and the reaction left to stir for 1 h at room temperature. Dichloromethane (150 mL) was added and the solution was washed with water and brine and dried over anhydrous Na ₂ S0 ₄ . The solvent was removed by rotary evaporation and the product was chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the pure 68a (3.90 g, 95%). HRMS (ESI) calcd for CnHi ₈ N0 ₂ (M + H) ⁺ 196.1332, found 196.1335.

tert-Butyl 2-isobutyl-pyrrole-l-carboxylate (68b). (3.40 g, 94%), ^l U NMR (CDCb, 400

MHz) δ 7.21 (dd, J = 1.6, 2.4 Hz, 1H), 6.09 (dd, = 1.6, 3.6 Hz, 1H), 5.95 (dd, 7 = 2.4, 3.6 Hz, 1H), 2.73 (d, J = 7.0 Hz, 2H), 1.93 (m, 1H), 1.61 (s, 9H), 0.94 (d, J = 6.3 Hz, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 149.6, 135.1, 120.9, 112.3, 109.7, 83.1, 37.8, 28.0 (3C), 27.7, 22.5 (2C): HRMS (ESI) calcd for C13H22NO2 (M + H) ⁺ 224.1645, found 224.1649.

tert-Butyl 2,4-dimethyl-pyrrole-l-carboxylate (68c). (3.77 g, 92%), ^X H NMR (CDCb, 400 MHz) δ 6.94 (s, 1H), 5.80 (s, 1H), 2.41 (s, 3H), 2.02 (s, 3H), 1.60 (s, 9H); ¹³ C NMR

(CDCb, 100 MHz) δ 149.6, 131.6, 120.4, 117.5, 114.2, 82.8, 28.1 (3C), 15.4, 11.7; HRMS (ESI) calcd for CiiHisNOi (M + H) ⁺ 196.1332, found 196.1339.

tert-Butyl 3-ethyl-2,4-dimethyl-pyrrole-l-carboxylate (68d). (3.26 g, 90%), ^X H NMR (CDCb, 400 MHz) δ 6.96 (s, 1H), 2.38 (q, = 7.6 Hz, 2H), 2.37 (s, 3H), 2.01 (s, 3H), 1.61 (s, 9H), 1.07 (t, = 7.6 Hz, 3H); HRMS (ESI) calcd for C13H22NO2 (M + H) ⁺ 224.1645, found 224.1653.

Representative Procedure for the Synthesis of (l-(tert-Butoxycarbonyl)-5-ethyl-pyrrol- 2-yl)horonic acid (69a). To a stirred solution of 2,2,6,6-tetramethylpiperidine (2.60 g, 18.46 mmol) in dry THF (50 mL) was added dropwise n-BuLi (1.6 M in pentane, 12.5 mL, 20.0 mmol) under an argon atmosphere at -78 °C. The reaction mixture was allowed to warm to 0 °C and maintained at that temperature for 30 min. After cooling again to -78 °C, a solution of 68a (3.0 g, 15.38 mmol) in THF (10 mL) was added. The reaction mixture was stirred for 2 h at -78 °C prior to the addition of trimethyl borate (7.92 g, 76.92 mmol). The solution was allowed to react at ambient temperature overnight. The reaction mixture was diluted with EtOAc (200 mL), washed with water, and brine solution and dried over anhydrous Na2S0 ₄ . The solvent was removed by rotary evaporation to furnish the desired product 69a (3.12 g, 85%) as a brown solid. The product 69a was carried forward into the next reaction without further purification. The products 69b (1.82 g, 76%), 69c (1.59 g, 65%), and 69d (1.62 g, 68%) were also carried forward into the next reaction without further purification.

Synthesis of 32-35. Compounds 32 (403 mg, 75%), 33 (467 mg, 77%), 34 (1.59 g,

57%), and 35 (1.62 g, 55%) were synthesized by the same procedure as described for 9.

5'-Ethyl-3,4-dimethyl-[2,2 '-bipyrrole]-5-carboxaldehyde (32). ^l U NMR (DMSO-ifc, 600 MHz) δ 10.99 (s, 1H), 10.94 (br s, 1H), 9.46 (s, 1H), 6.35 (br s, 1H), 5.89 (br s, 1H), 2.61 (br s, 2H), 2.22 (s, 3H), 2.06 (s, 3H), 1.21 (br s, 3H); ¹³ C NMR (CDCb + DMSO-ifc, 150 MHz) δ 175.0, 135.6, 131.8, 130.9, 127.5, 122.0, 115.3, 108.9, 106.0, 20.3, 13.6, 9.9, 8.9; HRMS (ESI) calcd for C13H17N2O (M + H) ⁺ 217.1335, found 217.1348.

5'-Isobutyl-3,4-dimethyl-[2,2 '-bipyrrole]-5-carboxaldehyde (33). ^l H NMR (CDCb +

DMSO-ifc, 400 MHz) δ 11.18 (br s, 1H), 10.92 (br s, 1H), 9.24 (s, 1H), 6.40 (br s, 1H), 5.85 (s, 1H), 2.41 (d, J = 7.1 Hz, 2H), 2.17 (s, 3H), 2.04 (s, 3H), 1.86 (m, 1H), 0.85 (d, J = 6.4 Hz, 6H); ¹³ C NMR (CDCb + DMSO-ifc, 150 MHz) δ 173.6, 134.4, 134.2, 133.3, 127.5, 122.3, 116.8, 110.2, 107.9, 37.3, 29.1, 22.4 (2C), 10.3, 8.7; HRMS (ESI) calcd for C15H21N2O (M + H) ⁺ 245.1648, found 245.1660.

3,3 ',4,5'-Tetramethyl-[2,2 '-bipyrrole]-5-carbaldehyde (34). 1H NMR (CDCb, 400 MHz) δ 9.52 (s, 1H), 9.24 (br s, 1H), 8.40 (br s, 1H), 5.84 (d, = 2.6 Hz, 1H), 2.31 (s, 6H), 2.16 (s, 3H), 2.09 (s, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 174.2, 130.4, 127.4, 127.2, 117.0, 116.7, 116.6, 107.7 (2C), 11.6, 11.1, 8.6, 7.8; HRMS (ESI) calcd for C13H17N2O (M + H) ⁺ 217.1335, found 217.1348.

4'-Ethyl-3,3 ',4,5'-tetramethyl-[2,2 '-bipyrrole]-5-carboxaldehyde (35). HRMS (ESI) calcd for C15H21N2O (M + H) ⁺ 245.1648, found 245.1656.

Synthesis of (l-(tert-Butoxycarbonyl)-4-ethyl-pyrrol-2-yl)boronic acid (71).

Compound 71 (1.81 g, 74%) was synthesized by the same procedure as described for 69a. The product 71 was carried forward into the next reaction without further purification.

Synthesis of 4'-Ethyl-3,4-dimethyl-[2,2'-bipyrrole]-5-carboxaldehyde (36).

Compound 36 (413 mg, 77%) was synthesized by the same procedure as described for 9. ^l H NMR (DMSO-ifc, 400 MHz) δ 11.26 (br s, 1H), 10.75 (br s, 1H), 9.48 (s, 1H), 6.70 (s, 1H), 6.35 (s, 1H), 2.45 (q, = 7.5 Hz, 2H), 2.22 (s, 3H), 2.07 (s, 3H), 1.15 (t, = 7.5 Hz, 3H); ¹³ C NMR (DMSO-ifc, 100 MHz) δ 173.4, 130.8, 129.8, 126.3, 125.6, 122.2, 122.0, 1 14.6, 107.4, 18.6, 14.0, 8.9, 7.3; HRMS (ESI) calcd for C13H17N2O (M + H) ⁺ 217.1335, found 217.1346.

Synthesis of tert-Butyl l-formyl-4,5,6,7-tetrahydro-isoindole-2-carboxylate (72). Compound 72 (3.17 g, 95%) was synthesized by the same procedure as described for 68a. ^l H NMR (CDCb, 400 MHz) δ 10.38 (s, 1H), 7.14 (s, 1H), 2.88 (t, = 5.8 Hz, 2H), 2.52 (t, = 5.6 Hz, 2H), 1.74 (m, 4H), 1.69 (s, 9H); ¹³ C NMR (CDCb, 100 MHz) δ 183.4, 148.7, 137.3, 129.1, 123.8, 122.7, 84.8, 28.0 (3C), 24.2, 22.7, 22.6, 21.5; HRMS (ESI) calcd for Ci ₄ Hi ₉ NaN0 ₃ (M + Na) ⁺ 272.1257, found 272.1263.

Synthesis of tert-Butyl l-(dimethoxymethyl)-4,5,6,7-tetrahydro-isoindole-2- carboxylate (73). A solution of aldehyde 72 (2.0 g, 8.03 mmol), trimethyl orthoformate (1.70 g, 16.06 mmol) and a catalytic amount (30 mg) of /?-toluenesulfonic acid (PTSA) in MeOH (20 mL) was stirred at room temperature for 1 h. The reaction mixture was diluted with Et20 (200 mL) and washed with a solution of NaHC0 ₃ . The organic layer was washed with water and dried over anhydrous Na2S0 ₄ . The solvent was removed by rotary evaporation and the product was chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the pure product 73 (2.01 g, 85%). HRMS (ESI) calcd for Ci ₆ H ₂₆ N0 ₄ (M + H) ⁺ 296.1856, found

296.1863.

Synthesis of (3-Formyl-4,5,6,7-tetrahydro-isoindol-l-yl)boronic acid (74). To a stirred solution of 73 (1.2 g, 4.06 mmol) in THF (10 mL) was added triisopropyl borate (1.14 g, 6.10 mmol). The solution was cooled to 0-5 °C in an ice bath, and lithium diisopropylamide (LDA; 2 N, 4 mL, 8.13 mmol) was added over 20 min and stirring was continued for an additional hour. The saturated ammonium chloride (5 mL) and 10% aqueous potassium bisulfate solution (50 mL) were added to adjust the pH 2, followed by stirring at room temperature for 2 h. The reaction mixture was diluted with EtOAc (200 mL), washed with brine solution and dried over anhydrous Na ₂ S0 ₄ . The solvent was removed by rotary evaporation to furnish the desired product 74 (738 mg, 94%) as an orange solid. The product 74 was carried forward into the next reaction without further purification.

Synthesis of 3-(Imidazol-2-yl)-4,5,6, 7-tetrahydro-isoindole-l-carboxaldehyde (37). Compound 37 (478 mg, 65%) was synthesized by the same procedure as described for 9. ^l H

NMR (DMSO-ifc, 400 MHz) δ 12.02 (s, 1H), 11.68 (br s, 1H), 9.53 (s, 1H), 7.26 (br s, 1H), 7.07 (br s, 1H), 2.79 (m, 4H), 1.72 (m, 4H); ¹³ C NMR (CDC1 ₃ + DMSO-ifc, 100 MHz) δ 176.9, 139.6, 132.5, 129.3, 127.3, 126.2, 120.7, 117.2, 22.8, 22.6, 22.3, 20.9; HRMS (ESI) calcd for

Ci ₂ Hi ₄ N ₃ 0 (M + H) ⁺ 216.1131, found 216.1136.

Synthesis of l-Methyl-4,5,6,7-tetrahydro-isoindole (77). To a stirred suspension of LiAlH ₄ (1.57 g, 41.45 mmol) in dry THF (50 mL) was added dropwise 53 (2.0 g, 10.36 mmol) in THF (50 mL) at 0 °C. Then the resulting solution was stirred at same temperature for additional 3 h and heated to reflux overnight. The reaction was quenched with saturated solution of sodium sulfate. The insoluble solid was filtrated off, and washed with DCM (100 mL). Then the combined organic solution was concentrated under reduced pressure and the product was chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the desired product 77 (1.19 g, 85%). ^l H NMR (CDC1 ₃ , 400 MHz) δ 7.61 (br s, 1H), 6.47 (d, = 2.8 Hz, 1H), 2.71 (t, = 5.8 Hz, 2H), 2.60 (t, = 6.0 Hz, 2H), 1.90 (s, 3H), 1.87 (m, 4H); ¹³ C NMR (CDC1 , 100 MHz) δ 121.9, 120.1, 115.5, 110.7, 24.2 (2C), 22.3, 21.5, 10.9; HRMS (ESI) calcd for C ₉ Hi ₄ N (M + H) ⁺ 136.1121, found 136.1117.

Synthesis of 3-Methyl-4,5,6,7-tetrahydro-isoindole-l-carboxaldehyde (38).

Compound 38 (917 mg, 76%) was synthesized by the same procedure as described for 55. ^l H

NMR (CDC1 , 400 MHz) δ 10.10 (br s, 1H), 9.37 (s, 1H), 2.82 (t, = 5.8 Hz, 2H), 2.41 (t, =

6.0 Hz, 2H), 2.23 (s, 3H), 1.78 (m, 4H); ¹³ C NMR (CDC1 , 100 MHz) δ 175.0, 135.4, 135.1, 126.5, 120.2, 23.3, 22.8, 21.0, 20.8, 11.3; HRMS (ESI) calcd for CioHi ₄ NO (M + H) ⁺ 164.1070, found 164.1065.

Synthesis of Bis(3-ethyl-4-methyl-lH-pyrrol-2-yl)methane (79). Compound 79 (1.13 g, 92%) was synthesized by the same procedure as described for 54. 1H NMR (CDCb, 400 MHz) δ 7.25 (br s, 2H), 6.26 (t, = 1.2 Hz, 2H), 3.73 (s, 2H), 2.36 (q, = 7.5 Hz, 4H), 1.97 (s, 6H), 1.02 (t, = 7.5 Hz, 6H); HRMS (ESI) calcd for C15H23N2 (M + H) ⁺ 231.1856, found 231.1861.

Synthesis of 5,5'-Methylenebis(4-ethyl-3-methyl-lH-pyrrole-2-carbaldehyde ) (39).

Compound 39 (907 mg, 73%) was synthesized by the same procedure as described for 55. ^l H NMR (CDCb, 400 MHz) δ 11.46 (br s, 2H), 9.48 (s, 2H), 3.86 (s, 2H), 2.31 (q, = 7.4 Hz, 4H), 2.18 (s, 6H), 0.81 (t, = 7.5 Hz, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 176.5, 134.2, 130.0, 127.9, 123.7, 22.4, 16.3, 14.9, 8.4. (Dimer); HRMS (ESI) calcd for C17H23N2O2 (M + H) ⁺ 287.1786, found 287.1782.

Representative Procedure for the Synthesis of Prodiginine (85). To a stirred solution of 6 (250 mg, 1.31 mmol) and 2,4-dialkylpyrrole (80; 829 mg, 2.63 mmol) in anhydrous methanol (50 mL) was added methanolic 2 N HC1 (catalytic amount). The resulting brightly colored solution was stirred for 5 h at room temperature. The methanol was removed under reduced pressure and the product was chromatographed on neutral alumina, with ethyl acetate/hexanes as eluent, to afford the desired prodiginine analogue 85.HC1 (468 mg, 68%) as a bright red colored compound. ^l H NMR (CDCb, 400 MHz) δ 12.85 (br s, 1H), 12.81 (br s, 1H), 12.65 (br s, 1H), 7.30 (d, = 8.1 Hz, 2H), 7.26 (m, 5H), 7.06 (d, = 8.1 Hz, 2H), 7.01 (s, 1H), 6.97 (m, 1H), 6.38 (m, 1H), 6.09 (d, = 1.9 Hz, 1H), 5.87 (d, = 1.6 Hz, 1H), 4.23 (s, 2H), 4.00 (s, 3H), 3.93 (s, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 166.2, 149.1, 148.8, 141.0, 138.3, 136.4, 132.5, 132.2, 130.5 (2C), 129.8 (2C), 128.7 (4C), 127.9, 123.9, 122.1, 121.7, 118.3, 113.4, 112.9, 112.2, 93.1, 58.9, 33.8, 31.9; HRMS (ESI) calcd for C28H ₂₄ C1 ₂ N30 (M + H) ⁺ 488.1291, found 488.1284; IR (KBr) vmax 3320, 3010, 2845, 1510, 1045, 742 cm ^"1 .

Synthesis of 5'-((3,5-Bis(4-chlorobenzyl)-l-methyl-pyrrol-2-yl)methylene) -4'- methoxy-l-methyl-2,2'-bipyrrole (87). To a stirred solution of prodiginine 85 (50 mg, 0.10 mmol) in DMF (10 mL) was added NaH (10 mg, 0.41 mmol) at 0 °C. The resulting bright red suspension was stirred for 10 min, and methyl iodide (58 mg, 0.41 mmol) was added at 0 °C and stirred for additional 30 min. The reaction mixture was warmed to room temperature, and gradually poured into ice cold water and extracted with ethyl acetate (3 x 30 mL). The combined organic layers were washed with water and dried over anhydrous Na2S0 ₄ . The solvent was evaporated under reduced pressure and the product was chromatographed on neutral alumina, with ethyl acetate/hexanes as eluent, to afford the desired prodiginine 87 (46 mg, 85%). ^l H

NMR (CDCh, 400 MHz) δ 7.24 (d, J = 8.3 Hz, 2H), 7.18 (d, J = 8.4 Hz, 2H), 7.11 (d, J = 8.4 Hz, 2H), 7.06 (d, J = 8.3 Hz, 2H), 6.84 (s, 1H), 6.74 (br s, 1H), 6.68 (dd, J = 1.5, 3.8 Hz, 1H), 6.17 (dd, J = 2.6, 3.7 Hz, 1H), 5.92 (s, 1H), 5.75 (s, 1H), 4.25 (s, 2H), 3.96 (s, 3H), 3.90 (s, 3H), 3.89 (s, 2H), 3.63 (s, 3H); ¹³ C NMR (CDCh, 100 MHz) δ 167.8, 161.2, 142.1, 140.7, 136.9, 132.4, 131.6, 130.1 (3C), 129.8 (2C), 129.3, 128.8, 128.7 (3C), 127.8 (2C), 127.2, 115.3, 113.5, 111.7, 108.4, 96.9, 58.4, 37.5, 33.0, 32.7, 29.7; HRMS (ESI) calcd for C30H28CI2N3O (M + H) ⁺ 516.1604, found 516.1607.

Representative Procedure for the Synthesis of Tambjamine (99). To a stirred solution of 6 (100 mg, 0.52 mmol) and n-butylamine (77 mg, 1.05 mmol) in anhydrous methanol (10 mL) was added methanolic 2 N HC1 (catalytic amount). The resulting pale yellow colored solution was stirred at refluxing temperature for 5 h and the solvent was removed under reduced pressure. The crude solid was dissolved in EtOAc (50 mL) and washed with 2 N HC1 (2 x 10 mL). The organic layer was dried over anhydrous Na2S0 ₄ . The solvent was removed under reduced pressure and the product was chromatographed on neutral alumina, with ethyl acetate/hexanes as eluent, to afford the desired tambjamine 99 (117 mg, 91%) as a yellow solid. *H NMR (CDCI3, 400 MHz) δ 7.26 (s, 1H), 6.98 (dd, 7 = 1.3, 2.7 Hz, 1H), 6.67 (dd, = 1.3, 3.6 Hz, 1H), 6.20 (dd, = 2.7, 3.6 Hz, 1H), 5.87 (s, 1H), 3.84 (s, 3H), 3.41 (t, = 7.1 Hz, 2H), 1.67 (m, 2H), 1.37 (m, 2H), 0.89 (t, = 7.3 Hz, 3H); ¹³ C NMR (CDCh, 100 MHz) δ 163.7, 142.2, 140.3, 124.0, 122.7, 113.1, 110.8, 110.7, 91.1, 58.5, 50.7, 32.2, 19.7, 13.6; HRMS (ESI) calcd for Ci ₄ H ₂ oN ₃ 0 (M + H) ⁺ 246.1601, found 246.1605. IR (KBr) v _max 3299, 2936, 1420, 1175, 722 cm ^"1 .

Representative Procedure for the Synthesis of N-(adamantan-l-yl)-2- (((oxoboranyl)methylene)amino)acetamide (188). To a stirred solution of 44 (2.0 g, 11.43 mmol) in a mixture of THF (25 mL) and CH2CI2 (25 mL) were added 1-adamantylamine (2.07 g,

13.71 mmol), DMAP (348 mg, 2.85 mmol), and N-(3-dimethylamino-propyl)-N'- ethylcarbodiimide hydrochloride (EDC1, 2.62 g, 13.71 mmol). The reaction mixture was stirred at room temperature for 4 h. The reaction was quenched with saturated aqueous NH ₄ C1 solution (50 mL) and extracted with ethyl acetate (3 x 100 mL). The combined organic phases were washed with brine and dried over anhydrous Na2S0 ₄ . The solvent was removed under reduced pressure and the product was chromatographed on neutral alumina, with ethyl acetate/hexanes as eluent, to afford the desired product 188 (2.99 g, 85%). ¾ NMR (CDCh, 400 MHz) δ 6.01 (br s, 1H), 5.52 (br s, 1H), 3.64 (d, = 4.7 Hz, 2H), 2.03 (m, 3H), 1.96 (d, = 2.9 Hz, 6H), 1.64 (m, 6H), 1.41 (s, 9H); HRMS (ESI) calcd for C17H29N2O3 (M + H) ⁺ 309.2173, found 309.2180.

Representative Procedure for the Synthesis of N-(Adamantan-l-yl)-2- aminoacetamide (189). Compound 188 (2.5 g, 8.11 mmol) was dissolved in 20 mL of trifluoroacetic acid/water (1 : 1) and stirred at room temperature for 3 h. The reaction mixture was neutralized with 2 N NaOH and extracted with ethyl acetate (3 x 100 mL). The combined organic layers were washed with brine, and dried over anhydrous Na ₂ S0 ₄ . The solvent was removed under reduced pressure to obtain the pure product 189 (1.60 g, 95%) as a white solid. ^l H NMR (CDCI3, 400 MHz) δ 6.88 (br s, 1H), 3.20 (s, 2H), 2.06 (br s, 3H), 1.97 (d, J = 2.8 Hz, 6H), 1.70 (m, 6H); HRMS (ESI) calcd for C12H21N2O (M + H) ⁺ 209.1648, found 209.1646. Note. Two NH protons are not appering under these conditions.

Synthesis of N-(2-((Adamantan-l-yl)amino)-2-oxoethyl)-pyrrole-2-carboxami de (190). Compound 190 (1.09 g, 81%) was synthesized by the same procedure as described for 188. ^l H NMR (CDCI3, 400 MHz) δ 9.83 (br s, 1H), 7.21 (t, J = 5.3 Hz 1H), 6.85 (m, 1H), 6.69 (m, 1H), 6.16 (m, 1H), 6.08 (s, 1H), 3.90 (d, J = 5.3 Hz, 2H), 1.99 (br s, 3H), 1.92 (d, J = 2.6 Hz, 6H), 1.59 (m, 6H); ¹³ C NMR (CDCI3 + CD3OD, 100 MHz) δ 169.1, 162.4, 124.9, 122.2, 111.2, 109.5, 51.0, 43.2, 42.2 (3C), 36.2 (3C), 29.4 (3C); HRMS (ESI) calcd for Ci ₇ H ₂ 3NaN30 ₂ (M + Na) ⁺ 324.1682, found 324.1693.

Synthesis of N ¹ -((Pyrrol-2-yl)methyl)-N ² -(adamantan-l-yl)ethane-l,2-diamine (191). Compound 191 (186 mg, 82%) was synthesized by the same procedure as described for 67a. ^l H NMR (CDCI3, 400 MHz) δ 9.52 (br s, 1H), 6.74 (dd, J = 1.9, 2.7 Hz, 1H), 6.11 (dd, J = 3.0, 5.6 Hz, 1H), 6.02 (d, / = 1.9 Hz, 1H), 3.80 (s, 2H), 3.00 (br s, 2H), 2.76 (m, 4H), 2.08 (br s, 3H), 1.69-1.60 (m, 12H); ¹³ C NMR (CDCI3, 100 MHz) δ 130.1, 117.5, 107.8, 106.4, 51.5, 48.9, 46.1, 42.1 (3C), 39.4, 36.5 (3C), 29.5 (3C); HRMS (ESI) calcd for 0 ₇ Η ₂₈ Ν ₃ (M + H) ⁺ 274.2278, found 274.2287.

Synthesis of 3-(Pyrrol-2-yl)-acrylic acid methyl ester (192). To a stirred suspension of NaH (910 mg, 37.89 mmol) in 50 mL of anhydrous dimethoxyethane at 0 °C was added dropwise a methyl diethylphosphnoacetate (7.96 g, 37.89 mmol). The reaction mixture was stirred at 0 °C for 30 min and then allowed to warm to room temperature. Pyrrole-2- carboxaldehyde (40; 3.0 g, 31.58 mmol) was added and the reaction mixture was stirred for additional 4 h. The reaction was quenched with ice-water and extracted with ethyl acetate (3 x

50 mL). The combined organic layer was washed with brine and dried over anhydrous Na ₂ S0 ₄ .

The solvent was evaporated under reduced pressure and the product was chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the pure product 192 (3.72 g, 78%). Rf value of the product 192 is similar to the starting material 40, the visualization of the product was black spot on TLC after applying the iodine vapor. ^l U NMR (CDC1 ₃ , 600 MHz) δ 9.26 (br s, 1H), 7.61 (d, 7 = 15.9 Hz, 1H), 6.94 (d, 7 = 1.4 Hz, 1H), 6.58 (s, 1H), 6.29 (d, 7 = 3.6 Hz, 1H), 6.10 (d, 7 = 15.9 Hz, 1H), 3.80 (s, 3H). HRMS (ESI) calcd for C ₈ HioN0 ₂ (M + H) ⁺ 152.0706, found 152.0710.

Synthesis of 3-(Pyrrol-2-yl)-acrylic acid (193). To a stirred suspension of 192 (2.0 g, 13.24 mmol) in a mixture of THF (50 mL) and water (60 mL) was added L1OH.H2O (1.66 g, 39.73 mmol). The reaction mixture was stirred at 60 °C for 12 h after which it was cooled to 0 °C and washed with ethyl acetate (3 x 30 mL). The aqueous layer was carefully acidified to pH 2 with 2 N HCl and extracted with ethyl acetate (3 x 50 mL). The combined extracts were dried over anhydrous Na ₂ S0 ₄ , and concentrated under reduced pressure to give the pure product 193 (1.74 g 96%). ^l H NMR (CD3OD, 600 MHz) δ 7.51 (d, 7 = 15.8 Hz, 1H), 6.91 (dd, 7 = 1.1, 2.3 Hz, 1H), 6.49 (dd, 7 = 1.1, 3.5 Hz, 1H), 6.18 (dd, 7 = 2.2, 4.9 Hz, 1H), 6.04 (d, 7 = 15.8 Hz, 1H); HRMS (ESI) calcd for C ₇ H ₇ NaN0 ₂ (M + Na) ⁺ 160.0369, found 160.0363. Note. NH and COOH protons are not appearing under these conditions.

Synthesis of N-(2-Adamantan-l-yl)amino)-2-oxoethyl)-3-(pyrrol-2-yl)acryla mide (194). Compound 194 (2.02 g, 85%) was synthesized by the same procedure as described for 188. ^l H NMR (DMSO- 600 MHz) δ 11.34 (s, 1H), 7.95 (t, 7 = 5.8 Hz, 1H), 7.27 (d, 7 = 15.7 Hz, 1H), 7.26 (s, 1H), 6.91 (dd, 7 = 2.4, 3.7 Hz, 1H), 6.41 (s, 1H), 6.26 (d, 7 = 15.7 Hz, 1H), 6.12 (dd, 7 = 2.4, 5.6 Hz, 1H), 3.71 (d, 7 = 5.8 Hz, 2H), 1.99 (s, 3H), 1.92 (d, 7 = 2.7 Hz, 6H), 1.61 (m, 6H); ¹³ C NMR (DMSC fc, 100 MHz) δ 167.9, 165.9, 129.8, 128.5, 121.6, 114.9, 111.5, 109.5, 50.7, 42.5, 41.0 (3C), 36.0 (3C), 28.8 (3C); HRMS (ESI) calcd for CwEzsNaNaCfc (M + Na) ⁺ 350.1839, found 350.1853.

Representative Procedure for the Synthesis of 195. To a stirred solution of 194 (500 mg, 1.52 mmol) in methanol (10 mL) at room temperature was added NiCl ₂ .6H ₂ 0 (180 mg, 0.76 mmol). When the clear solution acquired a greenish color, the whole reaction mixture was brought to 0 °C and NaBH ₄ (85 mg, 2.29 mmol) was added portion-wise. The black colored reaction mixture was stirred for 30 min at 0 °C, and the solvent was removed under reduced pressure. The crude product was dissolved in ethyl acetate (50 mL), and treated with aqueous

NH ₄ C1 (2 x 10 mL). The organic layer was washed with brine and dried over anhydrous

Na ₂ S0 ₄ . The organic solvent was evaporated under reduced pressure and the product was chromatographed on silica gel, with ethyl acetate/hexanes as eluent, to afford the desired product 195 (473 mg, 94%) as a white solid. ^l H NMR (DMSO-ifc, 600 MHz) δ 11.50 (s, 1H), 7.97 (t, 7= 5.8 Hz, 1H), 7.24 (s, 1H), 6.55 (dd, 7 = 2.3, 3.9 Hz, 1H), 5.86 (dd, 7= 2.6, 5.4 Hz, 1H), 5.72 (s, 1H), 3.62 (d, 7= 5.8 Hz, 2H), 2.75 (t, 7= 7.4 Hz, 2H), 2.41 (t, 7= 7.4 Hz, 2H), 2.00 (br s, 3H), 1.91 (d, 7 = 2.6 Hz, 6H), 1.60 (br s, 6H); ¹³ C NMR (DMSO-ifc, 100 MHz) δ 171.8, 167.9, 130.8, 116.0, 107.0, 104.2, 50.7, 42.3, 41.0 (3C), 35.9 (3C), 35.3, 28.8 (3C), 23.2; HRMS (ESI) calcd for C19H28N3O2 (M + H) ⁺ 330.2176, found 330.2169.

Synthesis of N ¹ -(3-(Pyrrol-2-yl)propyl)-N ² -(adamantan-l-yl)ethane-l,2-diamine (196). Compound 196 (178 mg, 78%) was synthesized by the same procedure as described for 67a. ^l H NMR (CDCI3, 400 MHz) δ 9.28 (br s, 1H), 6.68 (s, 1H), 6.12 (t, 7 = 2.8 Hz, 1H), 5.92 (m, 1H), 2.78-2.66 (m, 8H), 2.16 (br s, 2H), 2.09 (br s, 3H), 1.83 (m, 2H), 1.86-1.67 (m, 12H); ¹³ C NMR (CDCI3, 100 MHz) δ 132.1, 116.2, 107.9, 104.9, 50.1, 50.0, 48.9, 42.6 (3C), 39.6, 36.7 (3C), 29.6 (4C), 25.6; HRMS (ESI) calcd for C19H32N3 (M + H) ⁺ 302.2591, found 302.2587.

Compound characterization data

5'-((3,5-Bis(4-chlorobenzyl)-pyrrol-2-yl)methylene)-4'-metho xy-l-methyl~2,2'- bipyrrole (86)

^X H NMR (CDCI3, 400 MHz) δ 7.25-7.21 (m, 4H), 7.13 (m, 4H), 6.76 (s, 1H), 6.72 (t, 7 = 2.0 Hz, 1H), 6.64 (dd, 7 = 1.7, 3.9 Hz, 1H), 6.61 (dd, 7 = 2.6, 3.9 Hz, 1H), 5.87 (s, 1H), 5.80 (s, 1H), 3.91 (s, 2H), 3.90 (s, 2H), 3.84 (s, 3H), 3.72 (s, 3H); ¹³ C NMR (CDCI3, 100 MHz) δ 167.2, 159.2, 142.1, 139.9, 137.3, 137.1, 132.5, 131.7, 130.6, 130.0 (2C), 129.9 (2C), 128.8 (2C), 128.6, 128.5 (3C), 128.4, 115.0, 111.8, 111.0, 108.5, 96.8, 58.3, 37.3, 34.1, 31.5; HRMS (ESI) calcd for C29H26CI2N3O (M + H) ⁺ 502.1447, found 502.1468.

5'-((3,5-Bis(4-chlorobenzyl)-l-methyl-pyrrol-2-yl)methylene) -4'-methoxy-l-methyl- 2,2'-bipyrrole (87)

lH NMR (CDCI3, 400 MHz) δ 7.24 (d, 7 = 8.3 Hz, 2H), 7.18 (d, 7 = 8.4 Hz, 2H), 7.11 (d, 7 = 8.4 Hz, 2H), 7.06 (d, 7 = 8.3 Hz, 2H), 6.84 (s, 1H), 6.74 (br s, 1H), 6.68 (dd, 7 = 1.5, 3.8 Hz, 1H), 6.17 (dd, J = 2.6, 3.7 Hz, IH), 5.92 (s, IH), 5.75 (s, IH), 4.25 (s, 2H), 3.96 (s, 3H), 3.90 (s, 3H), 3.89 (s, 2H), 3.63 (s, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 167.8, 161.2, 142.1, 140.7, 136.9, 132.4, 131.6, 130.1 (3C), 129.8 (2C), 129.3, 128.8, 128.7 (3C), 127.8 (2C), 127.2, 115.3, 113.5, 111.7, 108.4, 96.9, 58.4, 37.5, 33.0, 32.7, 29.7; HRMS (ESI) calcd for C30H28CI2N3O (M + H) ⁺ 516.1604, found 516.1607.

5'-((3,5-Bis(4-chlorobenzyl)-pyrrol-2-yl)methylene)-4'-(4-ch lorophenyl)-2,2'- bipyrrole hydrochloride (88)

^! H NMR (CDCb, 400 MHz) δ 13.31 (s, IH), 13.20 (s, IH), 12.57 (s, IH), 7.32 (d, / = 8.6 Hz, 2H), 7.27 (d, / = 8.4 Hz, 2H), 7.21 (d, / = 8.5 Hz, 2H), 7.18 (s, IH), 7.14 (m, 2H), 7.09 (d, = 8.4 Hz, 2H), 6.93 (br s, IH), 6.85 (d, / = 8.5 Hz, 2H), 6.76 (s, IH), 6.68 (s, IH), 6.31 (br s, IH), 5.96 (s, IH), 4.23 (s, 2H), 3.76 (s, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 152.3, 149.3, 147.2, 144.1, 137.8, 135.7, 132.8, 132.4, 130.8, 130.6, 130.5 (2C), 129.6 (2C), 129.2 (2C), 128.9 (3C), 128.8 (3C), 128.3, 127.9, 125.9, 122.0, 119.8, 118.1, 115.6, 115.1, 112.3, 34.0, 32.3; HRMS (ESI) calcd for C33H25CI3N3 (M + H) ⁺ 568.1109, found 568.1128.

5'-((5-Undecyl-pyrrol-2-yl)methylene)-2,2'-bipyrrole (89)

^X H NMR (MeOD, 400 MHz) δ 7.42 (m, 2H), 7.35 (s, IH), 7.25 (m, IH), 7.21 (m, IH), 7.08 (m IH), 6.41 (m, 2H), 2.53 (t, = 7.6 Hz, 2H), 1.74 (m, 2H), 1.28 (m, 16H), 0.84 (t, = 6.7 Hz, 3H); HRMS (ESI) calcd for C24H ₃₄ N ₃ (M + H) ⁺ 364.2747, found 364.2760.

4'-Ethyl-5'-((5-undecyl-pyrrol- -yl)methylene)-2,2'-bipyrrole hydrochloride (90)

lH NMR (CDCb, 400 MHz) δ 13.05 (br s, 2H), 12.73 (br s, IH), 7.25 (br s, IH), 6.99 (br s, IH), 6.90 (br s, 2H), 6.68 (s, IH), 6.37 (br s, IH), 6.26 (br s, IH), 2.99 (t, = 7.6 Hz, 2H), 2.72 (q, = 7.6 Hz, 2H), 1.79 (m, 2H), 1.37 (t, = 7.6 Hz, 3H), 1.27 (m, 16H), 0.89 (t, = 6.8 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 155.1, 153.8, 148.3, 130.8, 129.2, 127.6, 127.0, 122.1, 118.9, 117.9, 114.5, 113.4, 112.0, 31.9, 29.6 (3C), 29.4 (2C), 29.3, 29.2, 22.7 (2C), 19.7, 14.1 (2C); HRMS (ESI) calcd for C ₂ 6H ₃₈ N (M + H) ⁺ 392.3060, found 392.3072.

3'-Isopropyl-5'-((5-undecyl-pyrrol-2-yl)methylene)-2,2'-bipy rrole hydrochloride

(91)

lH NMR (CDCb, 400 MHz) δ 13.35 (br s, 1H), 12.93 (br s, 2H), 7.28 (m, 1H), 7.08 (m, 1H), 6.98 (d, = 1.9 Hz, 1H), 6.93 (dd, = 2.3, 4.0 Hz, 1H), 6.86 (s, 1H), 6.41 (m, 1H), 6.28 (dd, = 1.6, 4.0 Hz, 1H), 3.24 (m, 1H), 2.99 (t, = 7.6 Hz, 2H), 1.81-1.77 (m, 2H), 1.43-1.23 (m, 22H), 0.88 (t, = 6.8 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 158.4, 146.6, 139.5, 133.2, 131.7, 129.2, 127.8, 126.7, 122.7, 121.7, 117.7, 114.1, 112.2, 31.9, 29.6 (2C), 29.6, 29.4, 29.3, 29.1, 28.6, 26.1, 22.7 (4C), 14.1; HRMS (ESI) calcd for C ₂ 7H ₄₀ N ₃ (M + H) ⁺ 406.3217, found

406.3231.

3 ' -(tert-Butyl)-5 ' -((5-undecyl-pyrrol-2-yl)methylene)-2,2' -bipyrrole hydrochloride

(92)

lH NMR (CDCb, 400 MHz) δ 13.33 (br s, 1H), 12.65 (br s, 1H), 12.24 (br s, 1H), 7.27 (s, 1H), 7.01 (m, 1H), 6.90 (d, = 3.7 Hz, 1H), 6.82 (dd, = 2.3, 4.0 Hz, 1H), 6.73 (m, 1H), 6.33 (dd, = 2.5, 3.8 Hz, 1H), 6.21 (d, = 3.7 Hz, 1H), 2.96 (t, = 7.6 Hz, 2H), 1.74 (m, 2H), 1.37 (s. 9H), 1.25 (m, 16H), 0.81 (t, = 6.8 Hz, 3H); HRMS (ESI) calcd for C ₂ 8H ₄₂ N (M + H) ⁺ 420.3373, found 420.3385.

3 ' -Chloro-4' -ethyl-5 ' -((5-undecyl-pyrrol-2-yl)methylene)-2,2' -bipyrrole (93)

^! H NMR (MeOD, 400 MHz) δ 7.17 (dd, / = 1.3, 3.7 Hz, 1H), 7.01 (dd, = 1.3, 2.9 Hz, 1H), 6.82 (s, 1H), 6.65 (d, = 3.7 Hz, 1H), 6.25 (dd, = 2.9, 3.7 Hz, 1H), 6.04 (d, = 3.7 Hz, 1H), 2.79 (q, = 7.6 Hz, 2H), 2.65 (t, = 7.6 Hz, 2H), 1.71 (m, 2H), 1.26 (m, 16H), 1.20 (t, = 7.6 Hz, 3H), 0.88 (t, = 6.6 Hz, 3H). HRMS (ESI) calcd for C ₂ 6H ₃₇ C1N (M + H) ⁺ 426.2671, found 426.2688. 3 ' -Ethyl-4' -methyl-5 ' -((5-undecyl-pyrrol-2-yl)methylene)-2,2' -bipyrrole (94)

lH NMR (CDCb, 400 MHz) δ 6.86 (br s, 1H), 6.78 (d, = 3.0 Hz, 1H), 6.68 (s, 1H), 6.58 (d, = 3.6 Hz, 1H), 6.29 (br s, 1H), 5.94 (d, = 2.7 Hz, 1H), 2.68 (q, = 7.5 Hz, 2H), 2.51 (br s, 2H), 2.17 (s, 3H), 1.58 (br s, 2H), 1.25 (m, 16H), 1.17 (t, J = 7.6 Hz, 3H), 0.87 (t, J = 6.6 Hz, 3H). HRMS (ESI) calcd for C27H40N3 (M + H) ⁺ 406.3217, found 406.3235.

3 ' -Ethyl-4' -methyl-5 ' -((5-octyl-pyrrol-2-yl)methylene)-2,2' -bipyrrole hydrochloride

(95)

lH NMR (CDCb, 400 MHz) δ 13.32 (br s, 1H), 13.02 (br s, 1H), 12.72 (s, 1H), 7.27 (s, 1H),

7.05 (d, J = 2.4 Hz, 1H), 6.89 (m, 2H), 6.39 (m, 1H), 6.23 (dd, J = 1.4, 3.7 Hz, 1H), 2.96 (t, J =

7.6 Hz, 2H), 2.72 (q, = 7.5 Hz, 2H), 2.25 (s, 3H), 1.77 (m, 2H), 1.29 (m, 10H), 1.18 (t, J = 7.5 Hz, 3H), 0.88 (t, = 6.7 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 154.8, 146.8, 144.2, 131.2, 130.7, 129.1, 127.2, 126.8, 121.6, 119.0, 117.6, 113.3, 112.2, 31.8, 29.4 (2C), 29.2 (2C), 28.5, 22.7, 18.6, 14.1, 13.3, 9.9. HRMS (ESI) calcd for C24H34N3 (M + H) ⁺ 364.2747, found

364.2762.

3 ' -Ethyl-4' -methyl-5 ' -((3-octyl-pyrrol-2-yl)methylene)-2,2' -bipyrrole (96)

^X H NMR (CDCb, 400 MHz) δ 6.89 (br s, 1H), 6.81 (br s, 2H), 6.75 (s, 1H), 6.29 (s, 1H), 6.05 (br s, 1H), 2.71 (q, = 7.5 Hz, 2H), 2.60 (t, = 7.5 Hz, 2H), 2.20 (s, 3H), 1.55 (m, 2H), 1.25 (m, 10H), 1.18 (t, / = 7.5 Hz, 3H), 0.88 (t, = 6.7 Hz, 3H). HRMS (ESI) calcd for C24H34N3 (M + H) ⁺ 364.2747, found 364.2765.

3'-Ethyl-5'-((3-(4-fluorobenzyl)-5-heptyl-pyrrol-2-yl)methyl ene)-4'-methyl-2,2'- bipyrrole (97) ^l H NMR (CDCb, 400 MHz) δ 7.11 (m, 2H), 6.94 (m, 2H), 6.78 (m, IH), 6.71 (s, IH), 6.65 (m, IH), 6.61 (m, IH), 5.65 (s, IH), 3.91 (s, 2H), 2.72 (q, 7 = 7.5 Hz, 2H), 2.26 (s, 3H), 2.21 (t, 7 = 7.6 Hz, 2H), 1.35-1.12 (m, 13H), 0.86 (t, 7 = 6.7 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 162.5, 160.1, 159.7, 146.0, 143.7, 142.1, 136.9, 135.9, 133.5, 129.9, 129.8, 127.9, 126.7, 121.6, 115.2, 115.0, 114.9, 112.0, 110.3, 109.8, 31.8, 29.5, 29.1, 28.8, 27.4, 22.7, 18.9, 14.4, 14.1, 9.6; HRMS (ESI) calcd forC3oH ₃₇ FN3 (M + H) ⁺ 458.2966, found 458.3000.

5 ' -((3,5-Bis(4-chlorobenzyl)-pyrrol-2-yl)methylene)-3 ' -ethyl-4' -methyl-2,2' - bipyrrole hydrochloride (98)

lH NMR (CDCb, 400 MHz) δ 13.34 (br s, IH), 12.98 (br s, IH), 12.57 (br s, IH), 7.33 (m, 7H), 7.09 (m, 3H), 6.82 (s, IH), 6.41 (m, IH), 5.97 (s, IH), 4.30 (s, 2H), 3.99 (s, 2H), 2.75 (q, 7 = 7.5 Hz, 2H), 2.17 (s, 3H), 1.12 (t, 7 = 7.5 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 150.3, 147.2, 144.2, 142.3, 138.3, 136.2, 132.6, 132.4, 131.5, 130.5 (2C), 129.8 (2C), 129.2, 128.9 (2C), 128.8 (2C), 127.4, 125.0, 121.6, 118.1, 115.7, 114.4, 112.5, 33.8, 32.4, 18.7, 13.3, 9.8. HRMS (ESI) calcd for C30H28CI2N3 (M + H) ⁺ 500.1655, found 500.1685.

Ν-((4' -Methoxy- [2,2' -bipyrrol] -5 ' -ylidene)methyl)butan-l-amine (99)

^X H NMR (CDCb, 400 MHz) δ 7.26 (s, IH), 6.98 (dd, 7 = 1.3, 2.7 Hz, IH), 6.67 (dd, 7 = 1.3, 3.6 Hz, IH), 6.20 (dd, 7 = 2.7, 3.6 Hz, IH), 5.87 (s, IH), 3.84 (s, 3H), 3.41 (t, 7 = 7.1 Hz, 2H), 1.67 (m, 2H), 1.37 (m, 2H), 0.89 (t, 7 = 7.3 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 163.7, 142.2, 140.3, 124.0, 122.7, 113.1, 110.8, 110.7, 91.1, 58.5, 50.7, 32.2, 19.7, 13.6; HRMS (ESI) calcd for Ci ₄ H ₂ oN ₃ 0 (M + H) ⁺ 246.1601, found 246.1605.

_V-((4' -Methoxy- [2,2' -bipyrrol] -5 ' -ylidene)methyl)hexan- 1-amine (100)

lH NMR (CDCb, 400 MHz) δ 7.25 (s, IH), 6.96 (dd, 7 = 1.3, 2.7 Hz, IH), 6.67 (dd, 7 = 1.3, 3.6 Hz, IH), 6.19 (dd, 7 = 2.7, 3.6 Hz, IH), 5.88 (s, IH), 3.83 (s, 3H), 3.39 (t, 7 = 7.2 Hz, 2H), 1.68 (m, 2H), 1.34-1.17 (m, 6H), 0.82 (t, 7 = 7.2 Hz 3H); ¹³ C NMR (CDCb, 100 MHz) δ 163.7, 142.2, 140.3, 123.9, 122.7, 113.0, 110.8, 110.7, 91.1, 58.5, 51.0, 31.2, 30.2, 26.1, 22.4, 14.0; HRMS (ESI) calcd for Ci ₆ H ₂₄ N ₃ 0 (M + H) ⁺ 274.1914, found 274.1911.

N- ((4 ' -Methoxy- [2,2 ' -bipyrrol] -5 ' -ylidene)methyl)octan- 1 -amine hydrochloride

(101)

^X H NMR (CDCb, 400 MHz) δ 13.57 (s, IH), 10.55 (s, IH), 9.65 (s, IH), 7.25 (d, = 14.8 Hz IH), 6.98 (m, IH), 6.67 (m, IH), 6.20 (m, IH), 5.87 (d, / = 1.9 Hz, IH), 3.84 (s, 3H), 3.41 (m, 2H), 1.68 (m, 2H), 1.33-1.19 (m, 10H), 0.80 (t, / = 6.7 Hz 3H); ¹³ C NMR (CDCb, 100 MHz) δ 163.7, 142.2, 140.3, 124.1, 122.7, 113.1, 110.8, 110.7, 91.1, 58.5, 51.0, 31.7, 30.3, 29.1 (2C), 26.5, 22.6, 14.1 ; HRMS (ESI) calcd for Ci ₈ H ₂₈ N 0 (M + H) ⁺ 302.2227, found 302.2236.

N- ((4 ' -Methoxy- [2,2 ' -bipyrrol] -5 ' -ylidene)methyl)undecan- 1 -amine hydrochloride

(102)

lH NMR (CDCb, 400 MHz) δ 7.25 (d, = 14.9 Hz, IH), 6.96 (dd, = 2.5, 3.7 Hz, IH), 6.67 (m, IH), 6.19 (m, IH), 5.87 (s, IH), 3.83 (s, 3H), 3.40 (m, 2H), 1.67 (m, 2H), 1.32-1.18 (m, 16H), 0.80 (t, = 6.6 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 163.7, 142.2, 140.3, 124.0, 122.7, 113.1, 110.7 (2C), 91.1, 58.5, 51.0, 31.9, 30.3, 29.5 (2C), 29.4, 29.3, 29.1, 26.5, 22.7, 14.1 ; HRMS (ESI) calcd for C ₂ iH ₃₄ N 0 (M + H) ⁺ 344.2696, found 344.2698.

N- ((4 ' -Methoxy- [2,2 ' -bipyrrol] -5 ' -ylidene)methyl)cyclopropanamine (103)

^X H NMR (CDCb, 400 MHz) δ 7.37 (s, IH), 6.99 (m, IH), 6.68 (m, IH), 6.21 (m, IH), 5.87 (s, IH), 3.85 (s, 3H), 2.95 (m, IH), 0.90-086 (m, 4H); ¹³ C NMR (CDCb, 100 MHz) δ 163.9, 142.9, 140.3, 124.4, 122.6, 113.5, 111.3, 110.8, 91.3, 58.5, 31.1, 6.9 (2C); HRMS (ESI) calcd for

Ci Hi ₆ N 0 (M + H) ⁺ 230.1288, found 230.1290.

N-((4' -Methoxy- [2,2' -bipyrrol] -5 ' -ylidene)methyl)cyclobutanamine (104) ^X H NMR (CDCb, 400 MHz) δ 7.23 (d, 7 = 15.9 Hz, 1H), 7.00 (d, 7 = 1.0 Hz, 1H), 6.67 (dd, 7 = 1.0, 3.6 Hz, 1H), 6.21 (dd, J = 2.4, 3.6 Hz, 1H), 5.87 (s, 1H), 3.97 (m, 1H), 3.85 (s, 3H), 2.30 (m, 4H), 1.79-1.66 (m, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 163.8, 142.4, 137.9, 124.2, 122.7, 113.2, 110.8, 110.7, 91.2, 58.5, 55.0, 30.8 (2C), 14.7; HRMS (ESI) calcd for Ci ₄ Hi ₈ N ₃ 0 (M + H) ⁺ 244.1444, found 244.1446.

N-((4' -Methoxy- [2,2' -bipyrrol] -5 ' -ylidene)methyl)cyclopentanamine (105)

lH NMR (CDCb, 400 MHz) δ 7.37 (d, 7 = 15.7 Hz, 1H), 7.03 (dd, 7 = 1.3, 2.6 Hz, 1H), 6.75 (dd, 7 = 1.3, 3.7 Hz, 1H), 6.26 (dd, 7 = 2.6, 3.7 Hz, 1H), 5.97 (s, 1H), 3.93 (m, lH), 3.90 (s, 3H), 2.05 (m, 2H), 1.90 (m, 4H), 1.65 (m, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 163.5, 141.9, 139.0, 123.8, 122.7, 112.9, 110.7, 110.6, 91.1, 62.3, 58.5, 33.5 (2C), 23.6 (2C); HRMS (ESI) calcd for Ci ₅ H ₂ oN 0 (M + H) ⁺ 258.1601, found 258.1607.

N-((4' -Methoxy- [2,2' -bipyrrol] -5 ' -ylidene)methyl)cyclohexanamine (106)

lH NMR (CDCb, 400 MHz) δ 7.31 (d, 7 = 16.4 Hz, 1H), 7.03 (dd, 7 = 2.6, 3.9 Hz, 1H), 6.74 (m, 1H), 6.26 (m, 1H), 5.96 (d, 7 = 2.3 Hz, 1H), 3.90 (s, 3H), 3.37 (m, 1H), 2.06 (m, 2H), 1.87 (m, 2H), 1.61 (m, 3H), 1.35 (m, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 163.6, 141.9, 138.3, 123.9, 122.7, 112.9, 110.7, 110.6, 91.1, 59.6, 58.4, 33.2 (2C), 24.8, 24.5 (2C). HRMS (ESI) calcd for Ci ₆ H ₂₂ N 0 (M + H) ⁺ 272.1757, found 272.1768.

N-((4' -Methoxy- [2,2' -bipyrrol] -5 ' -ylidene)methyl)cycloheptanamine (107)

lH NMR (CDCb, 400 MHz) δ 7.39 (d, 7 = 16.5 Hz, 1H), 7.03 (dd, 7 = 1.2, 3.6 Hz, 1H), 6.73 (m, 1H), 6.26 (dd, 7 = 1.2, 2.4 Hz, 1H), 5.96 (d, 7 = 2.3 Hz, 1H), 3.90 (s, 3H), 3.58 (m, 1H), 2.07 (m, 2H), 1.83 (m, 4H), 1.62 (m, 4H), 1.49 (m, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 163.5, 141.9, 138.5, 123.9, 122.8, 112.9, 110.6 (2C), 91.1, 62.4, 58.4, 35.5 (2C), 27.8 (2C), 23.6 (2C); HRMS (ESI) calcd for Ci ₇ H ₂₄ N 0 (M + H) ⁺ 286.1914, found 286.1923. N-((4' -Methoxy- [2,2' -bipyrrol] -5 ' -ylidene)methyl)cyclooctanamine hydrochloride

(108)

lH NMR (CDCb, 400 MHz) δ 13.57 (br s, 1H), 10.63 (s, 1H), 9.47 (br s, 1H), 7.30 (br s, 1H), 6.97 (s, 1H), 6.65 (d, / = 2.8 Hz, 1H), 6.18 (dd, = 2.8, 3.4 Hz, 1H), 5.88 (s, 1H), 3.83 (s, 3H), 3.53 (m, 1H), 1.93-1.84 (m, 4H), 1.77-1.71 (m, 2H), 1.57-1.43 (m, 8H); ¹³ C NMR (CDCb, 100 MHz) δ 163.5, 141.9, 138.5, 123.9, 122.8, 112.8, 110.6 (2C), 91.0, 61.6, 58.4, 32.5 (2C), 27.0 (2C), 25.3, 23.3 (2C); HRMS (ESI) calcd for CisHieNsO (M + H) ⁺ 300.2070, found 300.2080.

N-((4' -Methoxy- [2,2' -bipyrrol] -5 ' -ylidene)methyl)adamantan-l-amine

hydrochloride (109)

^X H NMR (CDCb, 600 MHz) δ 7.38 (s, 1H), 6.98 (dd, = 0.9, 1.8 Hz, 1H), 6.64 (dd, / = 0.9, 2.5 Hz, 1H), 6.19 (dd, = 1.8, 2.5 Hz, 1H), 5.87 (s, 1H), 3.84 (s, 3H), 2.14 (br s, 3H), 1.91 (d, = 2.8 Hz, 6H), 1.65 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 163.3, 141.7, 135.5, 123.9, 122.8, 112.7, 110.8, 110.5, 91.0, 58.4, 56.1, 42.5 (3C), 35.6 (3C), 29.3 (3C); HRMS (ESI) calcd for C20H26N3O (M + H) ⁺ 324.2070, found 324.2072.

4 ' -Methoxy-5 ' - (piperidin- 1 -ylmethylene) -2,2 ' -bipyrrole (110)

^X H NMR (CD3OD, 400 MHz) δ 7.62 (br s, 1H), 7.06 (br s, 1H), 6.95 (br s, 1H), 6.42 (s, 1H), 6.29 (t, = 3.0 Hz, 1H), 4.00 (s, 3H), 3.96 (br s, 2H), 3.74 (br s, 2H), 1.78 (m, 6H); ¹³ C NMR (CD3OD, 100 MHz) δ 167.9, 145.3, 141.1, 124.6, 123.4, 114.0, 111.8, 109.5, 93.2, 59.4, 45.7 (2C), 24.0, 23.8, 23.5; HRMS (ESI) calcd for C15H20N3O (M + H) ⁺ 258.1601, found 258.1599.

l-Benzyl-N-((4' -methoxy- [2,2' -bipyrrol] -5 ' -ylidene)methyl)piperidin-4-amine (111)

^l H NMR (CDCb, 400 MHz) δ 7.34-7.27 (m, 6H), 7.07 (s, 1H), 6.76 (dd, 7 = 1.6, 3.6 Hz, 1H), 6.28 (br s, 1H), 5.96 (s, 1H), 3.92 (s, 3H), 3.56 (s, 2H), 3.45 (m, 1H), 2.99 (d, J = 11.5 Hz, 2H), 2.18 (m, 2H), 2.05 (m, 2H), 1.94 (m, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 163.8, 142.5, 138.0, 129.1 (2C), 128.3 (4C), 127.2, 124.2, 122.7, 113.2, 111.1, 110.7, 91.2, 62.6, 58.5, 57.3, 51.3, 32.2 (2C); HRMS (ESI) calcd for C ₂ 2H ₂₇ N ₄ 0 (M + H) ⁺ 363.2179, found 363.2194.

4-Chloro-N-((4'-methoxy-[2,2'-bipyrrol]-5'-ylidene)methyl)an iline (112)

lH NMR (MeOD, 400 MHz) δ 7.94 (s, 1H), 7.23 (d, = 8.7 Hz, 2H), 7.14 (d, = 8.7 Hz, 2H), 6.90 (m, 1H), 6.70 (dd, = 0.9, 3.6 Hz, 1H), 6.16 (dd, = 2.4, 3.6 Hz, 1H), 6.14 (s, 1H), 3.84 (s, 3H); ¹³ C NMR (MeOD, 100 MHz) δ 164.2, 137.7, 131.4, 130.7 (3C), 129.8, 124.3, 121.0 (2C), 117.5, 115.5, 112.0, 111.7, 92.9, 59.2; HRMS (ESI) calcd for C16H15CIN3O (M + H) ⁺ 300.0898, found 300.0911.

N-((4'-(4-Chlorophenyl)-[2,2'-bipyrrol]-5'-ylidene)methyl)he xan-l-amine (113)

lH NMR (CDCb, 400 MHz) δ 7.39 (d, = 7.4 Hz, 2H), 7.36 (s, 1H), 7.26 (d, = 7.4 Hz, 2H), 6.94 (dd, = 1.3, 2.6 Hz, 1H), 6.66 (dd, = 1.3, 3.6 Hz, 1H), 6.50 (s, 1H), 6.21 (dd, = 2.6, 3.6 Hz, 1H), 3.46 (t, = 7.2 Hz, 2H), 1.69 (m, 2H), 1.34-1.21 (m, 6H), 0.81 (t, = 6.4 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 146.7, 142.2, 139.7, 134.9, 131.5, 130.1 (2C), 129.3 (2C), 123.1, 122.7, 120.3, 111.8, 110.6, 109.4, 53.3, 31.3, 30.2, 26.3, 22.5, 14.0; HRMS (ESI) calcd for C ₂ iH ₂₅ ClN ₃ (M + H) ⁺ 354.1731, found 354.1725.

N-((4'-(4-Chlorophenyl)-[2,2'-bipyrrol]-5'-ylidene)methyl)un decan-l-amine (114)

lH NMR (CDCb, 400 MHz) δ 7.38 (d, = 7.5 Hz, 2H), 7.24 (d, = 7.5 Hz, 2H), 7.22 (s, 1H), 6.98 (dd, = 1.3, 2.6 Hz, 1H), 6.70 (dd, = 1.3, 3.6 Hz, 1H), 6.54 (s, 1H), 6.22 (dd, = 2.6, 3.6 Hz, 1H), 3.46 (t, = 7.4 Hz, 2H), 1.70 (m, 2H), 1.34-1.17 (m, 16H), 0.81 (t, = 6.4 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 146.2, 144.4, 141.7, 135.2, 131.2, 130.2 (2C), 129.3 (2C), 123.8, 122.5, 119.4, 112.8, 110.7, 110.2, 52.0, 31.9, 30.1, 29.7, 29.6, 29.4, 29.3, 29.1, 26.6, 22.7, 14.1 ; HRMS (ESI) calcd for C26H35CIN3 (M + H) ⁺ 424.2514, found 424.2505.

N-((4'-(4-Chlorophenyl)-[2,2'-bipyrrol]-5'-ylidene)methyl)cy clopentanamine (115)

lH NMR (CDCb, 400 MHz) δ 7.34 (d, = 7.6 Hz, 2H), 7.28 (s, 1H), 7.26 (d, = 7.6 Hz, 2H), 6.97 (dd, / = 1.3, 2.6 Hz, 1H), 6.68 (dd, / = 1.3, 3.6 Hz, 1H), 6.52 (s, 1H), 6.21 (dd, / = 2.6, 3.6 Hz, 1H), 3.87 (m, 1H), 1.99 (m, 2H), 1.85 (m, 4H), 1.62 (m, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 144.8, 143.7, 140.9, 135.1, 131.2, 130.1 (2C), 129.3 (2C), 123.7, 122.6, 119.5, 112.5, 110.7, 109.9, 63.9, 33.6 (2C), 23.8 (2C); HRMS (ESI) calcd for C20H21CIN3 (M + H) ⁺ 338.1418, found 338.1426.

N-((4'-(4-Chlorophenyl)-[2,2'-bipyrrol]-5'-ylidene)methyl)cy clohexanamine (116)

lH NMR (CDCb, 400 MHz) δ 7.40 (s, 1H), 7.35 (d, = 7.6 Hz, 2H), 7.25 (d, = 7.6 Hz, 2H), 6.95 (dd, = 1.4, 2.6 Hz, 1H), 6.65 (dd, = 1.4, 3.7 Hz, 1H), 6.50 (s, 1H), 6.21 (dd, = 2.6, 3.7 Hz, 1H), 3.30 (m, 1H), 1.92 (m, 2H), 1.79 (m, 2H), 1.57 (m, 2H), 1.24 (m, 4H); ¹³ C NMR (CDCb, 100 MHz) δ 144.6, 142.4, 139.9, 134.9, 131.5, 130.1 (2C), 129.3 (2C), 123.2, 122.8, 120.2, 111.8, 110.6, 109.5, 62.1, 33.3 (2C), 24.7, 24.6 (2C); HRMS (ESI) calcd for C21H23CIN3 (M + H) ⁺ 352.1575, found 352.1583.

N-((4'-(4-Chlorophenyl)-[2,2'-bipyrrol]-5'-ylidene)methyl)cy cloheptanamine (117)

^X H NMR (CDCb, 400 MHz) δ 7.37 (d, = 7.4 Hz, 2H), 7.34 (s, 1H), 7.25 (d, = 7.3 Hz, 2H),

6.95 (dd, = 1.3, 2.6 Hz, 1H), 6.67 (dd, = 1.3, 3.7 Hz, 1H), 6.51 (s, 1H), 6.20 (dd, = 2.6, 3.6

Hz, 1H), 3.50 (m, 1H), 1.95 (m, 2H), 1.84-1.71 (m, 4H), 1.53 (m, 4H), 1.41 (m, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 144.5, 142.6, 140.0, 134.9, 131.4, 130.1 (2C), 129.3 (2C), 123.2, 122.7, 119.9, 111.9, 110.6, 109.5, 64.7, 35.5 (2C), 27.8 (2C), 23.8 (2C); HRMS (ESI) calcd for

C22H25CIN3 (M + H) ⁺ 366.1731, found 366.1735.

N-((4'-(4-Chlorophenyl)-[2,2'-bipyrrol]-5'-ylidene)methyl)cy clooctanamine (118)

^X H NMR (CDCb, 400 MHz) δ 7.38 (d, = 7.6 Hz, 2H), 7.35 (s, 1H), 7.27 (d, = 7.6 Hz, 2H), 6.96 (dd, / = 1.3, 2.6 Hz, 1H), 6.67 (dd, = 1.3, 3.7 Hz, 1H), 6.51 (s, 1H), 6.21 (dd, / = 2.6, 3.7 Hz, 1H), 3.54 (m, 1H), 1.89 (m, 4H), 1.76 (m, 2H), 1.54 (m, 8H); ¹³ C NMR (CDCb, 100 MHz) δ 144.5, 142.8, 140.1, 134.9, 131.4, 130.1 (2C), 129.3 (2C), 123.3, 122.7, 119.9, 112.0, 110.6, 109.6, 63.8, 32.6 (2C), 26.9 (2C), 25.3, 23.4 (2C); HRMS (ESI) calcd for C23H27CIN3 (M + H) ⁺ 380.1888, found 380.1906.

N-((4'-(4-Chlorophenyl)-[2,2'-bipyrrol]-5'-ylidene)methyl)ad amantan-l-amine (119)

lH NMR (CDCb, 400 MHz) δ 7.41 (d, = 7.6 Hz, 2H), 7.33 (s, 1H), 7.26 (d, = 7.6 Hz, 2H), 7.01 (d, = 1.2 Hz, 1H), 6.71 (d, = 1.2 Hz, 1H), 6.55 (s, 1H), 6.22 (dd, / = 1.2, 2.7 Hz, 1H), 2.16 (br s, 3H), 1.92 (d, = 2.8 Hz, 6H), 1.65 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 144.3, 141.3, 141.1, 135.2, 131.3, 130.0 (2C), 129.4 (2C), 123.9, 122.5, 119.2, 112.7, 110.6, 110.1, 57.4, 42.2 (3C), 35.5 (3C), 29.2 (3C); HRMS (ESI) calcd for C25H27CIN3 (M + H) ⁺ 404.1888, found 404.1860.

N-((4'-Methyl-[2,2'-bipyrrol]- '-ylidene)methyl)undecan-l-amine (120)

^X H NMR (CDCb, 400 MHz) δ 7.31 (s, 1H), 7.05 (dd, = 2.5, 3.8 Hz, 1H), 6.72 (t, = 1.3 Hz, 1H), 6.39 (s, 1H), 6.27 (m ,1H), 3.52 (t, = 7.2 Hz, 2H), 2.27 (s, 3H), 1.77 (m, 2H), 1.42-1.27 (m, 16H), 0.89 (t, = 7.0 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 143.5, 142.7, 141.8, 123.5, 122.8, 120.8, 112.4, 111.6, 110.2, 51.5, 31.9, 30.3, 29.6 (2C), 29.5, 29.3, 29.2, 26.6, 22.7, 14.1, 11.3; HRMS (ESI) calcd for C2iH ₃₄ N ₃ (M + H) ⁺ 328.2747, found 328.2766. N-((4'-Methyl-[2,2'-bipyrrol]-5'-ylidene)methyl)cycloheptana mine hydrochloride

(121)

lH NMR (CDCb, 400 MHz) δ 13.92 (br s, IH), 10.65 (br s, IH), 10.26 (br s, IH), 7.42 (s, IH), 7.02 (m, IH), 6.72 (m, IH), 6.36 (s, IH), 6.25 (m, IH), 3.65 (m, IH), 2.25 (s, 3H), 2.11-2.05 (m, 2H), 1.93-1.78 (m, 4H), 1.62-1.59 (m, 4H), 1.51-1.47 (m, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 142.3, 142.1, 141.8, 123.8, 122.9, 120.7, 112.8, 1 11.6, 110.8, 63.4, 35.7 (2C), 28.0 (2C), 23.9 (2C), 11.6; HRMS (ESI) calcd for Ci ₇ H ₂₄ N ₃ (M + H) ⁺ 270.1965, found 270.1962.

N-((4'-Methyl-[2,2'-bipyrrol]-5'-ylidene)methyl)cyclooctanam ine hydrochloride (122)

^X H NMR (CDCb, 400 MHz) δ 13.96 (br s, IH), 10.64 (br s, IH), 10.19 (br s, IH), 7.40 (d, / = 15.4 Hz, IH), 7.04 (m, IH), 6.72 (m, IH), 6.37 (s, IH), 6.26 (m, IH), 3.69 (m, IH), 2.27 (s, 3H), 2.04-1.98 (m, 4H), 1.85 (m, 2H), 1.60 (m, 8H); ¹³ C NMR (CDCb, 100 MHz) δ 142.0 (2C), 141.5, 123.6, 122.7, 120.5, 112.5, 111.4, 110.5, 62.4 32.5 (2C), 26.9 (2C), 25.3, 23.4 (2C), 11.4; HRMS (ESI) calcd for Ci ₈ H ₂₆ N (M + H) ⁺ 284.2121, found 284.2119.

N-((4' -methyl- [2,2' -bipyrrol] -5 ' -ylidene)methyl)adamantan- 1-amine hydrochloride

(123)

lH NMR (CDCb, 400 MHz) δ 13.91 (br s, IH), 10.63 (br s, IH), 10.27 (d, = 15.6 Hz, IH), 7.42 (d, / = 15.6 Hz, IH), 7.04 (m, IH), 6.72 (m, IH), 6.37 (s, IH), 6.25 (m, IH), 2.28 (s, 3H), 2.24 (br s, 3H), 2.03 (d, = 2.6 Hz, 6H), 1.73 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 142.0 (2C), 138.5, 123.9, 123.0, 120.9, 112.7, 111.6, 110.8, 57.1, 42.7 (3C), 35.8 (3C), 29.5 (3C), 11.7; HRMS (ESI) calcd for C ₂₀ H ₂₆ N (M + H) ⁺ 308.2121, found 308.2120.

N-((4'-Ethyl-[2,2'-bipyrrol]-5'-ylidene)methyl)cycloheptanam ine (124) ^X H NMR (CDCb, 400 MHz) δ 7.43 (s, 1H), 7.03 (dd, 7 = 1.4, 2.6 Hz, 1H), 6.73 (dd, 7 = 1.4, 3.7 Hz, 1H), 6.41 (s, 1H), 6.25 (dd, 7 = 2.6, 3.7 Hz, 1H), 3.64 (m, 1H), 2.62 (q, 7 = 7.6 Hz, 2H), 2.10-2.07 (m, 2H), 1.91-1.81 (m, 4H), 1.62-1.48 (m, 6H), 1.25 (t, 7 = 7.6 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 149.0, 142.3, 141.6, 123.8, 123.0, 119.9, 112.7, 110.8, 109.9, 63.5, 35.7 (2C), 28.1 (2C), 24.0 (2C), 19.4, 15.3; HRMS (ESI) calcd for Ci ₈ H ₂₆ N3 (M + H) ⁺ 284.2121, found 284.2120.

N-((4'-Ethyl-[2,2'-bipyrrol]- '-ylidene)methyl)cyclooctanamine (125)

lH NMR (CDCb, 400 MHz) δ 7.49 (br s, 1H), 7.03 (dd, 7 = 2.5, 3.8 Hz, 1H), 6.74 (m, 1H), 6.41 (s, 1H), 6.26 (m, 1H), 3.68 (m, 1H), 2.62 (q, 7 = 7.5 Hz, 2H), 2.03-1.97 (m, 4H), 1.85-1.82 (m, 2H), 1.64-1.53 (m, 8H), 1.27 (t, 7 = 7.5 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 149.0, 142.4, 141.6, 123.9, 123.0, 119.9, 112.8, 110.8, 109.4, 62.7, 32.8 (2C), 27.3 (2C), 25.5, 23.6 (2C), 19.4, 15.3; HRMS (ESI) calcd for Ci ₉ H ₂₈ N ₃ (M + H) ⁺ 298.2278, found 298.2276.

N-((4'-Ethyl-[2,2'-bipyrrol]-5'-ylidene)methyl)adamantan-l-a mine hydrochloride (126)

lH NMR (CDCb, 400 MHz) δ 13.92 (br s, 1H), 10.65 (br s, 1H), 10.30 (d, 7 = 15.4 Hz, 1H), 7.44 (d, 7 = 15.4 Hz, 1H), 7.05 (m, 1H), 6.73 (m, 1H), 6.92 (s, 1H), 6.26 (m, 1H), 2.64 (q, 7 = 7.6 Hz, 2H), 2.24 (br s, 3H), 2.03 (d, 7 = 2.7 Hz, 6H), 1.74 (m, 6H), 1.28 (t, 7 = 7.6 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 148.8, 142.1, 138.2, 123.9, 123.0, 120.0, 112.7, 1 10.7, 109.9, 57.1, 42.7 (3C), 35.8 (3C), 29.5 (3C), 19.4, 15.2; HRMS (ESI) calcd for C ₂ iH ₂₈ N (M + H) ⁺ 322.2278, found 322.2277.

N-([2,2' -Bipyrrol] -5 ' - mine (127)

lH NMR (CDCb, 400 MHz) δ 7.33 (s, 1H), 6.93 (m, 2H), 6.67 (dd, 7 = 1.2, 3.6 Hz, 1H), 6.47 (m, 1H), 6.20 (dd, 7 = 2.7, 3.6 Hz, 1H), 3.54 (m, 1H), 2.01-1.97 (m, 2H), 1.85-1.72 (m, 4H), 1.56-1.53 (m, 4H), 1.44 (m, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 144.6, 143.0, 130.3, 123.6, 122.8, 121.8, 112.4, 111.1, 110.5, 63.3, 35.3 (2C), 27.8 (2C), 23.7 (2C); HRMS (ESI) calcd for C16H22N3 (M + H) ⁺ 256.1808, found 256.1801.

N-([2,2'-Bipyrrol]-5'-ylidenemethyl)cyclooctanamine hydrochloride (128)

lH NMR (DMSO-d6, 400 MHz) δ 13.41 (br s, IH), 11.73 (br s, IH), 11.66 (br s, IH), 8.30 (br s, IH), 7.27 (br s, IH), 7.05 (s, IH), 6.96 (br s, IH), 6.79 (br s, IH), 6.23 (s, IH), 3.89 (br s, IH), 1.92-1.74 (m, 6H), 1.55 (m, 8H); ¹³ C NMR (CDCI3, 100 MHz) δ 144.8, 143.4, 130.4, 123.6, 122.9, 121.9, 112.3, 111.1, 110.3, 62.5, 32.3 (2C), 27.0 (2C), 25.3, 23.4 (2C); HRMS (ESI) calcd for 0 ₇ Η ₂₄ Ν ₃ (M + H) ⁺ 270.1965, found 270.1957.

N-([2,2' -Bipyrrol] -5 ' -ylidenemethyl)adamantan- 1-amine hydrochloride (129)

lH NMR (CDC1 ₃ , 400 MHz) δ 14.12 (br s, IH), 10.60 (br s, IH), 10.43 (br s, IH), 7.42 (d, = 15.8 Hz, IH), 6.96 (m, 2H), 6.68 (m, IH), 6.48 (m, IH), 6.20 (m, IH), 2.18 (br s, 3H), 1.97 (d, = 2.7 Hz, 6H), 1.71-1.53 (m, 6H); ¹³ C NMR (CDC1 , 100 MHz) δ 142.5, 141.9, 130.2, 123.5, 122.8, 121.9, 112.3, 110.9, 110.5, 57.2, 42.2 (3C), 35.5 (3C), 29.2 (3C); HRMS (ESI) calcd for Ci ₉ H ₂₄ N (M + H) ⁺ 294.1965, found 294.1961.

N-((3 ' -Methyl-[2,2' -bipyrrol]- ' -ylidene)methyl)cycloheptanamine (130)

lH NMR (CDC1 , 400 MHz) δ 7.29 (s, IH), 7.01 (m, IH), 6.74 (s, IH), 6.67 (m, IH), 6.23 (m, IH), 3.54 (m, IH), 2.18 (s, 3H), 2.02-1.96 (m, 2H), 1.84-1.70 (m, 4H), 1.54 (m, 4H), 1.41 (m, 2H); ¹³ C NMR (CDC1 , 100 MHz) δ 143.9, 140.7, 130.3, 123.3, 123.0, 122.2, 120.2, 112.9, 110.5, 63.1, 35.3 (2C), 27.8 (2C), 23.7 (2C), 13.2; HRMS (ESI) calcd for Ci ₇ H ₂₄ N (M + H) ⁺ 270.1965, found 270.1946.

N-((3'-Methyl-[2,2'-bipyrrol]- '-ylidene)methyl)cyclooctanamine (131)

lH NMR (CDC1 , 400 MHz) δ 7.29 (s, IH), 7.01 (m, IH), 6.73 (s, IH), 6.67 (m, IH), 6.23 (m, IH), 3.58 (m, IH), 2.19 (s, 3H), 1.96-1.87 (m, 4H), 1.77-1.72 (m, 2H), 1.56-1.43 (m, 8H); ¹³ C NMR (CDC1 , 100 MHz) δ 144.0, 140.8, 130.3, 123.3, 123.0, 122.3, 120.2, 1 12.8, 110.5, 62.3, 32.3 (2C), 27.0 (2C), 25.3, 23.4 (2C), 13.3; HRMS (ESI) calcd for Ci ₈ H ₂₆ N3 (M + H) ⁺ 284.2121, found 284.2102.

N-((3'-Methyl-[2,2'-bipyrrol]-5'-ylidene)methyl)adamantan-l- amine hydrochloride

(132)

^X H NMR (CDCb, 400 MHz) δ 13.88 (br s, IH), 10.73 (br s, IH), 10.55 (d, / = 15.4 Hz, IH), 7.42 (d, = 15.4 Hz, IH), 7.10 (m, IH), 6.84 (d, = 1.2 Hz, IH), 6.76 (m, IH), 6.33 (m, IH), 2.29 (s, 3H), 2.24 (s, 3H), 2.04 (d, = 2.5 Hz, 6H), 1.73 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 140.9, 140.4, 130.1, 123.3, 123.0, 122.3, 120.3, 112.8, 110.6, 57.1, 42.3 (3C), 35.6 (3C), 29.2 (3C), 13.2; HRMS (ESI) calcd for C20H26N3 (M + H) ⁺ 308.2121, found 308.2101.

N-((3 ' -Ethyl-[2,2' -bipyrrol] -5 ' -ylidene)methyl)cycloheptanamine hydrochloride

(133)

lH NMR (CDCb, 400 MHz) δ 13.61 (br s, IH), 10.65 (br s, IH), 10.42 (br s, IH), 7.32 (d, = 15.2 Hz, IH), 7.01 (m, IH), 6.79 (s, IH), 6.68 (m, IH), 6.23 (m, IH), 3.57 (br s, IH), 2.60 (q, = 7.5 Hz, 2H), 2.04-1.99 (m, 2H), 1.87-1.71 (m, 4H), 1.55-1.52 (m, 4H), 1.43 (m, 2H), 1.20 (t, = 7.5 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 143.8, 140.0, 129.2, 128.1, 123.3, 122.7, 120.3, 112.9, 110.7, 63.0, 35.3 (2C), 27.8 (2C), 23.7 (2C), 20.2, 13.1 ; HRMS (ESI) calcd for 0 ₈ Η ₂₆ Ν ₃ (M + H) ⁺ 284.2121, found 284.2102.

N-((3'-Ethyl-[2,2'-bipyrrol]- '-ylidene)methyl)cyclooctanamine hydrochloride (134)

^X H NMR (CDCb, 400 MHz) δ 13.87 (br s, IH), 10.68 (br s, IH), 10.40 (br s, IH), 7.31 (d, / = 15.3 Hz, IH), 7.01 (m, IH), 6.79 (s, IH), 6.68 (m, IH), 6.24 (m, IH), 3.61 (br s, IH), 2.60 (q, = 7.3 Hz, 2H), 1.97-1.87 (m, 4H), 1.79-1.72 (m, 2H), 1.60-1.41 (m, 8H), 1.20 (t, = 7.3 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 143.8, 140.0, 129.2, 128.0, 123.3, 122.7, 120.3, 112.9, 110.6, 62.3, 32.3 (2C), 26.7 (2C), 25.3, 23.4 (2C), 20.3, 13.1 ; HRMS (ESI) calcd for 0 ₉ Η ₂₈ Ν ₃ (M + H) ⁺ 298.2278, found 298.2260. N-((3 ' -Ethyl-[2,2' -bipyrrol] -5 ' -ylidene)methyl)adamantan-l-amine hydrochloride

(135)

lH NMR (CDCb, 400 MHz) δ 13.83 (br s, IH), 10.68 (br s, IH), 10.51 (d, J = 15.8 Hz, IH), 7.35 (d, J = 15.8 Hz, IH), 7.02 (d, J = 1.1 Hz, IH), 6.81 (s, IH), 6.68 (dd, = 1.1, 3.5 Hz, IH), 6.23 (m, IH), 2.60 (q, J = 7.4 Hz, 2H), 2.15 (s, 3H), 1.95 (d, J = 2.6 Hz, 6H), 1.66 (m, 6H), 1.21 (t, 7 = 7.4 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 140.9, 139.7, 129.1, 128.0, 123.2, 122.8, 120.5, 112.7, 110.6, 57.0, 42.3 (3C), 35.5 (3C), 29.2 (3C), 20.3, 13.2; HRMS (ESI) calcd for C21H28N3 (M + H) ⁺ 322.2278, found 322.2259.

N-((3 ' -Isopropyl-[2,2' -bipyrrol] -5 ' -ylidene)methyl)cycloheptanamine hydrochloride

(136)

^X H NMR (CDCb, 400 MHz) δ 7.31 (s, IH), 7.01 (d, J = 1.0 Hz, IH), 6.82 (s, IH), 6.70 (s, IH), 6.23 (m, IH), 3.56 (m, IH), 3.11 (m, IH), 2.03-1.96 (m, 2H), 1.84-1.77 (m, 4H), 1.73-1.71 (m, 4H), 1.55-1.41 (m, 2H), 1.19 (d, J = 6.8 Hz, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 144.0, 139.6, 134.6, 126.6, 123.2, 122.4, 120.5, 112.8, 110.6, 63.3, 35.3 (2C), 27.8 (2C), 25.6, 23.7 (2C), 22.9 (2C); HRMS (ESI) calcd for C19H28N3 (M + H) ⁺ 298.2278, found 298.2269.

N-((3 ' -Isopropyl-[2,2' -bipyrr -5 ' -ylidene)methyl)cyclooctanamine (137)

^X H NMR (CDCb, 400 MHz) δ 7.28 (s, IH), 7.02 (m, IH), 6.82 (s, IH), 6.70 (dd, = 2.4, 3.6 Hz, IH), 6.23 (m, IH), 3.60 (m, IH), 3.11 (m, IH), 1.95-1.89 (m, 4H), 1.76 (m, 2H), 1.55-1.50 (m, 8H), 1.20 (d, 7 = 6.7 Hz, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 144.1, 139.8, 134.6, 126.6, 123.2, 122.4, 120.5, 112.8, 110.5, 62.3, 32.3 (2C), 26.9 (2C), 25.6, 25.3, 23.4 (2C), 22.9 (2C); HRMS (ESI) calcd for C20H30N3 (M + H) ⁺ 312.2434, found 312.2425. N-((3 ' -Isopropyl-[2,2' -bipyrrol] -5 ' -ylidene)methyl)adamantan- 1- hydrochloride (138)

lH NMR (CDCb, 400 MHz) δ 7.35 (d, 7 = 15.3 Hz, IH), 7.02 (dd, 7 = 1.3, 2.4 Hz, IH), 6.84 (s, IH), 6.71 (dd, 7 = 2.4, 3.8 Hz, IH), 6.23 (m, IH), 3.11 (m, IH), 2.16 (s, 3H), 1.95 (d, 7 = 2.8 Hz, 6H), 1.66 (m, 6H), 1.19 (d, 7 = 6.8 Hz, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 141.0, 139.3, 134.5, 126.3, 123.1, 122.6, 120.6, 112.6, 110.5, 57.0, 42.3 (3C), 35.6 (3C), 29.2 (3C), 25.7, 22.9 (2C); HRMS (ESI) calcd for C22H30N3 (M + H) ⁺ 336.2434, found 336.2425.

N-((3 ' -(tert-Butyl)- [2,2' -bipyrrol]-5 ' -ylidene)methyl)cycloheptanamine

hydrochloride (139)

^X H NMR (CDCb, 400 MHz) δ 13.51 (br s, IH), 1 1.05 (br s, IH), 10.84 (br s, IH), 7.33 (d, 7 = 15.3 Hz, IH), 7.00 (dd, 7 = 1.8, 2.8 Hz, IH), 6.86 (dd, 7 = 1.8, 3.6 Hz, IH), 6.84 (s, IH), 6.23 (m, IH), 3.57 (m, IH), 2.04-1.97 (m, 2H), 1.88-1.72 (m, 4H), 1.53 (m, 4H), 1.45-1.39 (m, 2H), 1.35 (s, 9H); ¹³ C NMR (CDCb, 100 MHz) δ 144.3, 139.6, 137.1, 127.9, 123.0, 122.6, 119.4, 115.9, 110.3, 63.3, 35.3 (2C), 31.4, 29.9 (3C), 27.8 (2C), 23.7 (2C); HRMS (ESI) calcd for

C20H30N3 (M + H) ⁺ 312.2434, found 312.2431.

N-((3 ' -(tert-Butyl)- [2,2' -bip l)cyclooctanamine (140)

^X H NMR (CDCb, 400 MHz) δ 7.30 (s, IH), 7.00 (d, 7 = 1.0 Hz, IH), 6.85 (s, IH), 6.84 (br s, IH), 6.23 (dd, 7 = 2.8, 3.6 Hz, IH), 3.60 (m, IH), 1.95-1.90 (m, 4H), 1.76 (m, 2H), 1.58-1.46 (m, 8H), 1.37 (s, 9H); ¹³ C NMR (CDCb, 100 MHz) δ 144.2, 139.6, 137.1, 128.0, 122.8, 122.4, 119.3, 115.8, 110.1, 62.4, 32.3 (2C), 31.4, 30.0 (3C), 26.9 (2C), 26.6, 25.3, 23.4: HRMS (ESI) calcd for C21H32N3 (M + H) ⁺ 326.2591, found 326.2584. N-((3 ' -(tert-Butyl)- [2,2' -bipyrrol]-5 ' -ylidene)methyl)adamantan- 1- hydrochloride (141)

lH NMR (CDCb, 400 MHz) δ 13.39 (br s, IH), 1 1.05 (br s, IH), 10.94 (br s, IH), 7.38 (d, = 15.8 Hz, IH), 6.99 (s, IH), 6.90 (s, IH), 6.83 (br s, IH), 6.22 (s, IH), 2.15 (br s, 3H), 1.96 (d, = 2.6 Hz, 6H), 1.66 (m, 6H), 1.35 (s, 9H); ¹³ C NMR (CDCb, 100 MHz) δ 141.6, 139.4, 137.0, 128.0, 122.9, 122.6, 119.6, 115.6, 110.1, 57.2, 42.2 (3C), 35.5 (3C), 31.4, 30.0 (3C), 29.2 (3C): HRMS (ESI) calcd for C23H32N3 (M + H) ⁺ 350.2591, found 350.2578.

N-((3'-Ethyl-4'-methyl-[2,2'-bipyrrol]-5'-ylidene)methyl)but an-l-amine (142)

^X H NMR (CDCb, 400 MHz) δ 7.30 (s, IH), 7.00 (dd, = 0.9, 2.4 Hz, IH), 6.71 (dd, / = 0.9, 3.6 Hz, IH), 6.23 (dd, = 2.4, 3.6 Hz, IH), 3.48 (t, = 7.2 Hz, 2H), 2.55 (q, = 7.5 Hz, 2H), 2.10 (s, 3H), 1.69 (m, 2H), 1.39 (m, 2H), 1.08 (t, = 7.5 Hz, 2H, 3H), 0.89 (t, = 6.2 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 143.1, 140.1, 139.1, 126.9, 123.4, 122.5, 119.9, 1 12.7, 110.7, 51.1, 32.2, 19.8, 18.0, 13.6 (2C), 10.5; HRMS (ESI) calcd for 0 ₆ Η ₂₄ Ν ₃ (M + H) ⁺ 258.1965, found 258.1963.

N-((3 ' -Ethyl-4' -methyl- [2,2' -b methyl)octan- 1-amine (143)

^X H NMR (CDCb, 400 MHz) δ 7.29 (s, IH), 7.00 (m, IH), 6.71 (dd, J = 1.2, 3.2 Hz, IH), 6.23 (dd, = 2.4, 3.2 Hz, IH), 3.47 (t, = 7.2 Hz, 2H), 2.55 (q, = 7.6 Hz, 2H), 2.10 (s, 3H), 1.71 (m, 2H), 1.33 (m, 10H), 1.20 (t, = 7.6 Hz, 3H), 0.87 (t, = 6.0 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 143.1, 140.0, 139.1, 126.9, 123.2, 122.4, 119.9, 1 12.7, 110.7, 51.4, 31.7, 30.2, 29.1 (2C), 26.5, 22.6, 18.0, 14.1, 13.6, 9.1 ; HRMS (ESI) calcd for C20H32N3 (M + H) ⁺ 314.2591, found 314.2591. N-((3 ' -Ethyl-4' -methyl- [2,2' -bipyrrol]-5 ' -ylidene)methyl)cyclopropanamine (144)

lH NMR (CDCb, 400 MHz) δ 7.50 (s, IH), 6.96 (dd, 7 = 1.1, 2.6 Hz, IH), 6.65 (dd, 7 = 1.1, 3.7 Hz, IH), 6.22 (dd, J = 2.6, 3.7 Hz, IH), 2.99 (m, IH), 2.52 (q, 7 = 7.5 Hz, 2H), 2.10 (s, 3H), 1.08 (t, 7 = 7.5 Hz, 3H), 0.93-0.86 (m, 4H); ¹³ C NMR (CDCb, 100 MHz) δ 143.5, 138.8, 137.5, 126.8, 122.9, 122.6, 120.9, 112.3, 110.6, 32.8, 17.9, 13.8, 9.1, 7.1 (2C): HRMS (ESI) calcd for C15H20N3 (M + H) ⁺ 242.1652, found 242.1653.

N-((3 ' -Ethyl-4' -methyl- [2,2' -bipyrrol]-5 ' -ylidene)methyl)cycloheptanamine (145)

lH NMR (CDCb, 400 MHz) δ 7.31 (s, IH), 7.01 (m, IH), 6.70 (m, IH), 6.23 (m, IH), 3.56 (m, IH), 2.52 (q, 7 = 7.5 Hz, 2H), 2.12 (s, 3H), 2.04-1.99 (m, 2H), 1.86-1.73 (m, 4H), 1.54 (m, 4H), 1.42 (m, 2H), 1.08 (t, 7 = 7.5 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 141.1, 139.9, 138.9, 126.8, 123.2, 122.5, 119.8, 112.5, 110.5, 63.2, 35.5 (2C), 27.8 (2C), 23.7 (2C), 18.0, 13.7, 9.2; HRMS (ESI) calcd for C19H28N3 (M + H) ⁺ . 298.22777, found 298.22804; HRMS (ESI) calcd for C19H28N3 (M + H) ⁺ 298.2278, found 298.2279.

N-((3 ' -Ethyl-4' -methyl- [2,2' -bipyrrol]-5 ' -ylidene)methyl)cyclooctanamine (146)

^X H NMR (CDCb, 400 MHz) δ 7.32 (s, IH), 7.00 (d, 7 = 1.0 Hz, IH), 6.70 (m, IH), 6.22 (m, IH), 3.59 (m, IH), 2.58 (q, 7 = 7.5 Hz, 2H), 2.12 (s, 3H), 1.96-1.89 (m, 4H), 1.78-1.73 (m, 2H), 1.58-1.42 (m, 8H), 1.07 (t, 7 = 7.5 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 141.2, 139.9, 138.9, 126.8, 123.2, 122.5, 119.8, 112.5, 110.5, 63.4, 32.5 (2C), 27.0 (2C), 25.3, 23.4 (2C), 18.0, 13.6, 9.2; HRMS (ESI) calcd for C20H30N3 (M + H) ⁺ 312.2434, found 312.2435.

N-((3 ' -Ethyl-4' -methyl- [2,2' -bipyrrol]-5 ' -ylidene)methyl)adamantan- 1-amine hydrochloride (147).

^l H NMR (CDCb, 400 MHz) δ 13.62 (s, IH), 10.92 (br s, IH), 10.41 (d, 7 = 15.6 Hz, IH), 7.43 (d, 7 = 15.6 Hz, IH), 7.10 (m, IH), 6.78 (m, IH), 6.31 (m, IH), 2.66 (q, 7 = 7.6 Hz, 2H), 2.24 (br s, 3H), 2.21 (s, 3H), 2.04 (d, 7 = 2.6 Hz, 6H), 1.74 (m, 6H), 1.16 (t, 7 = 7.6 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 139.5, 138.6, 137.8, 126.7, 123.1, 122.6, 120.0, 112.4, 110.5, 56.7, 42.4 (3C), 35.6 (3C), 29.2 (3C), 18.0, 13.6, 9.3; HRMS (ESI) calcd for C22H30N3 (M + H) ⁺ 336.2434, found 336.2434.

l-Benzyl-N-((3 ' -ethyl-4' -methyl-[2,2' -bipyrrol] -5 ' -ylidene)methyl)piperidin-4-amine hydrochloride (148)

lH NMR (CDCb, 400 MHz) δ 7.37 (m, 3H), 7.27-7.19 (m, 3H), 7.02 (m, IH), 6.74 (d, 7 = 2.3 Hz, IH), 6.25 (m, IH), 3.36 (br s, 3H), 3.14 (br s, 2H), 2.55 (q, 7 = 7.6 Hz, 2H), 2.22-2.19 (m, 4H), 2.12 (s, 3H), 1.91 (m, 2H), 1.08 (t, 7 = 7.6 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 140.9, 140.7, 139.8, 132.3, 129.7, 127.9, 127.4, 123.6, 122.8, 122.3, 120.3, 119.3, 113.2, 110.9, 110.8, 62.2, 56.9 (2C), 50.2, 31.3 (2C), 18.0, 13.6, 9.3; HRMS (ESI) calcd for C ₂ 4H ₃ iN ₄ (M + H) ⁺ 375.2543, found 375.2538.

N-((3 ' -Ethyl-4' -methyl- [2,2' - )methyl)morpholin-4-amine (149)

^X H NMR (CDCb, 400 MHz) δ 7.60 (s, IH), 6.68 (br s, IH), 6.23 (br s, IH), 6.19 (br s, IH), 3.80 (m, 4H), 3.00 (t, 7 = 4.4 Hz, 4H), 2.46 (q, 7 = 7.5 Hz, 2H), 2.07 (s, 3H), 1.07 (t, 7 = 7.5 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 131.3, 125.0, 124.2, 124.0, 122.7, 122.0, 117.8, 109.5, 106.6, 66.4 (2C), 52.9 (2C), 17.9, 15.4, 8.7; HRMS (ESI) calcd for C16H23N4O (M + H) ⁺ 287.1866, found 287.1872.

N-((4' -Ethyl-3 ' -methyl- [2,2' -bipyrrol]-5 ' -ylidene)methyl)cycloheptanamine (150)

lH NMR (CDCb, 400 MHz) δ 7.30 (s, IH), 7.01 (m, IH), 6.70 (m, IH), 6.23 (m, IH), 3.56 (m, IH), 2.52 (q, 7 = 7.4 Hz, 2H), 2.11 (s, 3H), 2.04-1.99 (m, 2H), 1.84-1.73 (m, 4H), 1.55 (m, 4H), 1.43 (m, 2H), 1.08 (t, 7 = 7.4 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 145.8, 140.9, 140.6, 123.3, 123.0, 119.5, 118.8, 112.9, 110.4, 63.1, 35.5 (2C), 27.8 (2C), 23.7 (2C), 17.6, 16.4, 10.5; HRMS (ESI) calcd for C19H28N3 (M + H) ⁺ 298.2278, found 298.2280.

N-((4' -Ethyl-3 ' -methyl- [2,2' -bipyrrol]-5 ' -ylidene)methyl)cyclooctanamine (151)

lH NMR (CDCI3, 400 MHz) δ 7.30 (s, IH), 7.01 (m, IH), 6.70 (m, IH), 6.22 (m, IH), 3.59 (m, IH), 2.52 (q, = 7.6 Hz, 2H), 2.11 (s, 3H), 1.95-1.89 (m, 4H), 1.77-1.75 (m, 2H), 1.56-1.44 (m, 8H), 1.09 (t, = 7.4 Hz, 3H); ¹³ C NMR (CDCI3, 100 MHz) δ 145.8, 140.9, 140.7, 123.3, 123.0, 119.5, 118.8, 112.9, 110.4, 62.3, 32.5 (2C), 27.0 (2C), 25.3, 23.4 (2C), 17.6, 16.4, 10.5; HRMS (ESI) calcd for C20H30N3 (M + H) ⁺ 312.2434, found 312.2437.

N-((4'-Ethyl-3'-methyl-[2,2'-bipyrrol]-5'-ylidene)methyl)ada mantan-l-amine (152)

^X H NMR (CDCI3, 400 MHz) δ 7.33 (d, = 15.4 Hz, IH), 7.03 (m, IH), 6.70 (m, IH), 6.24 (m, IH), 2.54 (q, = 7.6 Hz, 2H), 2.16 (br s, 3H), 2.12 (s, 3H), 1.96 (d, = 2.6 Hz, 6H), 1.66 (m, 6H), 1.10 (t, 7 = 7.6 Hz, 3H); ¹³ C NMR (CDCI3, 100 MHz) δ 145.3, 140.3, 137.5, 123.3, 123.0, 119.4, 118.0, 112.8, 110.4, 56.7, 42.4 (3C), 35.6 (3C), 29.2 (3C), 17.7, 16.4, 10.5; HRMS (ESI) calcd for C22H30N3 (M + H) ⁺ 336.2434, found 336.2434.

N-((3 ' ,4' -Dimethyl- [2,2' -bipyrrol] -5 ' -ylidene)methyl)cycloheptanamine

hydrochloride (153)

^X H NMR (CDCI3, 400 MHz) δ 13.46 (br s, IH), 10.75 (br s, IH), 10.10 (br s, IH), 7.23 (d, / = 15.2 Hz, IH), 7.02 (m, IH), 6.70 (m, IH), 6.23 (dd, / = 1.2, 2.2 Hz, IH), 3.56 (m, IH), 2.10 (s, 3H), 2.09 (s, 3H), 2.01 (m, 2H), 1.86-1.82 (m, 4H), 1.56-1.54 (m, 6H); ¹³ C NMR (CDCI3, 100 MHz) δ 140.9, 140.4, 139.3, 123.4, 122.9, 120.3, 119.7, 1 13.0, 110.5, 63.1, 35.5 (2C), 27.8 (2C), 23.7 (2C), 10.6, 9.5; HRMS (ESI) calcd for Ci ₈ H ₂₆ N3 (M + H) ⁺ 284.2121, found 284.2126. N-((3 ' ,4' -Dimethyl- [2,2' -bipyrrol] -5 ' -ylidene)methyl)cyclooctanamine hydrochloride

(154)

lH NMR (CDCb, 400 MHz) δ 13.54 (br s, 1H), 10.77 (br s, 1H), 10.10 (br s, 1H), 7.30 (d, = 15.3 Hz, 1H), 7.02 (m, 1H), 6.70 (dd, / = 1.2, 2.6 Hz, 1H), 6.23 (dd, = 2.6, 3.8 Hz, 1H), 3.60 (m, 1H), 2.11 (s, 3H), 2.10 (s, 3H), 1.96-1.91 (m, 4H), 1.77 (m, 2H), 1.57-1.52 (m, 8H); ¹³ C NMR (CDCb, 100 MHz) δ 141.0, 140.4, 139.2, 123.4, 122.9, 120.3, 119.8, 1 13.0, 110.5, 62.5, 32.6 (2C), 27.0 (2C), 25.3, 23.4 (2C), 10.6, 9.5; HRMS (ESI) calcd for C19H28N3 (M + H) ⁺ 298.2278, found 298.2286.

N-((3',4'-Dimethyl-[2,2'-bipyrrol]-5'-ylidene)methyl)adamant an-l-amine

hydrochloride (155)

^X H NMR (CDCb, 400 MHz) δ 13.56 (br s, 1H), 10.79 (br s, 1H), 10.23 (d, = 15.2 Hz, 1H), 7.33 (d, / = 15.2 Hz, 1H), 7.03 (m, 1H), 6.70 (m, 1H), 6.23 (m, 1H), 2.16 (br s, 3H), 2.11 (s, 3H), 2.09 (s, 3H), 1.96 (d, = 2.8 Hz, 6H), 1.67 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 140.2, 139.0, 137.7, 123.3, 123.0, 120.2, 119.9, 112.8, 110.4, 56.7, 42.4 (3C), 35.6 (3C), 29.2 (3C), 10.6, 9.6; HRMS (ESI) calcd for C21H28N3 (M + H) ⁺ 322.2278, found 322.2283.

N-((3 ' ,4' -Diethyl- [2,2' -bipyrr -5 ' -ylidene)methyl)cycloheptanamine (156)

lH NMR (CDCb, 400 MHz) δ 7.45 (br s, 1H), 7.00 (m, 1H), 6.70 (m, 1H), 6.23 (m, 1H), 3.57 (m, 1H), 2.61-2.49 (two q, = 7.5 Hz, 4H), 2.04-1.99 (m, 2H), 1.85-1.73 (m, 4H), 1.55-1.52 (m, 4H), 1.42 (m, 2H), 1.14-1.09 (two t, = 7.5 Hz, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 145.4, 141.0, 140.0, 126.2, 123.2, 122.5, 118.8, 112.5, 110.5, 63.1, 35.5 (2C), 27.8 (2C), 23.7 (2C), 17.8, 17.5, 17.3, 14.2; HRMS (ESI) calcd for C20H30N3 (M + H) ⁺ 312.2434, found 312.2415.

N-((3 ' ,4' -Diethyl- [2,2' -bipyrr -5 ' -ylidene)methyl)cyclooctanamine (157) ^l H NMR (CDCb, 400 MHz) δ 7.49 (s, IH), 7.07 (m, IH), 6.77 (m, IH), 6.30 (m, IH), 3.67 (m, IH), 2.68-2.57 (two q, J = 7.6 Hz, 4H), 2.02-1.96 (m, 4H), 1.83 (m, 2H), 1.61-1.52 (m, 8H), 1.25-1.16 (two t, J = 7.6 Hz, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 145.4, 141.0, 140.0, 126.1, 123.1, 122.5, 118.8, 112.5, 110.5, 63.4, 35.5 (2C), 27.0 (2C), 25.3, 23.4 (2C), 17.8, 17.5, 17.3, 14.2; HRMS (ESI) calcd for C21H32N3 (M + H) ⁺ 326.2591, found 326.2570.

N-((3 ' ,4' -Diethyl- [2,2' -bipyrrol] -5 ' -ylidene)methyl)adamantan- 1-amine

hydrochloride (158)

lH NMR (CDCb, 400 MHz) δ 13.61 (br s, IH), 10.93 (br s, IH), 10.42 (d, J = 15.5 Hz, IH), 7.41 (d, J = 15.5 Hz, IH), 7.10 (m, IH), 6.78 (m, IH), 6.31 (m, IH), 2.69-2.58 (two q, 7 = 7.5

Hz, 4H), 2.24 (br s, 3H), 2.04 (d, = 2.8 Hz, 6H), 1.74 (m, 6H), 1.26 (two t, = 7.5 Hz, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 145.2, 139.7, 137.7, 126.1, 123.1, 122.6, 119.0, 1 12.4, 110.5, 56.7, 42.4 (3C), 35.6 (3C), 29.2 (3C), 17.8, 17.5, 17.3, 14.2; HRMS (ESI) calcd for C23H32N3 (M + H) ⁺ 350.2591, found 350.2568.

N-((3-(Pyrrol-2-yl)-4,5,6,7-tetrahydro-isoindol-l-ylidene)me thyl)cycloheptanamine

(159)

^X H NMR (CDCb, 400 MHz) δ 7.21 (s, IH), 7.01 (m, IH), 6.62 (m, IH), 6.21 (m, IH), 3.51 (m, IH), 2.53 (two t, J = 5.9, 6.0 Hz, 4H), 2.05-1.96 (m, 2H), 1.82-1.69 (m, 8H), 1.53 (m, 4H), 1.42 (m, 2H); ¹³ C NMR (CDCb, 100 MHz) δ 141.8, 140.3, 139.7, 123.5, 122.9, 122.5, 118.7, 1 13.1, 110.5, 62.8, 35.5 (2C), 27.8 (2C), 23.7 (2C), 22.7, 22.5, 22.0, 21.4; HRMS (ESI) calcd for C20H28N3 (M + H) ⁺ 310.2278, found 310.2280.

N-((3-(Pyrrol-2-yl)-4,5,6,7-tetrahydro-isoindol-l-ylidene)me thyl)cyclooctanamine

(160)

lH NMR (CDCb, 400 MHz) δ 7.21 (s, IH), 7.01 (m, IH), 6.62 (m, IH), 6.21 (m, IH), 3.56 (m, IH), 2.54 (two t, / = 5.8, 5.9 Hz, 4H), 1.96-1.86 (m, 4H), 1.79-1.69 (m, 6H), 1.59-1.41 (m, 8H); ¹³ C NMR (CDCb, 100 MHz) δ 141.7, 140.4, 139.8, 123.5, 122.9, 122.5, 118.7, 113.0, 110.5, 62.1, 32.5 (2C), 27.0 (2C), 25.3, 23.4 (2C), 22.8, 22.5, 22.0, 21.4; HRMS (ESI) calcd for C21H30N3 (M + H) ⁺ 324.2434, found 324.2436.

N-((3-(Pyrrol-2-yl)-4,5,6,7-tetrahydro-isoindol-l-ylidene)me thyl)adamantan-l- amine (161)

^X H NMR (CDCb, 400 MHz) δ 7.29 (d, = 15.5 Hz, IH), 7.02 (m, IH), 6.63 (m, IH), 6.22 (m, IH), 2.56 (two t, J = 5.9, 6.0 Hz, 4H), 2.15 (br s, 3H), 1.93 (d, = 2.8 Hz, 6H), 1.79-1.54 (m, 10H); ¹³ C NMR (CDCb, 100 MHz) δ 141.5, 139.4, 137.0, 123.4, 123.0, 122.4, 118.8, 112.9, 110.5, 56.4, 42.5 (3C), 35.6 (3C), 29.2 (3C), 22.8, 22.5, 22.0, 21.5; HRMS (ESI) calcd for C23H30N3 (M + H) ⁺ 348.2434, found 348.2434.

N-((3'-Chloro-4'-ethyl-[2,2'-bipyrrol]-5'-ylidene)methyl)-2- methylpropan-l-amine

(162)

lH NMR (CDCb, 400 MHz) δ 7.40 (s, IH), 7.30 (dd, / = 1.3, 3.8 Hz, IH), 7.09 (dd, / = 1.3, 2.6 Hz, IH), 6.33 (dd, = 2.6, 3.8 Hz, IH), 3.40 (d, = 6.9 Hz, 2H), 2.46 (q, = 7.6 Hz, 2H), 2.09- 2.06 (m, IH), 1,21 (t, = 7.6 Hz, 3H), 1.04 (d, = 6.7 Hz, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 144.8, 144.1, 137.7, 123.9, 121.1, 117.7, 114.5, 112.8, 110.8, 59.4, 29.4, 19.8 (2C), 17.7, 15.3; HRMS (ESI) calcd for C15H21CIN3 (M + H) ⁺ 278.1419, found 278.1432.

N-((3 ' -Chloro-4' -ethyl-[2,2' -bipyrrol] -5 ' -ylidene)methyl)cycloheptanamine (163)

^X H NMR (CDCb, 400 MHz) δ 7.45 (s, IH), 7.29 (m, IH), 7.10 (m, IH), 6.33 (m, IH), 3.67 (m, IH), 2.66 (q, = 7.6 Hz, 2H), 2.09-2.05 (m, 2H), 1.95-1.81 (m, 4H), 1.64 (m, 4H), 1.52 (m, 2H), 1.22 (t, = 7.6 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 143.8, 142.4, 137.6, 123.8, 121.1, 117.6, 114.3, 112.7, 110.6, 63.8, 35.3 (2C), 27.8 (2C), 23.8 (2C), 17.7, 14.3; HRMS (ESI) calcd for C18H25CIN3 (M + H) ⁺ 318.1731, found 318.1740. N-((3'-Chloro-4'-ethyl-[2,2'-bipyrrol]-5'-ylidene)methyl)cyc looctanamine (164)

lH NMR (CDCb, 400 MHz) δ 7.48 (s, 1H), 7.28 (dd, 7 = 1.3, 3.8 Hz, 1H), 7.10 (dd, 7 = 1.3, 2.6 Hz, 1H), 6.34 (dd, J = 2.6, 3.8 Hz, 1H), 3.73 (m, 1H), 2.67 (q, 7 = 7.6 Hz, 2H), 2.05-2.00 (m, 4H), 1.89-1.84 (m, 2H), 1.68-1.59 (m, 8H), 1.23 (t, 7 = 7.6 Hz, 3H); ¹³ C NMR (CDCb, 100

MHz) δ 143.6, 142.4, 137.3, 123.8, 121.1, 117.7, 114.2, 1 12.6, 110.7, 63.2, 32.4 (2C), 26.9 (2C), 25.3, 23.4 (2C), 17.7, 15.3; HRMS (ESI) calcd for C19H27CIN3 (M + H) ⁺ 332.1888, found 332.1896.

N-((3'-Chloro-4'-ethyl-[2,2'-bipyrrol]-5'-ylidene)methyl)ada mantan-l-amine (165)

^X H NMR (CDCb, 400 MHz) δ 7.47 (s, 1H), 7.29 (m, 1H), 7.11 (br s, 1H), 6.33 (m, 1H), 2.68 (q, 7 = 7.5 Hz, 2H), 2.26 (br s, 3H), 2.04 (d, 7 = 2.7 Hz, 6H), 1.76 (m, 6H), 1.23 (t, 7 = 7.5 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 143.6, 139.1, 137.3, 123.8, 121.1, 117.8, 114.2, 1 12.6, 110.6, 57.4, 42.2 (3C), 35.5 (3C), 29.2 (3C), 17.8, 15.3; HRMS (ESI) calcd for C21H27CIN3 (M + H) ⁺ 356.1888, found 356.1887.

N-([2,3 ' -Bipyrrol] -5 ' - - 1-amine (166)

^X H NMR (CDCb, 400 MHz) δ 7.62 (s, 1H), 7.53 (m, 1H), 7.00 (s, 1H), 6.75 (dd, 7 = 1.5, 2.7 Hz, 1H), 6.24 (dd, 7 = 1.5, 3.5 Hz, 1H), 6.19 (dd, 7 = 2.7, 3.5 Hz, 1H), 2.18 (br s, 3H), 1.92 (d, 7 = 2.6 Hz, 6H), 1.69 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 146.2, 132.8, 132.0, 131.8, 125.6, 122.1, 118.0, 109.2, 104.9, 58.3, 41.9 (3C), 35.7 (3C), 29.2 (3C); HRMS (ESI) calcd for

Ci ₉ H ₂₄ N3 (M + H) ⁺ 294.1965, found 294.1976.

N-((4'-Methyl-[2,3'-bipyrrol]- '-ylidene)methyl)adamantan-l-amine (167)

lH NMR (CDCb, 400 MHz) δ 7.68 (s, 1H), 7.65 (s, 1H), 6.78 (dd, 7 = 1.5, 2.6 Hz, 1H), 6.16 (m, 2H), 2.31 (s, 3H), 2.15 (br s, 3H), 1.93 (d, 7 = 2.8 Hz, 6H), 1.64 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 143.2, 133.1, 130.4, 124.6, 122.1, 121.5, 118.2, 108.9, 106.5, 58.2, 41.9 (3C), 35.6 (3C), 29.2 (3C), 11.1; HRMS (ESI) calcd for C ₂₀ H ₂₆ N (M + H) ⁺ 308.2121, found 308.2120.

N-((4'-Ethyl-[2,3'-bipyrrol]- '-ylidene)methyl)adamantan-l-amine (168)

lH NMR (CDC1 , 400 MHz) δ 7.66 (s, 1H), 7.64 (s, 1H), 6.79 (dd, / = 1.5, 2.0 Hz, 1H), 6.16 (m, 2H), 2.73 (q, = 7.6 Hz, 2H), 2.16 (br s, 3H), 1.93 (d, = 2.8 Hz, 6H), 1.66 (m, 6H), 1.14 (t, = 7.6 Hz, 3H); ¹³ C NMR (CDC1 , 100 MHz) δ 143.0, 139.6, 130.7, 124.2, 121.5, 120.6, 118.1, 109.0, 106.4, 58.1, 41.9 (3C), 35.6 (3C), 29.2 (3C), 18.2, 16.6; HRMS (ESI) calcd for C ₂ iH ₂₈ N (M + H) ⁺ 322.2278, found 322.2295.

N-((2',4'-Dimethyl-[2,3'-bipyrrol]-5'-ylidene)methyl)adamant an-l-amine

hydrochloride (169)

^X H NMR (DMSO-iM, 400 MHz) δ 13.40 (br s, 1H), 11.74 (br s, 1H), 10.79 (s, 1H), 8.11 (s, 1H), 6.83 (dd, = 2.7, 4.0 Hz, 1H), 6.69 (dd, = 2.7, 5.6 Hz, 1H), 6.04 (dd, = 4.0, 5.6 Hz, 1H), 2.37 (s, 3H), 2.31 (s, 3H), 2.16 (m, 3H), 2.00 (d, = 2.6 Hz, 6H), 1.67 (m, 6H); ¹³ C NMR (DMSO-iM, 100 MHz) δ 144.3, 143.3, 137.4, 122.7, 119.8, 119.5, 118.2, 108.1, 107.8, 57.0, 40.9 (3C), 35.1 (3C), 28.6 (3C), 12.8, 10.3; HRMS (ESI) calcd for C ₂ iH ₂₈ N (M + H) ⁺ 322.2278, found 322.2275.

N-((3,4-Dimethyl-[2,3'-bipyrrol]-5-ylidene)methyl)adamantan- l-amine

hydrochloride (170)

^! H NMR (DMSO-iM, 400 MHz) δ 12.98 (s, 1H), 11.56 (d, = 15.5 Hz, 1H), 11.47 (s, 1H), 7.89 (d, = 15.5 Hz, 1H), 7.55 (t, = 1.0 Hz, 1H), 6.92 (m, 2H), 2.24 (s, 3H), 2.15 (m, 3H), 2.12 (s, 3H), 2.00 (d, = 2.6 Hz, 6H), 1.65 (m, 6H); ¹³ C NMR (DMSO-iM, 100 MHz) δ 142.7, 140.9, 139.8, 119.6, 119.5, 119.2, 118.7, 113.7, 107.1, 56.1, 41.2 (3C), 35.1 (3C), 28.7 (3C), 10.3, 9.3; HRMS (ESI) calcd for C ₂ iH ₂₈ N (M + H) ⁺ 322.2278, found 322.2281. N-((5-(Furan-2-yl)-3,4-dimethyl-pyrrol-2-ylidene)methyl)adam antan-l- hydrochloride (171)

lH NMR (CDCb, 400 MHz) δ 13.34 (s, 1H), 12.27 (d, 7 = 15.5 Hz, 1H), 7.56 (d, 7 = 15.5 Hz, 1H), 7.53 (s, 1H), 7.37 (d, 7 = 3.5 Hz, 1H), 6.52 (dd, 7 = 1.7, 3.5 Hz, 1H), 2.23 (s, 3H), 2.20 (s, 3H), 2.07 (s, 3H), 2.06 (d, 7 = 2.8 Hz, 6H), 1.72 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 146.5, 144.4, 140.8, 139.1, 136.1, 120.9, 120.6, 112.7, 112.6, 57.9, 42.2 (3C), 35.8 (3C), 29.4 (3C), 10.2, 9.9; HRMS (ESI) calcd for C21H27N2O (M + H) ⁺ 323.2118, found 323.2121.

N-((3,4-Dimethyl-5-(thiophen-2-yl)-pyrrol-2-ylidene)methyl)a damantan-l-amine hydrochloride (172)

^! H NMR (CDCb, 400 MHz) δ 13.40 (s, 1H), 12.37 (d, 7 = 15.4 Hz, 1H), 8.16 (dd, 7 = 1.1, 3.8 Hz, 1H), 7.55 (d, 7 = 15.4 Hz, 1H), 7.44 (dd, 7 = 1.1, 5.1 Hz, 1H), 7.18 (dd, 7 = 3.8, 5.1 Hz, 1H), 2.22 (s, 9H), 2.07 (d, 7 = 2.7 Hz, 6H), 1.72 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 140.7, 140.4, 139.2, 132.2, 129.3, 128.7, 128.2, 120.8, 120.7, 58.0, 42.2 (3C), 35.8 (3C), 29.5 (3C), 10.9, 10.1; HRMS (ESI) calcd for C21H27N2S (M + H) ⁺ 339.1889, found 339.1892.

N-((3,4-Dimethyl-5-phenyl-pyrrol-2-ylidene)methyl)adamantan- l-amine

hydrochloride (173)

^! H NMR (CDCb, 400 MHz) δ 13.31 (s, 1H), 12.62 (d, 7 = 15.5 Hz, 1H), 7.85 (d, 7 = 7.3 Hz, 2H), 7.61 (d, 7 = 15.5 Hz, 1H), 7.49 (d, 7 = 7.3 Hz, 2H), 7.39 (m, 1H), 2.25 (s, 6H), 2.18 (br s, 3H), 2.09 (d, 7 = 2.8 Hz, 6H), 1.73 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 146.1, 141.4, 139.4, 130.5, 129.6, 129.2 (2C), 128.4 (2C), 121.0, 120.8, 58.0, 42.2 (3C), 35.8 (3C), 29.5 (3C), 10.9, 10.3; HRMS (ESI) calcd for C23H29N2 (M + H) ⁺ 333.2325, found 333.2326. N-((5-(Indol-2-yl)-3,4-dimethyl-pyrrol-2-ylidene)methyl)adam antan-l-amine (174)

lH NMR (CDCb, 400 MHz) δ 7.63-7.53 (m, 2H), 7.50 (s, IH), 7.26 (m, IH), 7.10 (m, IH), 7.03 (s, IH), 2.29 (s, 3H), 2.27 (br s, 3H), 2.21 (m, 3H), 2.06 (d, = 2.7 Hz, 6H), 1.75 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 139.9, 139.2, 138.9, 137.7, 128.5 (2C), 124.6, 122.0, 121.3, 120.9, 120.7, 112.6, 106.1, 57.7, 42.6 (3C), 35.9 (3C), 29.5 (3C), 11.1, 9.9; HRMS (ESI) calcd for C25H30N3 (M + H) ⁺ 372.2434, found 372.2433.

N-((3-(Imidazol-2-yl)-4,5,6,7-tetrahydro-isoindol-l-ylidene) methyl)adamantan-l- amine hydrochloride (175)

^X H NMR (CDCb, 400 MHz) δ 14.17 (s, IH), 11.66 (br s, IH), 10.49 (d, = 15.6 Hz, IH), 7.52 (d, = 15.6 Hz, IH), 7.25 (s, 2H), 2.93 (br s, 2H), 2.69 (br s, 2H), 2.25 (s, 3H), 2.03 (d, = 2.7 Hz, 6H), 1.82-1.69 (m, 10H); ¹³ C NMR (CDCb, 100 MHz) δ 141.5, 140.2, 139.1, 135.2, 131.2, 125.2, 119.5, 118.7, 57.6, 42.3 (3C), 35.5 (3C), 29.2 (3C), 22.6 (2C), 22.1, 21.5; HRMS (ESI) calcd for C ₂ 2H ₂₉ N ₄ (M + H) ⁺ 349.2387, found 349.2384.

N-((l,3',4'-Trimethyl-[2,2'-bipyrrol]-5'-ylidene)methyl)adam antan-l-amine (176)

^X H NMR (CDCb, 400 MHz) δ 7.59 (br s, IH), 6.75 (dd, / = 1.2, 3.8 Hz, IH), 6.37 (dd, = 2.8, 3.8 Hz, IH), 6.17 (dd, / = 1.2, 2.8 Hz, IH), 3.91 (br s, 3H), 2.22 (s, 6H), 2.04 (m, 9H), 1.72 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 140.1, 138.8 (2C), 126.6, 122.9, 121.8, 120.5, 114.0, 108.4, 57.3, 42.1 (3C), 36.1, 35.6 (3C), 29.2 (3C), 10.1, 9.9; HRMS (ESI) calcd for C22H30N3 (M + H) ⁺ 336.2434, found 336.2435. N-((5-Ethyl-3',4'-dimethyl-[2,2'-bipyrrol]-5'-ylidene)methyl )adamantan-l- hydrochloride (177)

lH NMR (CDCb, 400 MHz) δ 13.56 (s, 1H), 10.82 (s, 1H), 10.12 (d, / = 15.5 Hz, 1H), 7.34 (d, = 15.5 Hz, 1H), 6.69 (dd, = 3.0, 3.4 Hz, 1H), 6.04 (dd, = 3.0, 3.4 Hz, 1H), 2.78 (q, = 7.5 Hz, 2H), 2.23 (m, 3H), 2.18 (s, 3H), 2.16 (s, 3H), 2.03 (d, = 2.9 Hz, 6H), 1.72 (m, 6H), 1.32 (t, = 7.5 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 141.3, 140.9, 139.0, 136.8, 121.9, 120.2 (2C), 114.0, 107.9, 56.6, 42.8 (3C), 35.9 (3C), 29.6 (3C), 21.5, 13.7, 10.9, 9.8; HRMS (ESI) calcd for C23H32N3 (M + H) ⁺ 350.2591, found 350.2606.

N-((5-Isobutyl-3 ' ,4' -dimethyl- [2,2' -bipyrrol] -5 ' -ylidene)methyl)adamantan- 1-amine hydrochloride (178)

^X H NMR (CDCb, 400 MHz) δ 13.51 (s, 1H), 10.79 (s, 1H), 10.07 (d, / = 15.6 Hz, 1H), 7.30 (d, = 15.6 Hz, 1H), 6.64 (dd, = 2.9, 5.8 Hz, 1H), 5.97 (dd, = 2.6, 5.8 Hz, 1H), 2.55 (d, = 7.2 Hz, 2H), 2.54 (m, 3H), 2.12 (s, 3H), 2.10 (s, 3H), 2.04 (m, 1H), 1.98 (d, = 2.8 Hz, 6H), 1.67 (m, 6H), 0.92 (d, = 6.5 Hz, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 140.4, 138.8, 138.6, 136.5, 121.6, 119.9, 119.8, 113.6, 109.1, 56.3, 42.4 (3C), 37.2, 35.6 (3C), 29.2 (3C), 28.8, 22.4 (2C), 10.5, 9.5; HRMS (ESI) calcd for C25H36N3 (M + H) ⁺ 378.2904, found 378.2900.

N-((4-Ethyl-3',4'-dimethyl-[2,2'-bipyrrol]-5'-ylidene)methyl )adamantan-l-amine hydrochloride (179)

^! H NMR (CDCb, 400 MHz) δ 13.50 (s, 1H), 10.51 (br s, 1H), 10.18 (d, = 15.6 Hz, 1H), 7.30 (d, = 15.6 Hz, 1H), 6.81 (dd, 7 = 1.0, 2.5 Hz, 1H), 6.54 (dd, = 1.5, 2.5 Hz, 1H), 2.47 (q, = 7.6 Hz, 2H), 2.15 (s, 3H), 2.16 (s, 3H), 2.09 (s, 3H), 1.95 (d, = 2.7 Hz, 6H), 1.65 (m, 6H), 1.16 (t, = 7.6 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 140.4, 138.9, 137.2, 128.3, 122.6, 120.6, 120.0, 119.9, 112.6, 56.5, 42.4 (3C), 35.6 (3C), 29.3 (3C), 20.0, 15.2, 10.6, 9.6; HRMS (ESI) calcd for C23H32N3 (M + H) ⁺ 350.2591, found 350.2588. N-((3,3 ' ,4' ,5-Tetramethyl- [2,2' -bipyrrol] -5 ' -ylidene)methyl)adamantan- 1-

lH NMR (CDCb, 400 MHz) δ 7.41 (s, 1H), 5.77 (d, = 2.1 Hz, 1H), 2.30 (s, 3H), 2.22 (br s, 3H), 2.20 (s, 3H), 2.15 (s, 6H), 2.03 (d, = 2.7 Hz, 6H), 1.72 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 141.2, 139.4, 137.9, 133.1, 122.9, 120.4, 120.2, 117.8, 111.2, 56.7, 42.3 (3C), 35.6 (3C), 29.2 (3C), 13.8, 13.1, 11.3, 9.9; HRMS (ESI) calcd for C23H32N3 (M + H) ⁺ 350.2591, found 350.2587.

N-((4-Ethyl-3,3 ' ,4' ,5-tetramethyl- [2,2' -bipyrrol]-5 ' -ylidene)methyl)adamantan- 1- amine (181)

^X H NMR (CDCb, 400 MHz) δ 7.39 (s, 1H), 2.39 (q, = 7.5 Hz, 2H), 2.27 (s, 3H), 2.22 (br s, 3H), 2.16 (s, 3H), 2.13 (s, 3H), 2.09 (s, 3H), 2.03 (d, = 2.8 Hz, 6H), 1.73 (m, 6H), 1.06 (t, 7.5 Hz, 3H); ¹³ C NMR (CDCb, 100 MHz) δ 141.5, 139.4, 137.5, 129.6, 123.4, 121.3, 120.4, 120.2, 116.8, 56.6, 42.3 (3C), 35.6 (3C), 29.2 (3C), 17.5, 15.3, 11.7, 11.4 (2C), 9.9; HRMS (ESI) calcd for C25H36N3 (M + H) ⁺ 378.2904, found 378.2901.

N-((2H-Pyrrol-2-ylidene)methy -amine hydrochloride (182)

^X H NMR (CDCb, 600 MHz) δ 13.54 (br s, 1H), 13.04 (br s, 1H), 7.82 (d, = 16.2 Hz, 1H), 7.40 (s, 1H), 7.12 (m, 1H), 6.38 (m, 1H), 2.21 (s, 3H), 2.05 (d, = 2.5 Hz, 6H), 1.68 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 146.8, 134.0, 128.7, 122.9, 113.5, 58.7, 41.6 (3C), 35.2 (3C), 29.1 (3C); HRMS (ESI) calcd for C15H21N2 (M + H) ⁺ 229.1699, found 229.1696.

N-((5-Methyl-pyrrol-2-ylidene)methyl)adamantan-l-amine (183)

lH NMR (CDCb, 600 MHz) δ 7.52 (s, 1H), 6.93 (d, = 3.9 Hz, 1H), 6.09 (d, = 3.9 Hz, 1H), 2.39 (s, 3H), 2.16 (br s, 3H), 1.98 (d, = 2.8 Hz, 6H), 1.65 (m, 6H); ¹³ C NMR (CDCb, 100 MHz) δ 147.5, 144.5, 130.0, 121.9, 113.6, 57.9, 41.8 (3C), 35.5 (3C), 29.1 (3C), 13.9; HRMS (ESI) calcd for Ci ₆ H ₂₃ N2 (M + H) ⁺ 243.1856, found 243.1850.

N-((3,5-Dimethyl-pyrrol-2-ylidene)methyl)adamantan-l-amine hydrochloride (184)

HCI

lH NMR (CDCI3, 400 MHz) δ 13.25 (br s, 1H), 12.04 (d, = 15.9 Hz, 1H), 7.48 (d, = 15.8 Hz, 1H), 5.96 (d, = 1.5 Hz, 1H), 2.37 (s, 3H), 2.24 (s, 3H), 2.21 (br s, 3H), 2.02 (d, = 2.6 Hz, 6H), 1.71 (m, 6H); ¹³ C NMR (CDCI3, 100 MHz) δ 147.1, 141.3, 140.8, 120.2, 114.5, 57.5, 41.9 (3C), 35.5 (3C), 29.1 (3C), 13.8, 11.4; HRMS (ESI) calcd for Ci ₇ H ₂₄ N ₂ (M+H) ⁺ . 257.20123, found 257.20206; HRMS (ESI) calcd for 0 ₇ Η ₂₅ Ν ₂ (M + H) ⁺ 257.2012, found 257.2007.

N-((4-Ethyl-3,5-dimethyl-pyrrol-2-ylidene)methyl)adamantan-l -amine hydrochloride (185)

^! H NMR (CDCI3, 400 MHz) δ 13.19 (s, 1H), 11.80 (d, / = 15.7 Hz, 1H), 7.44 (d, / = 15.7 Hz, 1H), 2.35 (q, = 7.3 Hz, 2H), 2.23 (s, 3H), 2.19 (s, 3H), 2.16 (s, 3H), 2.01 (d, = 2.5 Hz, 6H), 1.69 (m, 6H), 1.02 (t, = 7.3 Hz, 3H); ¹³ C NMR (CDCI3, 100 MHz) δ 145.7, 140.3, 138.1, 127.9, 119.7, 57.4, 42.2 (3C), 35.8 (3C), 29.4 (3C), 17.3, 14.9, 12.4, 9.8; HRMS (ESI) calcd for C19H29N2 (M + H) ⁺ 285.2325, found 285.2321.

N-((3-Methyl-4,5,6,7-tetrahydro-isoindol-l-ylidene)methyl)ad amantan-l-amine hydrochloride (186)

^! H NMR (CDCI3, 400 MHz) δ 13.17 (br s, 1H), 11.66 (d, = 15.6 Hz, 1H), 7.32 (d, / = 15.6 Hz, 1H), 2.59 (t, = 5.6 Hz, 2H), 2.33 (t, = 5.3 Hz, 2H), 2.28 (s, 3H), 2.17 (s, 3H), 1.98 (d, = 2.7 Hz, 6H), 1.68 (m, 10H); ¹³ C NMR (CDCI3, 100 MHz) δ 145.2, 140.8, 139.3, 123.4, 118.2, 56.9 42.0 (3C), 35.6 (3C), 29.2 (3C), 22.7, 22.3, 21.3, 20.5, 12.0; HRMS (ESI) calcd for C20H29N2 (M + H) ⁺ 297.2325, found 297.2321. Dimer of N-((4-ethyl-3,5-dimethyl-pyrrol-2-ylidene)methyl)adamantan-l - hydrochloride (187)

lH NMR (CDCI3, 400 MHz) δ 13.27 (s, 2H), 12.26 (d, 7 = 15.7 Hz, 2H), 7.54 (d, 7 = 15.7 Hz, 2H), 4.17 (s, 2H), 2.52 (q, 7 = 7.6 Hz, 4H), 2.23 (s, 6H), 2.19 (s, 6H), 2.05 (d, 7 = 2.7 Hz, 12H), 1.73 (m, 12H), 0.85 (t, 7 = 7.6 Hz, 6H); ¹³ C NMR (CDCI3, 100 MHz) δ 141.7 (2C), 141.5 (2C), 138.6 (2C), 128.8 (2C), 120.0 (2C), 57.7 (2C), 41.9 (6C), 35.5 (6C), 29.2 (7C), 17.2(2C), 14.4 (2C), 9.6 (2C); HRMS (ESI) calcd for C ₃ 7H ₅₃ N ₄ (M + H) ⁺ 553.4265, found 553.4307. Example 2

In Vitro Antimalarial Activity and Cytotoxicity of Prodiginine and Tambj amine Analogues In Vitro Antimalarial Activity. Antimalarial activity in vitro was determined by the Malaria SYBR Green I-based Fluorescence (MSF) assay described previously ³¹²¹ with minor modifications as previously described, ³¹¹³ and expressed as the compound concentration inhibiting growth by 50% (IC50).

HepG2 Cytotoxicity Assay. Drugs were dissolved in DMSO to make 10 mM stock solutions. Human hepatocarcinoma cells (HepG2) were maintained on RPMI-1640 medium supplemented with 10% fetal bovine serum at 37 °C in a humidified 5% CO2 atmosphere. Cells were seeded at a density of 2 x 10 ⁴ per well in 96-well flat-bottom tissue culture plates containing complete medium in a total volume of 160 μΐ/ννεΐΐ. The cells were allowed to attach at 37 °C overnight. On the following day, drug solutions (40 μΐ/ννεΐΐ) were serially diluted with complete culture medium across the plate. The plates were then incubated at 37 °C and 5% CO2 for another 24-36 h. Afterward, the medium was aspirated and replaced with complete RPMI medium (200 μΐ/ννεΐΐ), and the plates were incubated for an additional 24 h at 37 °C and 5% CO2. An aliquot of a stock solution of resazurin (Alamar Blue, prepared in 1 x PBS) was then added at 20 μΐ _^ per well (final concentration 10 μΜ), and the plates were returned to the incubator for 3 h. After this period, fluorescence in each well, indicative of cellular redox activity, was measured in a Gemini EM plate reader with excitation wavelength at 560 nm and emission wavelength at 590 nm. ^32a IC50 values were determined by nonlinear regression analysis of logistic concentration-fluorescence intensity curves (GraphPad Prism software). Biological Activity. The antimalarial activity of PGs, and modified PGs (premarineosins and marineosins) ⁴ were recently reported. The structural and functional diversity of PGs and TAs was expanded, where the ring-C of PGs was replaced by alkylamine, with enhanced antimalarial and cytotoxic activities. The structure-activity relationships (SARs) focused on various substitutions and positions of the ring-A, and -B and the nature of the alkylamines of TAs, and ring-B of PGs. Specifically, the modifications to the ring-B of TAs and PGs were designed in order to understand the structural requirements, as well as the necessity of the ring-B for the potent antimalarial activity. Various series of novel TAs and B-ring

functionalized PGs were synthesized and evaluated for antimalarial activity against the chloroquine- sensitive (CQ ^S ) D6, and the chloroquine-resistant (CQ ^R ) Dd2 and 7G8 strains of Pf with chloroquine (CQ) as a reference drug. ³¹ In parallel, the cytotoxicity of the most potent antimalarial PGs and TAs (IC50 < 250 nM) was tested against hepatocellular HepG2 cancer cell line using mefloquine (MQ) as a control drug (see Tables 1-6). ³²

In Vitro Antimalarial Activity of PGs (85-98). In previous work, synthetic PG 85 had shown an excellent potency against Pf strains D6 (CQ ^S ) and Dd2 (CQ ^R ) with great IC50 values (Table 1), and had the most favorable profile: 92% parasite reduction at 5 mg/kg/day, 100% reduction at 25 mg/kg/day in a P. yoelii murine patent infection without any evident weight loss or clinical overt toxicity. ¹³ To explore the N-alkyl effect on potency, initially two N-methylated analogues 86 and 87 of 85 were synthesized (Table 1). These compounds 86 and 87 led to a large decrease in the antimalarial activity (IC50 > 2250 nM) against three Pf strains D6, Dd2 and 7G8, demonstrating that both pyrrole NH groups (ring-A and -C) of the PGs are required for potent antimalarial activity and that support previous findings. ¹⁴ To investigate the importance of the methoxy group (OMe) on ring-B, two analogues 88 and 89, in which the OMe group is replaced by 4-chlorophenyl moiety and hydrogen (complete removal of OMe), respectively, were prepared and examined for in vitro antimalarial activity. A dramatic loss of potency was observed for both compounds 88 and 89, which have an IC50 of > 2500 nM against all tested Pf strains (Table 1). Interestingly, while replacing the OMe group by an ethyl unit as in 90 also led to reduced potency (90: IC50 =101 nM versus la: IC50 = 7.2 nM against D6), the reduction was modest (14-fold). This result demonstrated that a short aliphatic substitution at 4-position on the ring-B could replace the OMe group and retain activity. Together, these results highlighted the importance of the OMe or short alkyl group on the ring-B of PGs for potent antimalarial activity.

Tolerance of substitutions at 2 and 3 positions of the ring B was investigated. A series of novel B-ring functionalized PGs 91-98, in which the ring-B is substituted with either mono- and/or di-substituents at 3- and 4-positions, were generated and examined for their in vitro antimalarial activity (Table 1). A significant loss of potency (IC50 >1500 nM) was observed for 91 and 92, containing an iso-propyl, and tert-butyl groups, respectively, at 3-position on the ring-B. The adverse effect of the substitutions at 3-position on the ring-B was further confirmed by the introduction of the chloro (CI) substitution at 3-position of 90, as with the analogue 93, which had an IC50 of > 2500 nM against all strains (90: IC50 =101 nM versus 93: IC50 > 2500 nM), suggesting that the rigid bulky substitutions or chlorine moiety (EWG) at 3-position are not preferred (Table 1). To further investigate the impact of the short alkyl substituents at both the 3- and 4-positions on ring-B, a set of mixed analogues 94-98, which contain the 3-ethyl/4-methyl groups on the ring-B, was examined. Analogues 94 and 95, which have mono-alkyl groups at 5- position of the ring-C, showed a roughly 20-fold drop in activity as compared to

undecylprodiginine (la) (Table 1). Conversely, the analogue 96 containing a monoalkyl group at 3-position on the ring-C, showed higher potency (3-fold) than 95 against all tested Pf strains, while it had 9-fold lesser potency than the corresponding OMe group containing analogue (IC50 = 4.6 nM against D6 ¹³ ). Interestingly, the analogue 97, which has 3 -alkyl and 5-alkylaryl substituents on the ring-C, showed equipotent to the 85. While the analogue 98, which has 3,5- dialkylaryl substituents on ring-C, showed ~5-fold lower potency when compared to the corresponding OMe group containing analogue 85 (Table 1), again these results are consistent and support the findings that the 3,5-disubstitutions on ring-C are very important for potent activity. In summary, these SAR analyses of the ring-B functionalized PGs demonstrate that the short alkyl substitutions are well tolerated at 3/4-positions on the ring-B.

Tabl 1. In Vitro Antimalarial Activity and Cytotoxicity of PGs (85-98)

88: i = 3 = H, R ₂ = 4-CI-C ₆ H ₄

antimalarial activity

cpd R9 Rio Rn D6 Dd2 7G8 cytotoxicity SI ^b cLogP ^c

nM) ^a

HepG2

85

6.1 4.8 5.5 > 250000 > 40983 4.8

86 2250 > 2500 > 2500 nt ^d -

5.1

87 > 2500 > 2500 > 2500 nt - 5.3

88 > 2500 > 2500 > 2500 nt - 7.7

89 n-CnH23 H H H > 2500 > 2500 > 2500 nt - 5.2

90 n-CnH23 H Et H 101 66 51 18939 187 5.7

91 n-CnH23 H H -Pr 1586 1500 > 2500 nt - 6.3

92 n-CnH23 H H t-Bu > 2500 > 2500 > 2500 nt - 6.7

93 n-CnH23 H Et CI > 2500 > 2500 > 2500 nt - 5.8

94 n-CnH23 H Me Et 162 190 145 62000 383 6.1

95 n-CsHn H Me Et 127 216 132 71000 559 4.8

96 H n-CsHn Me Et 41 53 61 57200 1395 4.9

97 n-C ₇ Hi5 4- Me Et 6.5 7.0 5.9 82024 12619 6.7

98 Me Et 28 42 42 30600 1093 6.7

la 7.2 7.5 7.0 nt - 4.2

CQ 13 115 130 nt - 3.7

MQ nt nt nt 21800 - 5.3 ^a IC ₅ o values are the average of at least three determinations, each carried out in triplicate (+ 10%). In order to compare results run on different days, and with different batches of each stain; CQ was run as a positive control. All results obtained were 'normalized' to the CQ values of 13 nM for D6, 115 nM for Dd2 and 130 nM for 7G8.

bSI (selectivity index) = IC50 (cytotoxicity)/IC ₅ o (D6)

ccLogP values were calculated using ChemBioDraw Ultra software (version 14), ^d nt = not tested In Vitro Antimalarial Activity of 4-Substituted B-Ring Functionalized TAs (99- 129). Having determined the substituents impact on the antimalarial activity of the PGs, the complete replacement of the right-hand side alkylated pyrrole (ring-C) of PGs by alkylamines, providing the TAs, represented a potential opportunity to make potent and selective

antimalarials with the desired "druglike" properties. Specifically, lower molecular weight (MWT) and liphophilic properties (LogP) are the two key characteristics that determine adsorption, distribution, metabolism, excretion and toxicity (ADMET) liabilities, with some ADMET parameters depending more on MWT and some on LogP. ³³ Subsequent TA analogues 99-129 (Table 2), which have lower MWT (< 400) and LogP (< 4.2, except 114), were generated to obtain a SAR for the alkylamines in the place of ring-C and substituents at 4- position on the ring-B.

Initially, a series of new TAs 99-112, which have various alkyl/arylamines in the place of ring-C and the OMe group at the 4-position on the ring-B (as in natural products), were synthesized and evaluated for their in vitro antimalarial activity against Pf strains and the results are shown in Table 2. TAs 99-102 containing the n-alkylamines in the place of ring-C, exhibited good activity against all Pf strains, specifically, analogues 100 and 102 showed the highest potencies (IC50 < 50 nM) (Table 2). To probe the effect of cycloalkylamines in the place of ring-C/n-alkylamines on activity, another set of TAs 103-109 were synthesized (Table 2). Of these cycloalkylated TAs, analogues 108 and 109, which have the cyclooctylamine and 1- adamantylamine moieties, respectively, were the most potent antimalarial candidates (108: IC50 < 7.1 nM, and 109: IC50 < 3.8 nM against all tested Pf strains, see Table 2) with good selectivity and these results are more comparable to the potent PG 85 (IC50 < 6.1 nM), and the natural PG la (IC50 < 7.5 nM). These results, clearly demonstrated that the elongation of the cycloalkyl ring size (from cyclopropane, 103: IC50 = 2500 nM to 1-adamantyl, 109: IC50 < 3.1 nM) lead to an increase in activity (Table 2 and FIG. 5). The greatest loss of potency (IC50 > 2500 nM) was observed in 110, in which ring-C is replaced by piperidine moiety, suggesting that the free NH is required for the potent antimalarial activity. Replacement of cyclohexyl moiety with

benzylpiperidine as with 111 led to slightly reduced potency (106: IC50 = 49 nM versus 111: IC50 = 127 nM against D6). The analogue 112, which contain a 4-chloroaniline in the place of ring-C showed the moderate activity (Table 2). These results unequivocally demonstrate that the ring-C of PGs can be replaced by alkylamines, providing the novel TAs with retained and/or enhanced antimalarial and cytotoxic properties. To investigate the importance of the OMe group on ring-B of TAs, another set of TAs 113-119, in which the OMe group is replaced by 4-chlorophenyl moiety, was generated and examined for their in vitro antimalarial activity (Table 2). In vitro analysis of the activity of these compounds 113-119 against Pf, demonstrated activity (IC50 > 250 nM) significantly diminished when compared to the corresponding OMe group containing TAs (100, 102, and 105-109). This work suggested that the bulky aromatic substitution at 4-position on the ring-B had an adverse effect on antimalarial activity. Interestingly the replacement of the OMe group with short alkyl substituents (methyl/ethyl) also reduced the potency of the compounds 120-122, 124 and 125 (IC50 > 250 nM) (Table 2). Conversely, the adamantyl analogues 123 and 126, in which the OMe group is replaced by methyl and ethyl groups on the ring-B, respectively, showed a substantially higher potency against D6 strain (109: IC50 = 3.1 nM, versus 123: IC50 = 1.3 nM, 126: IC50 = 2.5 nM) with great selectivity. Complete removal of the OMe group on ring-B as with the analogues 127-129, resulted in the total loss of activity (127, 128: IC50 >

2500 nM vs 107: IC50 = 23 nM, 108: IC50 = 4.8 nM, and 129: IC50 = 341 nM vs 109: IC50 = 3.1 nM, 123: IC50 = 1.3 nM, 126: IC50 = 2.5 nM against D6). Together, these results again

demonstrate that the substituents at 4-position on the ring-B have an important role in potent antimalarial activity, and the OMe group can be replaced by short alkyl substituents

(methyl/ethyl), when 1-adamantylamine exists in the place of ring-C.

Table 2. In Vitro Antimalarial Activity and Cytotoxicity of 4-Substituted B-Ring Functionalized TAs (99-129)

antimalarial activity

compd Ri R4 D6 Dd2 7G8 cytotoxicity SI ^b cLogP ^c

99 OMe 11-C4H9 210 159 74.6 23000 109 0.08

100 OMe n-C ₆ Hi3 34 37 25 26700 785 0.9

101 OMe n-CsHn 345 177 69 nt ^d - 1.7

102 OMe n-CnH23 55 53 23 9800 178 3.0

103 OMe 2400 2500 946 nt - - 0.9

104 OMe 591 497 156 nt - - 0.4 105 OMe 68 84 45 30500 448 -0.03 106 OMe 49 71 30 15000 306 0.4 107 OMe 23 34 15 10100 439 0.8 108 OMe 4.8 7.1 7.5 9700 2021 1.2 109 OMe 3.1 2.6 3.8 3300 1064 0.7

110 OMe >2500 >2500 >2500 nt - -0.05 111 OMe - X 127 244 207 > 250000 > 1968 0.5

112 OMe 4-ClC ₆ H ₄ 255 368 314 nt - 1.1 113 4-ClC ₆ H ₄ n-C ₆ Hi3 1129 >2500 564 nt - 3.8 114 4-ClC ₆ H ₄ n-CnH23 664 >2500 663 nt - 5.9 115 4-ClC ₆ H ₄ 1218 >2500 510 nt - 2.9 116 4-ClC ₆ H ₄ 1025 >2500 415 nt - 3.3 117 4-ClC ₆ H ₄ 963 1250 348 nt - 3.7 118 4-ClC ₆ H ₄ 832 1135 316 nt - 4.1 119 4-ClC ₆ H ₄ >250 >250 126 nt - 3.6

120 Me n-CiiH 1167 1469 515 nt - 4.2

121 Me >250 >250 >250 nt - 2.0 122 Me >250 >250 >250 nt - 2.4 123 Me 1.3 15 4.3 6900 5308 1.8

124 Et >250 >250 >250 nt - 2.4 125 Et >250 >250 >250 nt - 2.8 126 Et 2.5 16 7.7 6100 2440 2.2

127 H >2500 >2500 >2500 nt - 1.8 128 H >2500 >2500 >2500 nt - 2.2 129 H 341 295 235 70000 205 1.6

CQ 13 115 130 nt - 3.7 MQ nt nt nt 21800 - 5.3 ^a IC ₅ o values are the average of at least three determinations, each carried out in triplicate (+ 10%). In order to compare results run on different days, and with different batches of each stain; CQ was run as a positive control. All results obtained were 'normalized' to the CQ values of 13 nM for D6, 115 nM for Dd2 and 130 nM for 7G8. ^b SI (selectivity index) = IC50 (cytotoxicity)/IC ₅ o (D6)

ccLogP values were calculated using ChemBioDraw Ultra software (version 14), ^d nt = not tested

In Vitro Antimalarial Activity of 3-Substituted B-Ring Functionalized TAs (130- 141). Having established the substitution pattern at 4-position on the ring-B and the terminal alkylamines (cycloheptyl-, cyclooctyl-, and 1-adamantylamines) as optimal, the effects of the substitution pattern at the 3-position were examined where the 4-position is vacant on the ring-B of the TAs (Table 3). To that end, a series of novel TAs 130-141 were generated in which the 3-position on the ring-B wass occupied with alkyl groups and screened for their antimalarial activity against Pf strains (Table 3). The greatest loss of potency was observed when the short alkyl (methyl/ethyl) groups moving from 4-position (121-126, Table 2) to the 3-position (130- 141, Table 3). Moreover, the adamantyl analogues 132 and 135, showed a significant decline in activity (132: IC50 = 106 nM vs 123: IC50 = 1.3 nM; and 135: IC50 = 117 nM, vs 126: IC50 = 2.5 nM against D6), and the analogue 141, had an almost total loss of activity (IC50 > 2500 nM). The one exception is the adamantyl analogue 138, containing an isopropyl group at 3-position on the ring-B, which showed the better potency (IC50 < 30 nM) against all tested Pf strains with good selectivity. These results show that generally alkyl substitutions at 3-position versus the 4- position, adversely affects the potency irrespective of the terminal alkylamines.

Table-3. In Vitro Antimalarial Activity and Cytotoxicity of 3-Substituted B-Ring Functionalized TAs (130-141)

antimalarial activity

compd 2 R ₄ D6 Dd2 7G8 cytotoxicity SI ^b cLogP ^c

130 Me Ό 2107 > 2500 2147 nt ^d - 2.1

131 Me 'r, 1376 > 250 1778 nt - 2.5

132 Me 106 170 95 30000 283 2.0

^

133 Et Ό 1305 523 1456 nt - 2.5

134 Et 'r, 1276 > 250 1326 nt - 3.0

135 Et 117 45 90 15200 130 2.4 136 i-Pr > 2500 1968 1980 nt - 2.9

137 f-Pr -Q 1079 665 1480 nt - 3.3

138 f-Pr ^y /^/> 26 20 31 18500 711 2.7

139 t-Bu > 2500 > 2500 > 2500 nt - 3.3

140 t-Bu -Q > 2500 > 2500 > 2500 nt - 3.8

141 t-Bu ^ > 2500 > 2500 > 2500 nt - 3.2

CQ 13 115 130 nt - 3.7

MQ nt nt nt 21800 - 5.3 ^a IC ₅ o values are the average of at least three determinations, each carried out in triplicate (+ 10%). In order to compare results run on different days, and with different batches of each stain; CQ was run as a positive control. All results obtained were 'normalized' to the CQ values of 13 nM for D6, 115 nM for Dd2 and 130 nM for 7G8.

bSI (selectivity index) = IC ₅ o (cytotoxicity )/IC ₅ o (D6)

ccLogP values were calculated using ChemBioDraw Ultra software (version 14), ^d nt = not tested

In Vitro Antimalarial Activity of 3,4-Disubstituted B-Ring Functionalized TAs (142-165). Exploration of the SARs around the ring-B of TAs indicated that the substitutions at 4-position were greatly favored compared to the 3-position (Tables 2 and 3). This finding is exemplified by the poor activity of the 3-substituted analogues (130-141) with the exception of 138. Tolerance for substitutions at both the 3- and 4-positions was investigated. A series of 3,4- disubstituted B-ring functionalized TAs 142-149 were synthesized, which have 3-ethyl, and 4- methyl groups on the ring-B (Table 4). Of these 3,4-disubstituted TAs, analogues 142-144, 148, and 149 with an n-alkyl, cyclopropyl, benzylpiperidine and morpholine moieties, respectively, showed the diminished activity (Table 4). Conversely, the analogues 145 and 146, which have cycloheptyl and cyclooctyl moieties, respectively, showed the highest potencies (Table 4) than those of the corresponding 3- and 4-monoalkyl substituted analogues (see Tables 2 and 3).

Significantly, the adamantyl analogue 147, showed comparable potency to that of the

corresponding 4-alkyl/methoxy substituted analogues (147: IC50 = 5.5 nM versus 109: IC50 = 3.1 nM, 123: IC50 = 1.3 nM, 126: IC50 = 2.5 nM against D6), and this potency is 5-20-fold greater than the corresponding 3-alkyl substituted analogues (147: IC50 = 5.5 nM versus 132:

IC50 = 106 nM, 135: IC50 = 117 nM, 138: IC50 = 26 nM against D6). Interchange of the methyl and ethyl groups between 3- and 4-positions on the ring-B as in 150-152 resulted in a ~2-fold decrease in potency (IC50 of 150-152 vs IC50 of 145-147). The short alkyl substitutions at both the 3- and 4-positions on the ring-B were well tolerated with comparable and/or enhanced activities. This allowed for a variety of different analogues to be synthesized with representative examples (153-165, Table 4). The analogues 153, 154, 156, 157, 159, and 160, which contain the same alkyl groups [methyl/ethyl/-(CH2-CH2)2-] at both 3- and 4-positions on the ring-B, and cycloheptyl/cyclooctylamines in the place of ring-C, were shown comparable and/or greater potency to the dissimilar alkyl groups at both 3- and 4-positions containing TAs. Significantly, the 1-adamantyl analogues 155 (IC50 < 2.4 nM), 158 (IC50 < 2.5 nM), and 161 (IC50 < 7.5 nM) showed enhanced (2-8-fold) or comparable potency against all tested Pf strains when compared to 147 (IC50 < 5.5 nM) and 152 (IC50 < 19 nM). The biggest potency loss occurred (IC50 > 2250 nM) when a chlorine atom was introduced at the 3-position on the ring-B as in 162-165 (IC50 of 156-158 vs 163-165, Table 4), and it is consistent with the observation that the chlorine atom (EWG) has an adverse effect at 3-position on the ring-B of PGs. Collectively, from the monoalkylated (Tables 2 and 3) and 3,4-dialkylated TAs (Table 4) the data clearly showed that the 3,4-disubstituted TAs containing cycloheptyl/cyclooctyl groups have significantly improved potency than the corresponding monoalkylated TAs (Tables 2 and 3), and these potencies were comparable to the corresponding OMe group containing analogues (Table 2). Notably, all the 1- adamantyl analogues, which have short (alkyl/methoxy) groups at 4-position (Table 2) and dialkyl groups at 3/4-positions (Table 4) on ring-B, showed the greatest activity with good selectivity.

Table-4. In Vitro Antimalarial Activity and Cytotoxicity of 3,4-Disubstituted B-Ring Functionalized TAs (142-165)

antimalarial activity

compd Ri R ₂ R ₄ D6 Dd2 7G8 cytotoxicity SI ^b cLogP ^c

HepG2

142 Me Et 11-C4H9 883 680 260 nt ³ - 2.0

143 Me Et n-CsHn 1166 633 244 nt - 3.7

144 Me Et ^v > 2047 2500 nt - 1.1

2500

145 Me Et 62 55 60 19200 310 2.7

146 Me Et 56 60 75 18900 337 3.1 147 Me Et 5.5 4.3 3.6 3300 600 2.6

148 Me Et > 1576 855 nt - 2.4

GJO

2500

149 Me Et > > > nt - 0.3

2500 2500 2500

150 Et Me Ό 150 200 117 15800 105 2.7

151 Et Me 111 201 128 23900 215 3.1

152 Et Me 19 14 14 4500 237 2.6

153 Me Me Ό 60 38 47 21300 355 2.3

154 Me Me 56 31 45 18100 323 2.7

155 Me Me 2.4 1.7 1.5 6400 2667 2.2

156 Et Et 54 30 88 16900 313 3.1

157 Et Et ^* o 39 26 58 13000 333 3.6

158 Et Et 1.6 1.0 2.5 3900 2437 3.0

159 -(CH ₂ -CH ₂ ) ₂ - 35 39 23 6200 177 2.6

XJ

160 -(CH ₂ -CH ₂ ) ₂ - ^* o 32 37 22 4600 144 3.1

161 -(CH ₂ -CH ₂ ) ₂ - 6.1 7.5 2.8 2700 442 2.5

162 Et Cl t-Bu 1217 > > nt - 1.7

2500 2500

163 Et CI XJ > > > nt - 2.4

2500 2500 2500

164 Et CI Ό > > > nt - 2.8

2500 2500 2500

165 Et CI 2300 > 2250 nt - 2.3

<I 2500

CQ 13 115 130 nt - 3.7

MQ nt nt nt 21800 - 5.3 ^a IC ₅ o values are the average of at least three determinations, each carried out in triplicate (+ 10%). In order to compare results run on different days, and with different batches of each stain; CQ was run as a positive control. All results obtained were 'normalized' to the CQ values of 13 nM for D6, 115 nM for Dd2 and 130 nM for 7G8.

bSI (selectivity index) = IC ₅ o (cytotoxicity)/IC ₅ o (D6)

ccLogP values were calculated using ChemBioDraw Ultra software (version 14), ^d nt = not tested

In Vitro Antimalarial Activity of A- and B-Ring Functionalized TAs (166-187).

After establishing the substitutions pattern at 3- and 4-positions on the ring-B of TAs, the importance of positioning of the ring-A at 2-position on the ring-B of TAs (Table 5) was investigated by keeping the 1-adamantylamine as an active pharmacophore for all analogues. The TAs 166-169, in which the ring-A (2-pyrrolyl moiety) is shifted from 2- to 3-position on the ring-B and are isomeric to 129, 123, 126, and 155 (Tables 2 and 4), respectively, were synthesized and tested against Pf strains (Table 5). It is noteworthy that the potency was significantly declined against all tested Pf strains after shifting the ring-A from 2- to 3-position (166-168: ICso > 2500 nM vs 123: ICso = 1.3 nM, 126: ICso = 2.5 nM, 129: ICso = 341 nM, and 169: ICso = 1418 nM vs 155: IC50 < 2.5 nM, against D6, Tables 2, 4 and 5). The importance of the location of nitrogen within ring-A was analyzed by moving from the 2'-position to the 3'- position (FIG. 1, and Table 5), where compound 170 showed a roughly 100-fold drop in activity (170: IC50 = 250 nM vs 155: IC50 < 2.5 nM, against D6, Tables 4 and 5). Alternatives to the ring-A at the 2 position of the ring-B were investigated. Replacement of the ring-A (2-pyrrolyl) by various 2-heteroaryl/phenyl moieties (compounds, 171-175) resulted in a decrease in antimalarial activity (IC50 of 171-175 vs 155 and 161). Notably, previous SAR investigations revealed that the ring-A (2-pyrrolyl moiety) of PGs provides optimal activity, ¹³ ' ¹⁴ and the current results also suggest the importance of the ring-A of TAs for the potent activity. Alkylation (methylation) on the NH group of the ring-A as in 176, resulted in a large decrease in potency (176: IC50 > 2500 nM vs 155: IC50 < 2.5 nM), suggest that the pyrrole NH (ring-A) of the TAs is important for potent antimalarial activity. Conversely, the analogues 177-181, which contain C- alkyl moieties on the ring-A, retained the potency against all tested Pf strains, suggesting that the alkyl groups are well tolerated on the ring-A.

To further investigate the exact role of the ring-A of TAs on potency, a set of mixed alkylated analogues 182-186, in which the ring-A is completely removed from the core moiety of TAs, were examined. Complete removal of the substitutions on the ring-B, dramatically reduced the potency of the compound 182 (IC50 > 2500 nM). Incorporation of the substitutions into the ring-B as in 183-186 (from mono- to tri-alkyl) resulted in a large increase in potency (Table 5), whereas the dimer 187 of the 185 showed the poorest activity. It is noteworthy that the analogues 185 and 186, which contain a monopyrrole with trialkyl substituents and an enamine moiety, showed the comparable potency to that of the corresponding bipyrrole TAs. These results demonstrated that the ring-A is not essential for the antimalarial activity, but both the trialkylated monopyrrole and enamine moitety are important. In summary, structure pruning of PGs has shown that in vitro potency can be retained and/or enhanced when moving from a tripyrrole (PGs) to bipyrrole (TAs) and even to a monopyrrole as shown in Scheme 12.

Prodiginine (98) Tambjamine (147) Novel analogue (185) IC ₅₀ = 28 nM (D6) IC ₅₀ = 5.5 nM (D6) IC50 = 33 nM (D6)

Scheme 12. Structure pruning approach of the lead PG compounds (98) Table 5. In Vitro Antimalarial Activity and Cytotoxicity of A- and B-Ring Functionalized TAs (166-187)

antimalarial activity

(IC ₅ o in nM) ^a

compd Ri R ₂ R ₃ D6 Dd2 7G8 cytotoxicity SI ^b cLogP ^c

(IC ₅ o in nM)' (D6)

HepG2

166 H H > 2500 > 2500 > 2500 nt ^u 1.3

167 Me > 2500 > 2500 > 2500 nt 1.4

168 Et o > 2500 1233 > 2500 nt 1.9

169 Me o 1418 1736 2005 nt 1.6

170 Me Me 250 328 215 nt 2.1 171 Me Me 647 1716 415 nt 2.2

172 Me Me 415 273 2282 nt 3.6

173 Me Me 1141 831 >2500 nt 3.6

174 Me Me 318 388 161 nt 3.2

175 -(CH ₂ -CH ₂ ) ₂ - 1335 1103 946 nt 1.9

176 Me Me > 2500 > 2500 > 2500 nt 2.4

177 Me Me 2.1 2.3 0.5 3600 1714 3.0

178 Me Me < 2.5 < 2.5 < 2.5 1235 > 494 3.7 179 Me Me 4.8 4.0 2.8 3825 797 3.1

180 Me Me J 27 75 12 17920 664 3.0

181 Me Me ^~~~ V- 58 92 48 21323 368 3.9 it

182 H H H > 2500 > 2500 > 2500 nt - 1.2

183 H H Me 2100 1682 > 2500 nt - 1.3

184 Me H Me 315 268 399 nt - 1.5

185 Me Et Me 33 80 33 29900 906 2.2

186 -(CH ₂ -CH ₂ ) ₂ - Me Me 64 60 5430 89 2.2

187 Me Et > 2500 > 2500 > 2500 nt 4.5

CQ 13 115 141 nt - 3.7

MQ nt nt nt 21000 - 5.3 ^a IC ₅ o values are the average of at least three determinations, each carried out in triplicate (+ 10%). In order to compare results run on different days, and with different batches of each stain; CQ was run as a positive control. All results obtained were 'normalized' to the CQ values of 13 nM for D6, 115 nM for Dd2 and 130 nM for 7G8.

bSI (selectivity index) = IC ₅ o (cytotoxicity )/IC ₅ o (D6)

ccLogP values were calculated using ChemBioDraw Ultra software (version 14), ^d nt = not tested

In Vitro Antimalarial Activity of TA like Analogues (190, 191 and 194-196), in which the ring-B is replaced by an alkylamide/amine linkage. Detailed SAR explorations around the ring-A and -B and nature of alkylamines of TAs led to a robust understanding of the structural features that provide potent antimalarial activity. Further investigation explored whether any linkage (total replacement of ring-B) between two of the most active

pharmacophores (i.e. 2-pyrrolyl, and 1-adamantyl moieties) is tolerated. A set of novel analogues 190, 191 and 194-196, in which ring-B is completely replaced by an

alkylamide/amine linkage, were generated and screened for their antimalarial activity against Pf strains (Table 6). None of these analogues showed activity (IC50 > 2500 nM, Table 6). This data confirmed that the ring-B between ring-A and alkylamine plays an important role in the antimalarial activity of TAs and PGs as well. Table 6. In Vitro Antimalarial Activity of TA like Analogues (190, 191 and 194-196)

antimalarial activity

compd linkage D6 Dd2 7G8 cLogP ^b

190 > 2500 > 2500 > 2500 0.4

191 > 2500 > 2500 > 2500 1.6

H

194 > 2500 > 2500 > 2500 0.7

195 O > 2500 > 2500 > 2500 0.6

H

196 ^{> 250} ° ^{> 2500} > 2500 2.1

CQ - 13 115 130 3.7 ^a IC ₅ o values are the average of at least three determinations, each carried out in triplicate (+ 10%). In order to compare results run on different days, and with different batches of each stain; CQ was run as a positive control. All results obtained were 'normalized' to the CQ values of 13 nM for D6, 115 nM for Dd2 and 130 nM for 7G8.

bcLogP values were calculated using ChemBioDraw Ultra software (version 14)

Example 3

In Vivo Efficacy in Mice Models

Given the attractive antiplasmodial activity of several PGs and TAs against CQ ^S -D6, CQ ^R -Dd2, and 7G8 strains of P. falciparum along with favorable toxicological properties against hepatocellular HepG2 cancer cell line and lower MWT and lipophilicity properties, an in vivo proof of concept study in a murine P. yoelii model was undertaken with the most potent and selective analogues 98, 100, 105, 108, 109, 123, 145, 177, and 185, using side by side comparison with previous lead PG 85 ¹³ and CQ as a reference drug (Table 7). In vivo efficacy was determined in a murine P. yoelii model, ³⁴ in which animals were randomly placed in groups of four and administered test drugs range of 5 mg/kg to 100 mg/kg by oral gavage on four sequential days following the day of inoculation. The in vivo activity of selected PGs and TAs was assessed against the blood stages using a modified 4-day test. ³⁴ 4- to 5-week-old female CF1 mice (Charles River Laboratories) were infected intravenously with 2.5 x 10 ⁵ P. yoelii (Kenya strain, MR4 MRA-428) parasitized erythrocytes from a donor animal. Drug administration commenced the day after the animals were inoculated (day 1). The test compounds were dissolved in PEG-400 and administered by oral gavage once daily for four successive days; chloroquine phosphate was used as a positive control. Blood for blood film analysis and body weights were obtained on the day following the last dose and then at weekly intervals through day 28. Blood films were Giemsa stained and examined microscopically to determine the levels of parasitemia. These blood samples were collected from the tail vein with the aid of a syringe-needle. All mice were observed daily to assess their clinical signs, which were recorded. Animals with observable parasitemia following the experiment were euthanized; animals cleared of parasites from their bloodstream were observed daily with assessment of parasitemia performed weekly until day 28 at which point the animal(s) were scored as cured of infection, and the animals were euthanized. All treated mice with a negative smear on day 28 were considered cured (100% protection). ED50 values

(mg/kg/day) were derived graphically from the dose required to reduce parasite burden by 50% relative to drug-free controls.

The in vivo data are expressed as ED50 values and reflect the dose (estimated from dose-response curves) for suppression of parasitemia by 50% relative to vehicle-only controls as assessed on day 5 of each study. In these experiments, the animals with parasitemia either on day 5 or later were euthanized and the parasitemia free animals were kept in observation until day 28. Drug treated animals that were parasitemia free on day 28 of the experiment are defined as "cures", and the amount of drug that was needed to achieve a cure is referred to as the "nonrecrudescence dose" (NRD).

Following four once-daily doses of PGs 85 and 98 at 5 mg/kg, each reduced parasitemia by 90% and 66% on day 5, respectively, and parasitemia free animals were observed at 25, and 50-100 mg/kg. However, none of these animals were cured, while the CQ was also not curative in this model even at doses as high as 64 mg/kg/day (Table 7). The TA analogues 100, 105, and 108, each reduced parasitemia > 90% after 5, 25 and 50 mg/kg x 4 days dosing, and at the higher dose (100 mg/kg x 4 days) these reduced parasitemia 100% on day 5. Intriguingly, the

TA 109 with good in vitro potency, showed much less efficacy with an ED50 value of 84 mg/kg/day, which may relate to low aqueous solubility and/or poor oral bioavailability (Table

7). Interestingly the analogue 123, in which the methyl group of ring-B is replaced with the OMe group of 109, showed improved efficacy at all doses; specifically 100% reduction was observed at 50 mg/kg x 4 days on day 5. Of these TAs, the analogue 145 with 3-ethyl/4-methyl substitution pattern on the ring-B and the cycloheptylamine in the place of ring-C, provided an excellent in vivo efficacy against P. yoelii in mice with an ED50 value of < 2.5 mg/kg/day, and it cleared all parasitemia on day 5 after dosing 5 mg/kg to 100 mg/kg x 4 days. Indeed, the compound 145 provided parasite-free cures on day 28 (100% protection to malaria-infected mice) at 25 and 50 mg/kg/day, without evident weight loss and toxicity. In separate experiments, a single oral dose (80 mg/kg) of KAR425 (145) was also used. The preliminary experiments demonstrated that KAR425 is also curative in this model and two of four mice were cured with no obvious signs of toxicity or behavior change and further higher dose studies are underway. The analogues 177 and 185 showed 100% parasitemia reduction on day 5 after 25-100 mg/kg and 100 mg/kg dosing, respectively, however these were not curative in this model.

Genotoxicity: More promising compound 145 was tested using the Ames assay (EPBI Inc.) at concentration of 10 uM, with and without S9 activation, against Salmonella typhimurium TA100 and TA98. Results in general were negative. There was no increase over the background reversion rate, and compound 145 was judged to be non-genotoxic.

Table 7. In Vivo Antimalarial Efficacy of PGs and TAs in a Murine P. yoelii

dose % suppression of

compd compd structure (mg/kg x 4 parasitaemia on ED50

code names days) day 5 ^b (mg/kg/day) control - - PEG-400

185 KAR765 5 24 45

25 17

50 67

100 100

CQ 1 65 2.2

4 94

16 100

64 100

''previous lead compound, ^{13 b} % suppression of parasitemia = 100 x parasitemia control group-parasitemia treated group/parasitemia control group, ^c provided cures (100% protection to malaria-infected mice)

VII. DISCUSSION

The synthesis and antimalarial activity of the novel class of potent tambjamines (TAs) and B-ring functionalized prodiginines (PGs) are reported. The compounds were synthesized via simple and inexpensive chemical procedures using easily available building blocks to respond to the demand for low-cost novel antimalarial agents. When compared to PGs, ^{13 14} embodiments of the disclosed TAs exhibited marked improvements with regard to the color properties, in vitro potency, selectivity, and in vivo efficacy. Several key findings emerged from these studies: i) the alkylated pyrrole (ring-C (see, FIG. 1)) can be replaced by an alkyl/cycloalkylamine, providing for TAs with retained and/or enhanced antimalarial activity, ii) the OMe group at the 4-position on the ring-B, between ring- A and ring-C/alkylamine of PGs/TAs, can be replaced with short alkyl substitutions either at 4-position (R ¹ of Formula I) or 3- and 4-positions (R ¹ and R ² of Formula I) without impacting in vitro potency, iii) a 2-pyrrolyl moiety (ring-A) linked at the 2- position (R ³ of Formula I) on the ring-B increases potency, and it can be substituted with alkyl groups. In addition, these analogues are equally effective against P. falciparum pansensitive D6 and MDR Dd2 and 7G8 strains. Some of these analogues have shown very promising in vivo efficacy in mice. Specifically, the KAR425 (145) TA offered greater efficacy than previously observed for any tripyrrole PG, providing 100% protection to malaria-infected mice until day 28 at doses of 25 and 50 mg/kg x 4days and was also curative in this model in a single oral dose (80 mg/kg). KAR425 stands out as an excellent lead compound, with low molecular weight (< 300), good lipophilicity (cLogP < 2.7), oral efficacy, no obvious signs of toxicity, and particularly non-geno toxic.

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In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims.