PROSTAGLANDIN E ₁ AND E ₂ ANALOGS FOR THE TREATMENT OF VARIOUS MEDICAL CONDITIONS

Cross Reference to Related Applications

[0001] The present invention claims priority from U.S. Provisional

Application No. 60/987,859 filed November 14, 2007 entitled "Prostaglandin E ₁ and E ₂ Derivatives as Selective E ₂ Agonists for Medicinal Treatment," and U.S. Provisional Application No. 61/037,493 filed March 18, 2008 entitled "Prostaglandin Ei and E ₂ Derivatives as Selective E ₂ Agonists for Medicinal Treatment."

Field of the Invention

[0002] The present invention relates to pharmaceutically active compounds and more particularly to prostaglandin analogs with selectivity for prostaglandin E (EP) receptors and demonstrating EP agonist activity, and the use of such compounds and compositions thereof for the treatment of various medical conditions.

Background of the Invention

[0003] Prostanoids are ubiquitous lipid mediator biomolecules involved in numerous physiological processes, such as the contraction and relaxation of smooth muscle, vasodilation, vasoconstriction, pain, regulation of blood pressure, and modulation of inflammation. Prostanoids are a family of eicosanoids that comprise prostaglandins (PGs), prostacyclins (PGIs), and thromboxanes (Txs). Their receptors belong to the G-protein coupled receptor (GPCR) superfamily of receptors and may be grouped into five classes, namely, prostaglandin D (DP), prostaglandin E (EP), prostaglandin F (FP), prostaglandin I (IP), and Thromboxane A (TP) based on their sensitivity to five naturally occurring prostanoids, PGD ₂ , PGE ₂ , PGF _2α , PGI ₂ , and TxA ₂ ,

respectively (Coleman, R. A., Prostanoid Receptors. IUPHAR compendium of receptor characterization and classification, 2 ^nd edition, 338-353, 2000). EP receptors have been characterized into four subtypes EP-i, EP ₂ , EP ₃ , and EP ₄ . Each subtype has been cloned and is distinct at both a molecular and pharmacological level.

[0004] Prostanoids are synthesized from essential fatty acids comprising twenty carbon atoms, such as arachidonic acid and 8,1 1 ,14- eicosatrienoic acid. Prostanoids are synthesized in response to both extracellular and intracellular stimuli and are then rapidly released from the cells. In general, the short half-lives of most prostanoids ensure they act near the sites of their biosynthesis.

[0005] Prostaglandin E ₂ (PGE ₂ ) is a potent endogenous EP receptor agonist derived from arachidonic acid, shown below, and possesses two carbon-carbon double bonds, one in each the α-chain and ω-chain, and is thus called a "Series 2" prostaglandin.

[0006] Prostaglandin Ei (PGE-i) is derived from 8,1 1 , 14-eicosatrienoic acid and possesses only one carbon-carbon double bond, located in the ω- chain, and is thus called a "Series 1" prostaglandin.

[0007] Both prostanoid and non-prostanoid EP receptor agonists are known. EP receptor agonists may have a number of utilities. These include, but are not limited to treatment of influenza (WO 2008/058766), bone fracture healing (Li, M., et al., J. Bone Miner. Res., 18(77), 2003, 2033-2042; Paralkar, V. M., PNAS, ^ 00{11), 2003, 6736-6740; WO 2002/24647; WO 1998/27976), bone disease (WO 2002/24647), glaucoma (WO 2008/015517; WO 2007/027468; WO 2003/040126), ocular hypertension (WO 2003/040126), dysmenorrhoea (WO 2003/037433), pre-term labor (GB 2 293 101), immune disorders (WO 2003/037433), osteoporosis (WO 1998/27976; WO 2001/46140), asthma (WO 2003/037433), allergy (WO 2003/037433), fertility (Breyer, R. M., et al., Ann. N. Y. Acad. Sci., 905, 2000, 221-231), male sexual dysfunction (WO 2000/40248), female sexual dysfunction (United States Patent 6,562,868), periodontal disease (WO 2000/31084), gastric ulcer (United States Patent 5,576,347), and renal disease (WO 1998/34916). EP receptor agonists may also be useful for expansion of hematopoietic stem cell

populations (WO 2008/073748; North, T. E., et al., Nature, 447, 2007, 1007- 1011 ).

Summary of the Invention

[0008] The exemplary embodiments may be directed to compounds of structural formula (I) that may be used to expand hematopoietic stem cell populations or to treat or prevent influenza, bone fracture, bone disease, glaucoma, ocular hypertension, dysmenorrhoea, pre-term labor, immune disorders, osteoporosis, asthma, allergy, male sexual dysfunction, female sexual dysfunction, periodontal disease, gastric ulcer, renal disease, or other EP receptor-mediated conditions wherein C ⁹ , C ¹¹ , R ¹ , Z ¹ , Z ² , Z ³ , Z ⁴ , Z ⁵ , Z ⁶ , Z ⁷ , m and n are defined herein:

I

[0009] Another aspect of the embodiment is a pharmaceutical composition comprising a pharmaceutically effective amount of a compound according to formula (I), any stereoisomer or geometric isomer thereof, or a prodrug thereof, or a hydrate or solvate thereof, or a pharmaceutically acceptable salt thereof, in admixture with a pharmaceutically acceptable carrier.

[00010] Another aspect of the embodiment is directed to a method of expanding hematopoietic stem cell populations in a culture or patient in need thereof by administering to the culture or patient a compound according to formula (I), any stereoisomer or geometric isomer thereof, or a prodrug thereof, or a hydrate or solvate thereof, or a pharmaceutically acceptable salt thereof.

[00011] Another aspect of the embodiment is directed to a method of treating or preventing influenza, bone fracture, bone disease, glaucoma, ocular hypertension, dysmenorrhoea, pre-term labor, immune disorders, osteoporosis, asthma, allergy, male sexual dysfunction, female sexual dysfunction, periodontal disease, gastric ulcer, renal disease, or other EP receptor-mediated conditions in a patient in need thereof by administering to the patient a compound according to formula (I), any stereoisomer or geometric isomer thereof, or a prodrug thereof, or a hydrate or solvate thereof, or a pharmaceutically acceptable salt thereof. [00012] Other exemplary embodiments of the invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while disclosing exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

Detailed Description of the Invention

[00013] The exemplary embodiments are directed to a compound of formula (I), their preparation, pharmaceutical compositions comprising these compounds, and their pharmaceutical use in the prevention and treatment of EP receptor-mediated diseases or conditions. The compounds of formula (I) are shown below:

wherein:

dashed bonds may each independently represent a second carbon-carbon bond in order to give a carbon-carbon double bond with either (E) or (Z) geometry or may be ignored in order to give a carbon-carbon single bond;

C9 and C11 each is independently C=CH2, C=O, CF2, CHF (any stereoisomer), or C(H)OH (any stereoisomer) with the proviso that C9 does not equal C11 , and also with the proviso that when one of either C9 or C11 is C=O, and the other is C(H)OH, at least one of Z2, Z3, Z4, and Z5 is fluorine, and also with the proviso that when one of either C9 or C11 is CHF, the other is not C(H)OH;

R ¹ is CO ₂ R ³ , CH ₂ OR ³ , CONR ⁴ R ⁵ , COCH ₂ OH, CONR ⁴ SO ₂ R ⁵ , P(O)(OR ⁴ ) ₂ , or

Z ¹ are hydrogen or fluorine;

Z ² and Z ³ each is independently hydrogen or fluorine;

Z ⁴ and Z ⁵ each is independently hydrogen, fluorine, hydroxy, or methyl, or together are an oxygen atom that form a carbonyl group with the adjoining carbon atom of the ω chain;

Z ⁶ and Z ⁷ each is independently hydrogen, fluorine, hydroxy, or methyl, or together are an oxygen atom that form a carbonyl group with the adjoining carbon atom of the ω chain;

[00014] The exemplary embodiment above may also include any stereoisomer or geometric isomer thereof, or an equivalent thereof, or a prodrug thereof, or a hydrate or solvate thereof, or a pharmaceutically acceptable salt thereof.

[00015] Another exemplary embodiment may be directed to a compound of formula (I) wherein C ⁹ is C=O and C ¹¹ is C=CH ₂ .

[00016] Another exemplary embodiment may be directed to a compound of formula (I) wherein C ⁹ is C(H)OH and C ¹¹ is C=CH ₂ .

[00017] Another exemplary embodiment may be directed to a compound of formula (I) wherein C ⁹ is C=CH ₂ and C ¹¹ is C=O.

[00018] Another exemplary embodiment may be directed to a compound of formula (I) wherein C ⁹ is C=O and C ¹¹ is CF ₂ .

[00019] Another exemplary embodiment may be directed to a compound of formula (I) wherein C ⁹ is C(H)OH and C ¹¹ is CF ₂ .

[00020] Another exemplary embodiment may be directed to a compound of formula (I) wherein C ⁹ is CF ₂ and C ¹¹ is C=O.

[00021] Another exemplary embodiment may be directed to a compound of formula (I) wherein C ⁹ is CF ₂ and C ¹¹ is C(H)OH.

[00022] Another exemplary embodiment may be directed to a compound of formula (I) wherein C ⁹ is C=O and C ¹¹ is CHF.

[00023] Another exemplary embodiment may be directed to a compound of formula (I) wherein C ⁹ is CHF and C ¹¹ is C=O.

[00024] Another exemplary embodiment may be directed to a compound of formula (I) wherein R ¹ is CO ₂ H.

[00025] Another exemplary embodiment may be directed to a compound of formula (I) wherein R ¹ is CO ₂ Pr.

[00026] Another exemplary embodiment may be directed to a compound of formula (I) wherein R ¹ is CON(H)Et.

[00027] Another exemplary embodiment may be directed to a compound of formula (I) wherein R ¹ is CON(H)SO ₂ Me.

[00028] Another exemplary embodiment may be directed to a compound of formula (I) wherein R ¹ is CH ₂ OH.

[00029] Another exemplary embodiment may be directed to a compound

[00030] Another exemplary embodiment may be directed to a compound of formula (I) wherein Z ¹ is hydrogen.

[00031] Another exemplary embodiment may be directed to a compound of formula (I) wherein Z ¹ is fluorine.

[00032] Another exemplary embodiment may be directed to a compound of formula (I) wherein Z ² is fluorine and Z ³ is hydrogen, or an equivalent thereof, or a hydrate or solvate thereof, or a pharmaceutically acceptable salt thereof.

[00033] Another exemplary embodiment may be directed to a compound of formula (I) wherein Z ² is hydrogen and Z ³ is fluorine.

[00034] Another exemplary embodiment may be directed to a compound of formula (I) wherein each Z ⁴ and Z ⁵ is fluorine.

[00035] Another exemplary embodiment may be directed to a compound of formula (I) wherein each Z ⁴ and Z ⁵ is methyl.

[00036] Another exemplary embodiment may be directed to a compound of formula (I) wherein Z ⁴ is hydroxy and Z ⁵ is methyl.

[00037] Another exemplary embodiment may be directed to a compound of formula (I) wherein Z ⁴ and Z ⁵ together is an oxygen atom that form a carbonyl with the adjoining carbon atom.

[00038] Another exemplary embodiment may be directed to a compound of formula (I) wherein each Z ⁶ and Z ⁷ is hydrogen.

[00039] Another exemplary embodiment may be directed to a compound of formula (I) wherein each Z ⁶ and Z ⁷ is fluorine.

[00040] Another exemplary embodiment may be directed to a compound of formula (I) wherein each Z ⁶ and Z ⁷ is methyl.

[00041] Another exemplary embodiment may be directed to a compound of formula (I) wherein Z ⁶ is hydroxy and Z ⁷ is hydrogen.

[00042] Another exemplary embodiment may be directed to a compound of formula (I) wherein Z ⁶ is hydroxy and Z ⁷ is methyl.

[00043] Another exemplary embodiment may be directed to a compound of formula (I) wherein Z ⁶ is methyl and Z ⁷ is hydrogen.

[00044] Another exemplary embodiment may be directed to a compound of formula (I) wherein Z ⁶ and Z ⁷ together is an oxygen atom that form a carbonyl with the adjoining carbon atom.

[00045] Another exemplary embodiment may be directed to a more specific embodiment of the compound of formula (I), namely to a compound of formula (II):

(II) or an equivalent thereof, or a hydrate or solvate thereof, or a pharmaceutically acceptable salt thereof.

[00046] Another exemplary embodiment may be directed to a more specific embodiment of the compound of formula (I), namely to a compound of formula (III):

(III) or an equivalent thereof, or a hydrate or solvate thereof, or a pharmaceutically acceptable salt thereof.

[00047] Another exemplary embodiment may be directed to a more specific embodiment of the compound of formula (I), namely to a compound of formula (IV):

(IV) or an equivalent thereof, or a hydrate or solvate thereof, or a pharmaceutically acceptable salt thereof.

[00048] Another exemplary embodiment may be directed to a more specific embodiment of the compound of formula (I), namely to a compound of formula (V):

(V) or an equivalent thereof, or a hydrate or solvate thereof, or a pharmaceutically acceptable salt thereof.

[00049] Another exemplary embodiment may be a compound selected from the group consisting of: (2)-2 _I 2-difluoro-7-((1R,2R)-2-((S,£)-3- hydroxyoct-1 -enyO-S-methylene-δ-oxocyclopentyOhept-δ-enoic acid; (Z)-7- ((1 R2R)-2-((1R,3S)-1-fluoro-3-hydroxyoctyl)-3-methylene-5- oxocyclopentyl)hept-5-enoic acid; (Z)-7-((1R,2R)-2-((1 S,3S)-1-fluoro-3- hydroxyoctyl)-3-methylene-5-oxocyclopentyl)hept-5-enoic acid; (Z)-7- ((1f?,2R)-2-((2R,3S)-2-fluoro-3-hydroxyoctyl)-3-methylene-5- oxocyclopentyl)hept-5-enoic acid; (Z)-7-((1 R2R)-2-((2S,3S)-2-fluoro-3- hydroxyoctyl)-3-methylene-5-oxocyclopentyl)hept-5-enoic acid; (Z)-7- ((^^^^-(O-S.S-difluorooct-i-enyO-S-methylene-S-oxocyclopenty Ohept-δ- enoic acid; (Z)-7-((1 ft,2ft)-2-((R,E)-3-hydroxy-3-methyloct-1 -enyl)-3- methylene-5-oxocyclopentyl)hept-5-enoic acid; (Z)-7-((1 R,2R)-2-((R,E)-3- hydroxy-4,4-dimethyloct-1-enyl)-3-methylene-5-oxocyclopentyl )hept-5-enoic acid; (Z)-7-((1R,2fi)-2-((R,E)-4,4-difluoro-3-hydroxyoct-1-enyl)-3 -methylene-5- oxocyclopentyl)hept-5-enoic acid; and (Z)-7-((1R,2R)-2-((S,£)-3-hydroxy-3- methyloct-1-enyl)-3-methylene-5-oxocyclopentyl)hept-5-enoic acid; or an equivalent thereof, or an isopropyl ester thereof, or a hydrate, solvate, or a pharmaceutically acceptable salt thereof.

[00050] Another exemplary embodiment may be a compound selected from the group consisting of: (Z)-7-((1R2R)-2-((£)-3,3-difluorooct-1-enyl)-5- methylene-3-oxocyclopentyl)hept-5-enoic acid; (Z)-7-((1 f?,2f?)-3,3-difluoro-2- ((S,E)-3-hydroxy-3-methyloct-1-enyl)-5-oxocyclopentyl)hept-5 -enoic acid; (Z)- 7-((1R,2R,3R)-2-((E)-3,3-difluorooct-1-enyl)-3-hydroxy-5- methylenecyclopentyl)hept-5-enoic acid; [Z)-7-[[1R,2R,3R)-3-f\uoro-2-[[R,E)- 3-hydroxy-4,4-dimethyloct-1 -enyO-δ-oxocyclopentyOhept-δ-enoic acid; [Z)-I- ((1R,2R,3S)-3-fluoro-2-((R,E)-3-hydroxy-4,4-dimethyloct-1-en yl)-5- oxocyclopentyl)hept-5-enoic acid; (Z)-7-((1f?,2/ ^: ?,5f?)-5-fluoro-2-((R,E)-3- hydroxy-4,4-dimethyloct-1 -enyl)-3-oxocyclopentyl)hept-5-enoic acid; [Z)-I- ((1R,2R,5S)-2-((£)-3,3-difluorooct-1-enyl)-5-hydroxy-3- methylenecyclopentyl)hept-5-enoic acid; (Z)-7-((1 R,2f?,5S)-3,3-difluoro-5- hydroxy-2-((f?,E)-3-hydroxy-4,4-dimethyloct-1-enyl)cyclopent yl)hept-5-enoic acid; (Z)-7-((1R,2/?,5S)-5-fluoro-2-((RE)-3-hydroxy-4,4-dimethyloc t-1-enyl)-3- oxocyclopentyl)hept-5-enoic acid; (Z)-7-((1 R,4R,5f?)-2,2-difluoro-4-hydroxy-5- ((f?,E)-3-hydroxy-4,4-dimethyloct-1-enyl)cyclopentyl)hept-5- enoic acid; and (Z)-7-((1R5R)-2,2-difluoro-5-((S,E)-3-hydroxy-3-methyloct-1- enyl)-4- oxocyclopentyl)hept-5-enoic acid; or an equivalent thereof, or an isopropyl ester thereof, or a hydrate, solvate, or a pharmaceutically acceptable salt thereof.

[00051] The exemplary embodiments may also be directed to a method of preventing or treating a disease or condition mediated at least in part by agonism of an EP receptor, in a subject in need of such treatment, comprising administering to the subject a therapeutically effective amount of a compound of any exemplary embodiment of formula (I), or a pharmaceutically acceptable salt, hydrate, or solvate thereof; the use of a compound of any exemplary embodiment of formula (I), or a pharmaceutically acceptable salt, hydrate, or solvate thereof, for the manufacture of a medicament for preventing or treating a disease or condition mediated at least in part by agonism of an EP receptor; a compound of any exemplary embodiment of formula (I), or a pharmaceutically acceptable salt, hydrate, or solvate thereof, for use as a medicament; a compound of any exemplary embodiment of formula (I), or a pharmaceutically acceptable salt, hydrate, or solvate thereof, for use in the prevention or treatment of a disease or condition mediated at least in part by

agonism of an EP receptor; a pharmaceutical composition comprising a compound of any exemplary embodiment of formula (I), or a pharmaceutically acceptable salt, hydrate, or solvate thereof, and a pharmaceutically acceptable excipient; a pharmaceutical composition for the prevention and treatment of a disease or condition mediated at least in part by agonism of an EP receptor comprising a compound of any exemplary embodiment of formula (I), or a pharmaceutically acceptable salt, hydrate, or solvate thereof. [00052] The diseases and conditions mediated at least in part by agonism of an EP receptor may include allergy and allergic inflammation. Diseases and conditions of this kind may be allergic respiratory conditions such as allergic rhinitis, nasal congestion, rhinorrhea, perennial rhinitis, nasal inflammation, asthma of all types, chronic obstructive pulmonary disease (COPD), chronic or acute bronchoconstriction, chronic bronchitis, small airways obstruction, emphysema, chronic eosinophilic pneumonia, adult respiratory distress syndrome, exacerbation of airways hyper-reactivity consequent to other drug therapy, airways disease that may be associated with pulmonary hypertension, acute lung injury, bronchiectasis, sinusitis, allergic conjunctivitis, or atopic dermatitis, particularly asthma or chronic obstructive pulmonary disease.

[00053] Types of asthma may include atopic asthma, non-atopic asthma, allergic asthma, atopic bronchial IgE-mediated asthma, bronchial asthma, essential asthma, true asthma, intrinsic asthma caused by pathophysiologic disturbances, extrinsic asthma caused by environmental factors, essential asthma of unknown or inapparent cause, bronchitic asthma, emphysematous asthma, exercise-induced asthma, exertion asthma, allergen-induced asthma, cold air induced asthma, occupational asthma, infective asthma caused by bacterial, fungal, protozoal, or viral infection, non-allergic asthma, incipient asthma, wheezy infant syndrome, and bronchiolytis.

[00054] Included in the use of the compounds of any exemplary embodiment of formula (I) for the treatment of asthma, may be palliative treatment for the symptoms and conditions of asthma such as wheezing, coughing, shortness of breath, tightness in the chest, shallow or fast breathing, nasal flaring (nostril size increases with breathing), retractions (neck area and between or below the ribs moves inward with breathing),

cyanosis (gray or bluish tint to skin, beginning around the mouth), runny or stuffy nose, and headache.

[00055] The exemplary embodiments may also be directed to any of the uses, methods, or compositions as defined above wherein the compound of any exemplary embodiment of formula (I), or a pharmaceutically acceptable salt, hydrate, or solvate thereof, may be used in combination with another pharmacologically active compound. Specific combinations useful for the treatment of allergy or asthma may include combinations comprising a compound of formula (I), or a pharmaceutically acceptable salt, hydrate, or solvate thereof, and (i) a glucocorticosteroid or DAGR (dissociated agonist of the corticoid receptor); (ii) a β ₂ agonist, an example of which is a long-acting β ₂ agonist; (iii) a muscarinic M3 receptor antagonist or anticholinergic agent; (iv) a histamine receptor antagonist or inverse agonist, which may be an H 1 or an H3 antagonist or inverse agonist; (v) a 5-lipoxygenase inhibitor; (vi) a thromboxane inhibitor; (vii) an LTD ₄ inhibitor; (viii) a kinase inhibitor; or (ix) a vaccine. Generally, the compounds of the combination may be administered together as a formulation in association with one or more pharmaceutically acceptable excipients.

[00056] Other diseases and conditions that may be mediated, at least in part, by agonism of an EP receptor are influenza, bone fracture healing, bone disease, glaucoma, ocular hypertension, dysmenorrhoea, pre-term labor, immune disorders, osteoporosis, asthma, allergy, fertility, male sexual dysfunction, female sexual dysfunction, periodontal disease, gastric ulcer, and renal disease. EP receptor agonists may also be useful for expansion of hematopoietic stem cell populations.

[00057] Besides being useful for human treatment, compounds of formula (I) may also be useful for veterinary treatment of companion animals, exotic animals, and farm animals.

[00058] When used in the present application, the following abbreviations have the meaning set out below: Ac is acetyl; ACN is acetonitrile; BBr ₃ is boron tribromide; Bn is benzyl; BnNH ₂ is benzylamine; BSA is bovine serum albumin; CH ₂ CI ₂ is dichloromethane; CHCI ₃ is chloroform; CDCI ₃ is deuterochloroform; DCC is N ₁ N'-

dicyclohexylcarbodiimide; DME is 1 ,2-dimethoxyethane; DMF is N ₁ N- dimethylformamide; DMSO is dimethyl sulfoxide; DBU is 1 ,8- diazabicyclo[5.4.0]undec-7-ene; EDC/EDAC is λ/-(3-dimethylaminopropyl)-λ/'- ethylcarbodiimide hydrochloride; EDTA is ethylenediaminetetraacetic acid; EIA is enzyme immunoassay; Et is ethyl; Et ₃ N is triethylamine; HOBt is 1- hydroxybenzotriazole; Me is methyl; NMP is 1-methyl-2-pyrrolidinone; Ph is phenyl; Pd(PPh ₃ ) ₄ is tefr"a/c/s(triphenylphosphine)palladium; PhB(OH) ₂ is benzeneboronic acid, also known as phenylboronic acid; PhMe is toluene; rt is room temperature; t-Bu is terf-butyl; THF is tetrahydrofuran; and Tris-HCI is 2-amino-2-(hydroxymethyl)-1 ,3-propanediol hydrochloride. [00059] Unless otherwise defined herein, scientific and technical terms used in connection with the exemplary embodiments shall have the meanings that are commonly understood by those of ordinary skill in the art. [00060] Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. Generally, nomenclature used in connection with, and techniques of chemistry and molecular biology described herein are those well known and commonly used in the art.

[00061] The phrase "therapeutically effective" is intended to qualify the amount of compound or pharmaceutical composition, or the combined amount of active ingredients in the case of combination therapy. This amount or combined amount may achieve the goal of treating the relevant condition. [00062] The term "treatment," as used herein to describe the exemplary embodiments and unless otherwise qualified, means administration of the compound, pharmaceutical composition, or combination to effect preventative, palliative, supportive, restorative, or curative treatment. The term treatment encompasses any objective or subjective improvement in a subject with respect to a relevant condition or disease.

[00063] The term "preventative treatment," as used herein to describe the exemplary embodiments, means that the compound, pharmaceutical composition, or combination may be administered to a subject to inhibit or stop the relevant condition from occurring in a subject, particularly in a subject or member of a population that may be significantly predisposed to the relevant condition.

[00064] The term "palliative treatment," as used herein to describe the exemplary embodiments, means that the compound, pharmaceutical composition, or combination may be administered to a subject to remedy signs and/or symptoms of a condition, without necessarily modifying the progression of, or underlying etiology of, the relevant condition. [00065] The term "supportive treatment," as used herein to describe the exemplary embodiments, means that the compound, pharmaceutical composition, or combination may be administered to a subject as part of a regimen of therapy, but that such therapy is not limited to administration of the compound, pharmaceutical composition, or combination. Unless otherwise expressly stated, supportive treatment may embrace preventative, palliative, restorative, or curative treatment, particularly when the compounds or pharmaceutical compositions are combined with another component of supportive therapy.

[00066] The term "restorative treatment," as used herein to describe the exemplary embodiments, means that the compound, pharmaceutical composition, or combination may be administered to a subject to modify the underlying progression or etiology of a condition. Non-limiting examples include an increase in forced expiratory volume in one second (FEV 1) for lung disorders, inhibition of progressive nerve destruction, reduction of biomarkers associated and correlated with diseases or disorders, a reduction in relapses, improvement in quality of life, and the like. [00067] The term "curative treatment," as used herein to describe the exemplary embodiments, means that the compound, pharmaceutical composition, or combination may be administered to a subject for the purpose of bringing the disease or disorder into complete remission, or that the disease or disorder in undetectable after such treatment. [00068] The term "alkyl," alone or in combination, means an acyclic radical, linear or branched, preferably containing from 1 to about 6 carbon atoms. Examples of such radicals include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, /so-amyl, hexyl, heptyl, octyl, and the like. Where no specific substitution is specified, alkyl radicals may be optionally substituted with groups consisting of hydroxy, sulfhydryl, methoxy, ethoxy, amino, cyano, chloro, and fluoro.

[00069] The carbon atom content of various hydrocarbon-containing moieties is indicated by a prefix designating a lower and upper number of carbon atoms in the moiety, that is, the prefix C,-C _y indicates a moiety of the integer "i" to the integer "j" carbon atoms, inclusive. Thus, for example, '(Cr C ₈ )-alkyl' refers to alkyl of one to eight carbon atoms, inclusive. [00070] The terms "hydroxy" and "hydroxyl," as used herein, mean an OH radical.

[00071] The term "sulfhydryl," as used herein, means an SH radical. [00072] The term "oxo" means a doubly bonded oxygen. [00073] The term "alkoxy" means a radical comprising an alkyl radical that is bonded to an oxygen atom, such as a methoxy radical. [00074] The term "aryl" means a fully unsaturated mono-or multi-ring cycloalkyl having a cyclic array of p-orbitals containing 4n+2 electrons, including, but not limited to, substituted or unsubstituted phenyl, naphthyl, or anthracenyl optionally fused to a carbocyclic radical wherein aryl may be optionally substituted with one or more substituents from the group consisting of halo, methoxy, ethoxy, (CrC ₆ )-alkyl, phenyl, O-phenyl, cyano, nitro, hydroxyl, sulfhydryl, or trifluoromethyl.

[00075] The term "halo," as used herein, means one of the following group consisting of fluoro, chloro, bromo, or iodo.

[00076] The terms "heterocycle", "heterocyclic ring system," and "heterocyclyl" refer to a saturated or unsaturated mono- or multi-ring cycloalkyl wherein one or more carbon atoms is replaced by N, S, or O. The terms "heterocycle", "heterocyclic ring system," and "heterocyclyl" include fully saturated ring structures such as piperazinyl, dioxanyl, tetrahydrofuranyl, oxiranyl, aziridinyl, morpholinyl, pyrrolidinyl, piperidinyl, thiazolidinyl, and others. The terms "heterocycle", "heterocyclic ring system," and "heterocyclyl" also include partially unsaturated ring structures such as dihydrofuranyl, pyrazolinyl, imidazolinyl, pyrrolinyl, chromanyl, dihydrothiphenyl, and others. [00077] The term "heteroaryl" refers to an aromatic heterocyclic group. Heteroaryl is preferably: (a) a five-membered aromatic heterocyclic group containing either (i) 1-4 nitrogen atoms or (ii) 0-3 nitrogen atoms and 1 oxygen or 1 sulfur atom; (b) a six-membered aromatic heterocyclic group containing 1-3 nitrogen atoms; (c) a nine-membered bicyclic heterocyclic group

containing either (i) 1-5 nitrogen atoms or (ii) 0-4 nitrogen atoms and 1 oxygen or 1 sulfur atom; or (d) a ten-membered bicyclic aromatic heterocyclic group containing 1-6 nitrogen atoms; each of said groups (a)-(d) being optionally substituted by one or more of (Ci-C ₆ )-alkyl, (C _r C ₆ )-fluoroalkyl, (C ₃ -C ₆ )- cycloalkyl, hydroxy(C ₃ -C ₆ )-cycloalkyl, (C ₂ -C ₆ )-alkenyl, (C ₂ -C ₆ )-alkynyl, halo, oxo, hydroxyl, (C-ι-C ₆ )-alkoxy, sulfhydryl, -SMe, or cyano. Examples of "heteroaryl" include pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, thionyl, furanyl, pyrrolyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl, oxadiazolyl, thiadiazolyl, and tetrazolyl, optionally substituted as specified above.

[00078] In "heterocycle" or "heteroaryl," the point of attachment to the molecule of interest may be at a heteroatom or elsewhere within the ring. [00079] The term "cycloalkyl" means a mono- or multi-ringed cycloalkyl wherein each ring contains three to ten carbon atoms, preferably three to six carbon atoms. "Cycloalkyl" is preferably a monocyclic cycloalkyl containing from three to six carbon atoms. Examples include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[00080] The term "excipient" is used herein to describe any ingredient other than a compound of formula (I). The choice of excipient will to a large extent depend on factors such as the particular mode of administration, the effect of the excipient on solubility and stability, and the nature of the dosage form. The term "excipient" encompasses diluents, carrier, or adjuvant. [00081] Pharmaceutically acceptable salts of the compounds of formula (I) include the acid addition and base salts thereof.

[00082] Suitable acid addition salts are formed by acids which form nontoxic salts. Examples include the acetate, adipate, aspartate, benzoate, besylate, bicarbonate/carbonate, bisulfate/sulfate, borate, camsylate, citrate, cyclamate, edisylate, esylate, formate, fumarate, gluceptate, gluconate, glucuronate, hexafluorophosphate, hibenzate, hydrochloride/chloride, hydrobromide/bromide, hydroiodide/iodide, isethionate, lactate, malate, maleate, malonate, mesylate, methyisulfate, naphthylate, 2-napsylate, nicotinate, nitrate, orotate, oxalate, palmitate, pamoate, phosphate/hydrogen phosphate/dihydrogen phosphate, propionate, pyroglutamate, saccharate,

stearate, succinate, tannate, tartrate, tosylate, trifluoroacetate, naphthalene- 1 ,5-disulfonic acid, and xinofoate salts.

[00083] Suitable base salts are formed from bases which form non-toxic salts. Examples include the aluminum, arginine, benzathine, calcium, choline, diethylamine, diolamine, glycine, lysine, magnesium, meglumine, olamine, potassium, sodium, tromethamine, and zinc salts.

[00084] Hemisalts of acids and bases may also be formed, for example, hemisulfate and hemicalcium salts. For a review on suitable salts, see Handbook of Pharmaceutical Salts: Properties, Selection, and Use, by Stahl and Wermuth (Wiley-VCH, 2002).

[00085] The compounds of any exemplary embodiment of formula (I) may also exist in unsolvated and solvated forms. The term "solvate" is used herein to describe a molecular complex comprising the compound of any exemplary embodiment of formula (I), or a pharmaceutically acceptable salt thereof, and one or more pharmaceutically acceptable solvent molecules, for example, ethanol. The term "hydrate" is employed when said solvent is water. [00086] Also included herein are multi-component complexes other than salts and solvates wherein the compound of formula (I) and at least one other component are present in stoichiometric or non-stoichiometric amounts. [00087] The compounds of any exemplary embodiment of formula (I) may exist in a continuum of solid states ranging from fully amorphous to fully crystalline.

[00088] The compounds of any exemplary embodiment of formula (I) may also exist in a mesomorphic state (mesophase or liquid crystal) when subjected to suitable conditions. The mesomorphic state is intermediate between the true crystalline state and the true liquid state (either melt or solution).

[00089] Hereinafter all references to compounds of any exemplary embodiment of formula (I) include references to salts, solvates, multi- component complexes, and liquid crystals thereof and to solvates, multi- component complexes, and liquid crystals of salts thereof. [00090] Also included herein are all polymorphs and crystal habits of compounds of any exemplary embodiment of formula (I), prodrugs, and

isomers thereof (including optical, geometric, and tautomeric isomers) and isotopically-labeled forms thereof.

[00091] Compounds of any exemplary embodiment of formula (I) may be administered orally, topically, transdermal^, intranasally, by inhalation, directly into the bloodstream, into muscle, into an internal organ, into the eye, into the ear, into the rectum, or by other means.

[00092] The compounds herein, their methods or preparation and their biological activity will appear more clearly from the examination of the following examples that are presented as an illustration only and are not to be considered as limiting the invention in its scope. Compounds herein are identified, for example, by the following analytical methods.

[00093] Mass spectra (MS) methods include positive electrospray ionization (ESI ⁺ ), negative electrospray ionization (ESI ^" ), positive atmospheric pressure chemical ionization (APCI ⁺ ), or negative atmospheric pressure chemical ionization (APCI ^" ).

[00094] 300 MHz proton nuclear magnetic resonance spectra ( ¹ H NMR) are recorded at ambient temperature using a Bruker (300 MHz) spectrometer.

In the ¹ H NMR chemical shifts (δ) are indicated in parts per million (ppm) with reference to tetramethylsilane (TMS) as the internal standard.

[00095] The above description of embodiments of the invention is merely exemplary in nature and, thus, variations thereof are not to be regarded as a departure from the spirit and scope of the invention.

EXAMPLES

Example 1 - Preparation of Z)-7-((1R,2R)-2-((E)-3-hvdroxy-3-methyloct-1- enyl)-3-methyl-5-oxocvclopent-3-enyl)hept-5-enoic acid

Step A: Preparation of (3aR,4R,5R,6aS)-2-oxo-4-((E)-3-oxooct-1- enyl)hexahvdro-2H-cvclopenta[b1furan-5-yl benzoate

[00096] A reactor equipped with a mechanical stirrer, under nitrogen, was charged with (3aR,4R,5R,6aS)-4-formyl-2-oxohexahydro-2H- cyclopenta[b]furan-5-yl benzoate (99.2g, 0.362mol) in methylene chloride and lithium chloride (1 mol eq.) dissolved in THF. Dimethyl 2- oxoheptylphosphonate (1 mol eq.) was added neat and rinsed with methylene chloride. Some lithium chloride crystallized out of solution when the THF and methylene chloride solutions were mixed. The mixture was stirred under nitrogen and cooled to -20 ⁰ C. Upon adding the phosphonate and further stirring and cooling, the lithium chloride had dissolved. After stirring for 2.5h, triethylamine (1 mol eq.) was added neat via addition funnel and the temperature was held at -5 ⁰ C and stirred at this temperature for 19h. The temperature was adjusted to 0 ⁰ C and treated with 5% aqueous citric acid and the layers were separated. The organic layer was dried over magnesium sulfate and filtered. The crude product was purified on silica gel, eluted with ethyl acetate: hexanes (1 :1) to give (3aR,4R,5R,6aS)-2-oxo-4-((E)-3-oxooct- 1-enyl)hexahydro-2H-cyclopenta[b]furan-5-yl benzoate.

Step B: Preparation of (3aR.4R,5R,6aS)-4-((E)-3-hydroxy-3-methyloct- 1 -enyl)-2-oxohexahvdro-2H-cvclopenta[b1furan-5-yl benzoate

[00097] (3aR,4R,5R,6aS)-2-oxo-4-((E)-3-oxooct-1-enyl)hexahydro-2H- cyclopenta[b]furan-5-yl benzoate (1 molar equivalent) was dissolved in THF (0.1 M) under nitrogen atmosphere. The solution was cooled to -78 ⁰ C and methyl magnesium bromide (1 molar equivalent, 1 M solution in THF) was added drop-wise. The reaction mixture was stireed at -78 ⁰ C until reaction progress stopped. Upon completion, brine was added to the crude reaction mixture and the product was extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered, and evaporated. The product was purified by flash chromatography on regular silica gel, eluted with ethyl acetate: hexanes to give (3aR,4R,5R,6aS)-4-((E)-3-hydroxy-3- methyloct-i-enyO-Z-oxohexahydro^H-cyclopentatbJfuran-δ-yl benzoate,.

Step C: Preparation of (3aR,4R,5R,6aS)-4-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-2-oxohexahydro-2H - cyclopentarbifuran-5-yl benzoate

[00098] (3aR,4R,5R,6aS)-4-((E)-3-hydroxy-3-methyloct-1-enyl)-2- oxohexahydro-2H-cyclopenta[b]furan-5-yl benzoate (1 mol eq.) was dissolved in DMF (5M) and imidazole (1.1 mol eq.) as added. The mixture was cooled to 0 ⁰ C under nitrogen atmosphere and a solution of TBDPSCI (1.1 mol eq.) dissolved in DMF was added slowly. Upon completion of the reaction, as judged by TLC, the reaction mixture was diluted with ethyl acetate, washed with water and brine. The organic layer was dried over sodium sulfate, filtered and evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (3aR,4R,5R,6aS)- 4-((E)-3-(tert-butyldiphenylsilyloxy)-3-methyloct-1-enyl)-2- oxohexahydro-2H- cyclopenta[b]furan-5-yl benzoate.

Step D: Preparation of (3aR,4R,5R,6aS)-4-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-5-hvdroxyhexahvdr o- 2H-cyclopenta[b1furaπ-2-one

[00099] (3aR,4R,5R,6aS)-4-((E)-3-(tert-butyldiphenylsilyloxy)-3- methyloct-1 -enyl)-2-oxohexahydro-2H-cyclopeπta[b]furan-5-yI benzoate (1 mol eq.) was dissolved in methanol (0.2M) and potassium carbonate (o.6 mol eq.) was added. The reaction was stirred at room temperature and the progress was monitored by TLC every 30 minutes. After complete consumption of starting material, the reaction mixture was acidified with 5% KHSO ₄ and diluted with brine. The product was extracted with ethyl acetate twice. The combined organic layers were dried over sodium sulfate, filtered and evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes (1 :1) to give (3aR,4R,5R,6aS)-4-((E)-3-(tert-butyldiphenylsilyloxy)-3-meth yloct-1-enyl)-5- hydroxyhexahydro-2H-cyclopenta[b]furan-2-one.

Step E: Preparation of (3aR,4R,5R,6aS)-4-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-5-(tetrahvdro-2H- pyran-2-yloxy)hexahvdro-2H-cvclopentarb1furan-2-one

[000100] (3aR,4R,5R,6aS)-4-((E)-3-(tert-butyidiphenylsilyloxy)-3- methyloct-1-enyl)-5-hydroxyhexahydro-2H-cycIopenta[b]furan-2 -one was dissolved in methylene chloride (0.1 M) under nitrogen atmosphere. Dihydropyran (1.1 mol eq.) was added, followed by a catalytic amount of p- toluenesulfonic acid. The reaction was stirred at room temperature under nitrogen atmosphere and the reaction progress was monitored by TLC. Upon completion, brine was added to the reaction mixture and the layers were separated. The organic phase was dried over sodium sulfate, filtered, and the solvent was evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (3aR,4R,5R,6aS)-4-((E)-3-(tert-butyldiphenylsilyloxy)-3-meth yloct-1- enyl)-5-(tetrahydro-2H-pyran-2-yloxy)hexahydro-2H-cyclopenta [b]furan-2-one.

Step F: Preparation of (3aR,4R,5R,6aS)-4-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-5-(tetrahvdro-2H- PVran-2-yloxy)hexahvdro-2H-cyclopenta[b1furan-2-ol

[000101] (3aR,4R,5R,6aS)-4-((E)-3-(tert-butyldiphenylsilyloxy)-3- methyloct-1-enyl)-5-(tetrahydro-2H-pyran-2-yloxy)hexahydro-2 H- cyclopenta[b]furan-2-one (1 mol eq.) was dissolved in anhydrous THF (0.5M) under nitrogen atmosphere and cooled to -78 ⁰ C. A solution of DIBAL-H (2 eq, 1 M, toluene) was added to the reaction mixture drop-wise and stirred for 3 hours. Ethyle acetate (2OmL) was added and the mixture was stirred for an

additional 5 minutes. The mixture was then treated with 30% aqueous K, Na tartrate and stirred vigorously overnight. The layers were separated and the organic phase was filtered and concentrated under reduced pressure. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (3aR,4R,5R,6aS)-4-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-5-(tetrahydro-2H- pyran-2- yloxy)hexahydro-2H-cyclopenta[b]furan-2-ol.

Step G: Preparation of (Z)-7-((1 R,2R,3R,5S)-2-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-5-hvdroxy-3- (tetrahvdro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enoic acid

[000102] 4-carboxybutyltriphenylphosphonium bromide (3.5 mol eq.) was suspended in anhydrous THF under a nitrogen atmosphere. 1M potassium tert-butoxide (7 mol eq.) in THF was added drop-wise to the white suspension. The reaction mixture became bright red over the course of the addition. It was stirred for 30 minutes at room temperature then cooled to - 15°C in an ice/NaCI bath. The lactol (3aR,4R,5R,6aS)-4-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-5-(tetrahydro-2H- pyran-2- yloxy)hexahydro-2H-cyclopenta[b]furan-2-ol (1 mol eq.) was dissolved in THF and added drop-wise to the ylide. The reaction mixture became lighter orange in color. It was stirred for 2 hours at -15 ⁰ C and was then allowed to warm to room temperature and stir over-night. The reaction mixture became dark red. TLC indicated no remaining starting material. The reaction mixture was acidified with 5% KHSO ₄ , diluted with 25OmL of brine and extracted with 20OmL of ethyl acetate. The aqueous layer was extracted with another 5OmL of ethyl acetate and the combined organic extracts were washed twice with 25OmL of brine, dried over sodium sulfate and evaporated to yield 900mg of

crude product. The crude product was purified by flash chromatography on regular silica gel using ethyl acetate-hexane-acetic acid as eluent to give (Z)- 7-((1 R,2R,3R,5S)-2-((E)-3-(tert-butyldiphenylsilyloxy)-3-methyloc t-1-enyl)-5- hvdroxy-3-(tetrahvdro-2H-pyran-2-yloxy)cvclopentyl)hept-5-en oic acid.

Step H: Preparation of (Z)-methyl 7-((1 R.2R,3R,5S)-2-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-5-hvdroxy-3- (tetrahvdro-2H-pyran-2-yloxy)cvclopentyl)hept-5-enoate

[000103] (Z)-7-((1 R,2R,3R,5S)-2-((E)-3-(tert-butyldiphenylsilyloxy)-3- methyloct-1-enyl)-5-hydroxy-3-(tetrahydro-2H-pyran-2-yloxy)c yclopentyl)hept- 5-enoic acid was dissolved in ethyl ether (0.1 M) and cooled to 0 ⁰ C under nitrogen atmosphere. Diazomethane (freshly prepared solution in ethyl ether) was added to the solution, with stirring under a light yellow color persisted. The completion of the reaction was confirmed by the absence of starting material as judged by TLC. Upon completion, the solvents were evaporated and the product was purified by flash chromatography using ethyl acetate- hexane as eluent to give (Z)-methyl 7-((1 R,2R,3R,5S)-2-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-5-hydroxy-3-(tetr ahydro-2H-pyran- 2-yloxy)cyclopentyl)hept-5-enoate.

Step I: Preparation of (Z)-methyl 7-((1 R,2R,3R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3-(tert-butyldiphenylsilyloxy) -3- methyloct-1-enyl)-3-(tetrahvdro-2H-pyran-2- yloxy)cvclopentyl)hept-5-enoate

[000104] (Z)-methyl 7-((1 R,2R,3R,5S)-2-((E)-3-(tert-butyldiphenylsilyloxy)- 3-methyloct-1-enyl)-5-hydroxy-3-(tetrahydro-2H-pyran-2- yloxy)cyclopentyl)hept-5-enoate (1 mol eq.) was dissolved in DMF (5M) and imidazole (1.1 mol eq.) as added. The mixture was cooled to 0 ⁰ C under nitrogen atmosphere and a solution of TBDPSCI (1.1 mol eq.) dissolved in DMF was added slowly. Upon completion of the reaction, as judged by TLC, the reaction mixture was diluted with ethyl acetate, washed with water and brine. The organic layer was dried over sodium sulfate, filtered and evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (Z)-methyl 7- ((1 R,2R,3R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-3-(tetrahydro-2H- pyran-2- yloxy)cyclopentyl)hept-5-enoate.

Step J: Preparation of (Z)-methyl 7-((1 R,2R,3R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3-(tert-butyldiphenylsilyloxy) -3- methyloct-i-envπ-S-hvdroxycvclopentvDhept-δ-enoate

[000105] (Z)-methyl 7-((1 R,2R,3R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)- 3-(tert-butyldiphenylsilyloxy)-3-methyloct-1-enyl)-3-(tetrah ydro-2H-pyran-2- yloxy)cyclopentyl)hept-5-enoate was dissolved in a (4:2:1) solution of acetic acid:water:THF (0.5M). The solution was stirred for several days at room temperature until the reaction was complete, as judged by TLC. The crude

product was purified by flash chromatography on regular silica gel using ethyl acetate-hexane-acetic acid as eluent to give (Z)-methyl 7-((1 R,2R,3R,5S)-5- (tert-butyldiphenylsilyloxy)-2-((E)-3-(tert-butyldiphenylsil yloxy)-3-methyloct-1- enyl)-3-hydroxycyclopentyl)hept-5-enoate.

Step K: Preparation of (Z)-methyl 7-((1 R,2R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3-(tert-butyldiphenylsilyloxy) -3- methyloct-i-envD-S-oxocvclopentvDhept-δ-enoate

[000106] (Z)-methyl 7-((1 R,2R,3R,5S)-5-(tert-butyldiphenylsiIyloxy)-2-((E)- 3-(tert-butyldiphenylsilyloxy)-3-methyloct-1-enyl)-3-hydroxy cycIopentyl)hept-5- enoate was dissolved in acetone (0.1 M) and cooled to -25 ⁰ C. Jones reagent (1 mol eq.) was added dropwise with stirring. Upon completion, as judged by TLC, the reaction was quenched with isopropyl alcohol and the crude reaction mixture was diluted with ethyl acetate, washed three times with brine, and dried over magnesium sulfate. After filtration and solvent evaporationthe the product was purified by flash chromatography using ethyl acetate-hexane as eluent to give (Z)-methyl 7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)-3- (tert-butyldiphenylsilyloxy)-3-methyloct-1-enyl)-3-oxocyclop entyl)hept-5- enoate.

Step L: Preparation of (Z)-methyl 7-((1 R,2R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3-(tert-butyldiphenylsilyloxy) -3- methyloct-i-envD-S-methylenecvclopentvDhept-δ-enoate

[000107] (Z)-methyl 7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)-3- (tert-butyldiphenylsilyloxy)-3-methyloct-1-enyl)-3-oxocyclop entyl)hept-5- enoate (1 mol eq.) was dissolved in methylene chloride (0.05M) under nitrogen atmosphere and cooled to 0 ⁰ C. A solution of zinc methylenedibromide titanium tetrachloride was prepared by combining 2.3g of zinc dust in 40 mL of THF with 0.81 mL of methylene dibromide at -40 ⁰ C under nitrogen atmosphere. To the suspension was added 0.92 mL of TiCI ₄ , slowly. 2 mL portions of the solution of zinc methylenedibromide titanium tetrachloride were added until the reaction was complete as judged by TLC. Upon completion, the reaction mixture was diluted with ethyl acetate and filtered twice through a bed of celite. The filtrate was washed with a saturated aqueous solution of sodium bicarbonate, then with a 50% aqueous solution of brine. The organic phase was dried over sodium sulfate, filtered, and the solvent was evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (Z)-methyl 7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-3-methylenecyclop entyl)hept-5- enoate.

Step M: Preparation of (Z)-7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)- 2-((E)-3-(tert-butyldiphenylsilyloxy)-3-methyloct-1-enyl)-3- methylenecvclopentyl)hept-5-enoic acid

[000108] (Z)-methyl 7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)-3- (tert-butyldiphenylsilyloxy)-3-methyloct-1 -enyl)-3-methylenecyclopentyl)hept- 5-enoate (1 mol eq.) was dissolved in a 3:1 solution of methanol and 1 N LiOH (0.01 M) and stirred at 4 ⁰ C. Upon completion of the reaction, as judged by TLC, the reaction mixture was diluted with ethyl acetate, washed with 5% KHSO ₄ and brine. The organic phase was dried over sodium sulfate, filtered, and the solvent was evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (Z)-7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-3-methylenecyclop entyl)hept-5- enoic acid.

Step N: Preparation of (Z)-7-((1 R,2R,5S)-5-hydroxy-2-((E)-3-hydroxy-3- methyloct-1 -envD-S-methylenecvclopentvDhept-δ-enoic acid

[000109] (Z)-7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2~((E)-3-(tert- butyldiphenylsilyloxy)-3-methyloct-1-enyl)-3-methylenecyclop entyl)hept-5- enoic acid (1 mol eq.) was dissolved in THF (0.3M) under nitrogen atmosphere. A solution of TBAF (1.2 mol eq.; 1 M, THF) was added and the reaction mixture was stirred at room temperature. Upon completion, as judged by TLC, water was added and most of the THF was removed under reduced pressure. The remaining aqueous solution was extracted with ethyl acetate, washed with water and brine. The organic phase was dried over sodium sulfate, filtered, and the solvent was evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes (+ 0.4% acetic acid) to give (Z)-7-((1 R,2R,5S)-5-hydroxy-2- ((E)-3-hydroxy-3-methyloct-1-enyl)-3-methylenecyclopentyl)he pt-5-enoic acid.

Step O: Preparation of (Z)-7-((1 R.2R)-2-((E)-3-hydroxy-3-methyloct-1- envD-S-methyl-δ-oxocyclopent-S-envDhept-δ-enoic acid

[000110] (Z)-7-((1 R,2R,5S)-5-hydroxy-2-((E)-3-hydroxy-3-methyloct-1- enyl)-3-methylenecyclopentyl)hept-5-enoic acid was dissolved in acetone (0.1M) and cooled to -25 ⁰ C. Jones reagent (1 mol eq.) was added dropwise with stirring. Upon completion, as judged by TLC, the reaction was quenched with isopropyl alcohol and the crude reaction mixture was diluted with ethyl acetate, washed three times with brine, and dried over magnesium sulfate. After filtration and solvent evaporationthe the product was purified by flash chromatography using ethyl acetate-hexane as eluent to give (Z)-7-((1 R,2R)- 2-((E)-3-hydroxy-3-methyloct-1-enyl)-3-methyl-5-oxocyclopent -3-enyI)hept-5- enoic acid._The 15-hydroxy, 15-methyl epimers may be resolved or used as an epimeric mixture.

Example 2 (Z)-7-((1R,2R)-2-((E)-3,3-difluorooct-1-envn-3-methyl-5- oxocvclopent-3-enyl)hept-5-enoic acid

Step A: Preparation of (3aR,4R,5R,6aS)-2-oxo-4-((E)-3-oxooct-1- enyl)hexahvdro-2H-cyclopenta[b1furan-5-yl benzoate

[0001 11] A reactor equipped with a mechanical stirrer, under nitrogen, was charged with (3aR,4R,5R,6aS)-4-formyl-2-oxohexahydro-2H- cyclopenta[b]furan-5-yl benzoate (99.2g, 0.362mol) in methylene chloride and lithium chloride (1 mol eq.) dissolved in THF. Dimethyl 2- oxoheptylphosphonate (1 mol eq.) was added neat and rinsed with methylene chloride. Some lithium chloride crystallized out of solution when the THF and methylene chloride solutions were mixed. The mixture was stirred under nitrogen and cooled to -20 ⁰ C. Upon adding the phosphonate and further stirring and cooling, the lithium chloride had dissolved. After stirring for 2.5h, triethylamine (1 mol eq.) was added neat via addition funnel and the temperature was held at -5 ⁰ C and stirred at this temperature for 19h. The temperature was adjusted to 0 ⁰ C and treated with 5% aqueous citric acid and the layers were separated. The organic layer was dried over magnesium sulfate and filtered. The crude product was purified on silica gel, eluted with ethyl acetate: hexanes (1 : 1) to give (3aR,4R,5R,6aS)-2-oxo-4-((E)-3-oxooct- 1-enyl)hexahydro-2H-cyclopenta[b]furan-5-yl benzoate.

Step B: Preparation of (3aR,4R,5R.6aS)-4-((E)-3,3-difluorooct-1-enyl)- 2-oxohexahvdro-2H-cyclopentafb1furan-5-vl benzoate

[0001 12] (3aR,4R,5R,6aS)-2-oxo-4-((E)-3-oxooct-1-enyl)hexahydro-2H- cyclopenta[b]furan-5-yl benzoate (1 molar equivalent) is dissolved in anhydrous methylene chloride (0.5M) and cooled to 0 ⁰ C under nitrogen atmosphere. A catalytic amount of ethanol (25 mol%) is added followed by the slow addition of DAST (5 mol eq.). The reaction mixture is allowed to slowly warm to room temperature overnight. Stirring is continued for several days until the reaction is complete as judged by TLC. Upon completion the reaction is cooled to 0 ⁰ C and quenched by the slow addition of a saturated solution of sodium bicarbonate. The layers are separated and the aqueous phase is extracted with ethyl acetate. The organic layers are combined and dried over magnesium sulfate. The solvents are evaporated and the crude material is purified on regular silica gel eluted with ethyl acetate: hexanes solvent system to give (3aR,4R,5R,6aS)-4-((E)-3,3-difluorooct-1-enyl)-2- oxohexahydro-2H-cyclopenta[b]furan-5-yl benzoate.

Step C: Preparation of (3aR,4R,5R,6aS)-4-((E)-3,3-difluorooct-1-enyl)- 5-hvdroxyhexahvdro-2H-cvclopenta[b1furan-2-one

[0001 13] (3aR,4R,5R,6aS)-4-((E)-3,3-difluorooct-1-enyl)-2-oxohexahydr o- 2H-cyclopenta[b]furan-5-yl benzoate (1 mol eq.) was dissolved in methanol (0.2M) and potassium carbonate (o.6 mol eq.) was added. The reaction was stirred at room temperature and the progress was monitored by TLC every 30 minutes. After complete consumption of starting material, the reaction mixture was acidified with 5% KHSO ₄ and diluted with brine. The product was

extracted with ethyl acetate twice. The combined organic layers were dried over sodium sulfate, filtered and evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes (1 :1) to give (3aR,4R,5R,6aS)-4-((E)-3,3-difluorooct-1-enyl)-5- hydroxyhexahydro-2H-cyclopenta[b]furan-2-one.

Step D: Preparation of (3aR,4R,5R,6aS)-4-((E)-3,3-difluorooct-1-enyl)- 5-(tetrahvdro-2H-pyran-2-yloxy)hexahvdro-2H- cyclopenta[blfuran-2-one

[000114] (3aR,4R,5R,6aS)-4-((E)-3,3-difluorooct-1-enyl)-5- hydroxyhexahydro-2H-cyclopenta[b]furan-2-one was dissolved in methylene chloride (0.1 M) under nitrogen atmosphere. Dihydropyran (1.1 mol eq.) was added, followed by a catalytic amount of p-toluenesulfonic acid. The reaction was stirred at room temperature under nitrogen atmosphere and the reaction progress was monitored by TLC. Upon completion, brine was added to the reaction mixture and the layers were separated. The organic phase was dried over sodium sulfate, filtered, and the solvent was evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (3aR,4R,5R,6aS)-4-((E)-3,3-difluorooct-1-envD- 5-(tetrahvdro-2H-pyran-2-yloxy)hexahvdro-2H-cvclopenta[b1fur an-2-one.

Step E: Preparation of (3aR,4R,5R,6aS)-4-((E)-3.3-difluorooct-1-enyl)- 5-(tetrahvdro-2H-pyran-2-yloxy)hexahvdro-2H- cyclopentafblfuran-2-ol

[000115] (3aR,4R,5R,6aS)-4-((E)-3,3-difluorooct-1-enyl)-5-(tetrahydro - 2H-pyran-2-yloxy)hexahydro-2H-cyclopenta[b]furan-2-one (1 mol eq.) was dissolved in anhydrous THF (0.5M) under nitrogen atmosphere and cooled to -78 ⁰ C. A solution of DIBAL-H (2 eq, 1 M, toluene) was added to the reaction mixture drop-wise and stirred for 3 hours. Ethyle acetate (2OmL) was added and the mixture was stirred for an additional 5 minutes. The mixture was then treated with 30% aqueous K, Na tartrate and stirred vigorously overnight. The layers were separated and the organic phase was filtered and concentrated under reduced pressure. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (3aR,4R,5R,6aS)-4-((E)-3,3-difluorooct-1-enyl)-5-(tetrahydro -2H-pyran-2- yloxy)hexahydro-2H-cyclopenta[b]furan-2-ol.

Step F: (Z)-7-((1 R,2R,3R,5S)-2-((E)-3,3-difluorooct-1-enyl)-5-hvdroxy- 3-(tetrahvdro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enoic acid

[000116] 4-carboxybutyltriphenylphosphonium bromide (3.5 mol eq.) was suspended in anhydrous THF under a nitrogen atmosphere. 1M potassium tert-butoxide (7 mol eq.) in THF was added drop-wise to the white suspension. The reaction mixture became bright red over the course of the addition. It was stirred for 30 minutes at room temperature then cooled to - 15°C in an ice/NaCI bath. The lactol (3aR,4R,5R,6aS)-4-((E)-3,3-difluorooct-

1-enyl)-5-(tetrahydro-2H-pyran-2-yloxy)hexahydro-2H-cyclopen ta[b]furan-2-ol (1 mol eq.) was dissolved in THF and added drop-wise to the ylide. The reaction mixture became lighter orange in color. It was stirred for 2 hours at - 15°C and was then allowed to warm to room temperature and stir over-night. The reaction mixture became dark red. TLC indicated no remaining starting material. The reaction mixture was acidified with 5% KHSO ₄ , diluted with 25OmL of brine and extracted with 20OmL of ethyl acetate. The aqueous layer was extracted with another 5OmL of ethyl acetate and the combined organic extracts were washed twice with 25OmL of brine, dried over sodium sulfate and evaporated to yield 900mg of crude product. The crude product was purified by flash chromatography on regular silica gel using ethyl acetate- hexane-acetic acid as eluent to give (Z)-7-((1 R,2R,3R,5S)-2-((E)-3,3- difluorooct-1-enyl)-5-hydroxy-3-(tetrahydro-2H-pyran-2- yloxy)cyclopentyl)hept-5-enoic acid.

Step G: Preparation of (Z)-methyl 7-((1 R,2R,3R,5S)-2-((E)-3,3- difluorooct-1-enyl)-5-hvdroxy-3-(tetrahvdro-2H-pyran-2- yloxy)cvclopentyl)hept-5-enoate

[000117] (Z)-7-((1 R,2R,3R,5S)-2-((E)-3,3-difluorooct-1-enyl)-5-hydroxy-3- (tetrahydro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enoic acid was dissolved in ethyl ether (0.1 M) and cooled to 0 ⁰ C under nitrogen atmosphere. Diazomethane (freshly prepared solution in ethyl ether) was added to the solution, with stirring under a light yellow color persisted. The completion of the reaction was confirmed by the absence of starting material as judged by TLC. Upon completion, the solvents were evaporated and the product was purified by flash chromatography using ethyl acetate-hexane as eluent to give (Z)-methyl 7-((1 R,2R,3R,5S)-2-((E)-3,3-difluorooct-1-enyl)-5-hydroxy-3- (tetrahydro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enoate.

Step H: Preparation of (Z)-methyl 7-((1 R,2R,3R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3,3-difluorooct-1-enyl)-3- (tetrahvdro-2H-pyran-2-yloxy)cvclopentyl)hept-5-enoate

[000118] (Z)-methyl 7-((1 R,2R,3R,5S)-2-((E)-3,3-difluorooct-1-enyl)-5- hydroxy-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)hept-5-en oate (1 mol eq.) was dissolved in DMF (5M) and imidazole (1.1 mol eq.) as added. The mixture was cooled to 0 ⁰ C under nitrogen atmosphere and a solution of TBDPSCI (1.1 mol eq.) dissolved in DMF was added slowly. Upon completion of the reaction, as judged by TLC, the reaction mixture was diluted with ethyl acetate, washed with water and brine. The organic layer was dried over sodium sulfate, filtered and evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (Z)-methyl 7-((1 R,2R,3R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)-3,3- difluorooct-1-enyl)-3-(tetrahydro-2H-pyran-2-yloxy)cyclopent yl)hept-5-enoate.

Step I: Preparation of (Z)-methyl 7-((1 R,2R,3R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3,3-difluorooct-1-enyl)-3- hvdroxycyclopentyl)hept-5-enoate

[0001 19] (Z)-methyl 7-((1 R,2R,3R,5S)-5-(tert-butyldiphenylsiIyloxy)-2-((E)- 3,3-difluorooct-1-enyl)-3-(tetrahydro-2H-pyran-2-yloxy)cyclo pentyl)hept-5- enoate was dissolved in a (4:2:1) solution of acetic acid:water:THF (0.5M).

The solution was stirred for several days at room temperature until the reaction was complete, as judged by TLC. The crude product was purified by flash chromatography on regular silica gel using ethyl acetate-hexane-acetic acid as eluent to give (Z)-methyl 7-((1 R,2R,3R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3,3-difluorooct-1-enyl)-3- hydroxycyclopentyl)hept-5-enoate.

Step J: Preparation of (Z)-methyl 7-((1 R,2R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3,3-difluorooct-1-enyl)-3- oxocvclopentyl)hept-5-enoate

[000120] (Z)-methyl 7-((1 R,2R,3R,5S)-5-(tert-butyldiphenylsiIyloxy)-2-((E)- S.S-difluorooct-i-enyO-S-hydroxycyclopenty^hept-δ-enoate was dissolved in acetone (0.1 M) and cooled to -25 ⁰ C. Jones reagent (1 mol eq.) was added dropwise with stirring. Upon completion, as judged by TLC, the reaction was quenched with isopropyl alcohol and the crude reaction mixture was diluted with ethyl acetate, washed three times with brine, and dried over magnesium sulfate. After filtration and solvent evaporationthe the product was purified by flash chromatography using ethyl acetate-hexane as eluent to give (Z)-methyl 7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)-3,3-difluoroo ct-1-enyl)-3- oxocyclopentyl)hept-5-enoate.

Step K: Preparation of (Z)-methyl 7-((1 R,2R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3,3-difluorooct-1-enyl)-3- methylenecvclopentvOhept-5-enoate

[000121] (Z)-methyl 7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)- S.S-difluorooct-i-enyO-S-oxocyclopentyOhept-δ-enoate (1 mol eq.) was dissolved in methylene chloride (0.05M) under nitrogen atmosphere and cooled to 0 ⁰ C. A solution of zinc methylenedibromide titanium tetrachloride was prepared by combining 2.3g of zinc dust in 40 ml_ of THF with 0.81 mL of methylene dibromide at -40 ⁰ C under nitrogen atmosphere. To the suspension was added 0.92 mL of TiCI ₄ , slowly. 2 mL portions of the solution of zinc methylenedibromide titanium tetrachloride were added until the reaction was complete as judged by TLC. Upon completion, the reaction mixture was diluted with ethyl acetate and filtered twice through a bed of celite. The filtrate was washed with a saturated aqueous solution of sodium bicarbonate, then with a 50% aqueous solution of brine. The organic phase was dried over sodium sulfate, filtered, and the solvent was evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (Z)-methyl 7-((1 R,2R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3,3-difluorooct-1-enyl)-3- methyIenecyclopentyl)hept-5-enoate.

Step L: Preparation of (Z)-7-((1 R,2R.5S)-5-(tert-butyldiphenylsilyloxy)- 2-((E)-3,3-difluorooct-1-enyl)-3-methylenecvclopentyl)hept-5 - enoic acid

[000122] (Z)-methyl 7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)- S.S-difluorooct-i-enyO-S-methylenecyclopentyOhept-δ-enoate (1 mol eq.) was dissolved in a 3:1 solution of methanol and 1 N LiOH (0.01 M) and stirred at 4 ⁰ C. Upon completion of the reaction, as judged by TLC, the reaction mixture was diluted with ethyl acetate, washed with 5% KHSO ₄ and brine. The organic phase was dried over sodium sulfate, filtered, and the solvent was

evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give (Z)-7-((1 R,2R,5S)- 5-(tert-butyldiphenylsilyloxy)-2-((E)-3,3-difluorooct-1 -enyl)-3- methylenecyclopentyl)hept-5-enoic acid.

Step M: Preparation of (Z)-7-((1 R.2R,5S)-2-((E)-3,3-difluorooct-1-enyl)- 5-hvdroxy-3-methylenecvclopentyl)hept-5-enoic acid

[000123] (Z)-7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)-3,3- difluorooct-1-enyl)-3-methylenecyclopentyl)hept-5-enoic acid (1 mol eq.) was dissolved in THF (0.3M) under nitrogen atmosphere. A solution of TBAF (1.2 mol eq.; 1M, THF) was added and the reaction mixture was stirred at room temperature. Upon completion, as judged by TLC, water was added and most of the THF was removed under reduced pressure. The remaining aqueous solution was extracted with ethyl acetate, washed with water and brine. The organic phase was dried over sodium sulfate, filtered, and the solvent was evaporated. The crude product was purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes (+ 0.4% acetic acid) to give fZ)-7-(f1 R.2R.5S)-2-f(E)-3.3-difluorooct-1-enyl)-5- hvdroxy-3-methylenecvclopentyl)hept-5-enoic acid.

Step N: Preparation of (Z)-7-((1 R.2R)-2-((E)-3,3-difluorooct-1-enyl)-3- methyl-5-oxocvclopent-3-env0hept-5-enoic acid

[000124] (Z)-7-((1 R,2R,5S)-2-((E)-3,3-difluorooct-1~enyl)-5-hydroxy-3- methylenecyclopentyl)hept-5-enoic acid was dissolved in acetone (0.1 M) and cooled to -25 ⁰ C. Jones reagent (1 mol eq.) was added dropwise with stirring. Upon completion, as judged by TLC, the reaction was quenched with isopropyl alcohol and the crude reaction mixture was diluted with ethyl acetate, washed three times with brine, and dried over magnesium sulfate. After filtration and solvent evapo ratio nth e the product was purified by flash chromatography using ethyl acetate-hexane as eluent to give (Z)-7-((1 R,2R)- 2-((E)-3,3-difluorooct-1-enyl)-3-methyl-5-oxocyclopent-3-eny l)hept-5-enoic acid.

Example 3 - Preparation of (Z)-7-((1R,2R,3R)-2-((E)-3,3-difluoro-4- hvdroxyoct-1-enyl)-3-hvdroxy-5-oxocvclopentyl)hept-5-enoic acid

Example 4 - Preparation of (Z)-7-((1R,2R,5S)-2-((E)-3,3-difluoro-4- hvdroxyoct-1-enyl)-5-hvdroxy-3-oxocvclopentyl)hept-5-enoic acid

Step A: Preparation of dimethyl 2-oxo-3-(tetrahvdro-2H-pyran-2- yloxy)heptylphosphonate

[000125] Methyl 2-hydroxyhexanoate (1 mol eq., available from Sinochemexper) is dissolved in methylene chloride (0.1 M) under nitrogen atmosphere. Dihydropyran (1.1 mol eq.) is added, followed by a catalytic amount of p-toluenesulfonic acid. The reaction is stirred at room temperature under nitrogen atmosphere and the reaction progress is monitored by TLC. Upon completion, brine is added to the reaction mixture and the layers are separated. The organic phase is dried over sodium sulfate, filtered, and the solvent is evaporated. The crude product is purified by flash chromatography on regular silica gel eluted with ethyl acetate: hexanes to give methyl 2- (tetrahydro-2H-pyran-2-yloxy)hexanoate. Methyl 2-(tetrahydro-2H-pyran-2- yloxy)hexanoate is converted to the title compound by treating with diethyl methyphosphonate as previously described (J.Org.Chem., 73(12), 2008, 4568-4574).

Step B: Preparation of (3aR,4R,5R,6aS)-4-((E)-4-(tert- butyldimethylsilyloxy)-3-oxooct-1-enyl)-2-oxohexahvdro-2H- cvclopenta[blfuran-5-yl benzoate

[000126] A reactor equipped with a mechanical stirrer, under nitrogen, is charged with (3aR,4R,5R,6aS)-4-formyl-2-oxohexahydro-2H- cyclopenta[b]furan-5-yl benzoate (99.2g, 0.362mol) in methylene chloride and lithium chloride (1 mol eq.) dissolved in THF. Dimethyl 2-oxo-3-(tetrahydro- 2H-pyran-2-yloxy)heptylphosphonate

[000127] (1 mol eq.) is added neat and rinsed with methylene chloride. Some lithium chloride crystallizes out of solution when the THF and methylene chloride solutions are mixed. The mixture is stirred under nitrogen and cooled to -20 ⁰ C. Upon adding the phosphonate and further stirring and cooling, the lithium chloride dissolves. After stirring for 2.5h, triethylamine (1

mol eq.) is added neat via addition funnel and the temperature is held at -5 ⁰ C and stirred at this temperature for 19h. The temperature is adjusted to 0 ⁰ C and treated with 5% aqueous citric acid and the layers are separated. The organic layer is dried over magnesium sulfate and filtered. The crude product is purified on silica gel, eluted with ethyl acetate: hexanes to give (3aR,4R,5R,6aS)-4-((E)-4-(tert-butyldimethylsilyloxy)-3-oxoo ct-1-enyl)-2- oxohexahydro-2H-cyclopenta[b]furan-5-yl benzoate.

Step C: Preparation of (3aR,4R,5R,6aS)-4-((E)-3,3-difluoro-4-

(tetrahvdro-2H-pyran-2-yloxy)oct-1-enyl)-2-oxohexahvdro-2 H- cvclopenta[b1furan-5-vl benzoate

[000128] (3aR,4R,5R,6aS)-4-((E)-4-(tert-butyldimethylsilyloxy)-3-oxoo ct- 1-enyl)-2-oxohexahydro-2H-cyclopenta[b]furan-5-yl benzoate is dissolved in anhydrous methylene chloride (0.5M) and cooled to 0 ⁰ C under nitrogen atmosphere. A catalytic amount of ethanol (25 mol%) is added followed by the slow addition of DAST (5 mol eq.). The reaction mixture is allowed to slowly warm to room temperature overnight. Stirring is continued for several days until the reaction is complete as judged by TLC. Upon completion the reaction is cooled to 0 ⁰ C and quenched by the slow addition of a saturated solution of sodium bicarbonate. The layers are separated and the aqueous phase is extracted with ethyl acetate. The organic layers are combined and dried over magnesium sulfate. The solvents are evaporated and the crude material is purified on regular silica gel eluted with ethyl acetate:hexanes solvent system to give (3aR,4R,5R,6aS)-4-((E)-3,3-difluoro-4-(tetrahydro-2H- pyran-2-yloxy)oct-1-enyl)-2-oxohexahydro-2H-cyclopenta[b]fur an-5-yl benzoate.

Step D: Preparation of (3aR,4R,5R,6aS)-4-((E)-3,3-difluoro-4-

(tetrahvdro-2H-pyran-2-yloxy)oct-1-enyl)-5-hvdroxyhexahvd ro- 2H-cyclopenta[b1furan-2-one

[000129] (3aR,4R,5R,6aS)-4-((E)-3,3-difluoro-4-(tetrahydro-2H-pyran-2 - yloxy)oct-1 -enyO-δ-hydroxyhexahydro^H-cyclopentatbJfuran^-one may be synthesized as described for example 2, step C.

Step E: Preparation of (3aR.4R,5R,6aS)-4-((E)-3,3-difluoro-4- (tetrahvdro-2H-pyran-2-yloxy)oct-1-enyl)hexahydro-2H- cyclopenta[b1furan-2,5-diol

[000130] (3aR,4R,5R,6aS)-4-((E)-3,3-difluoro-4-(tetrahydro-2H-pyran-2 - yloxy)oct-1 -enyl)hexahydro-2H-cyclopenta[b]furan-2,5-diol may be synthesized as described for example 2, step E.

Step F: Preparation of (Z)-7-((1 R,2R,3R,5S)-2-((E)-3,3-difluoro-4- (tetrahydro-2H-pyran-2-yloxy)oct-1-enyl)-3,5- dihvdroxycvclopentyl)riept-5-enoic acid

[000131] (Z)-7-((1 R,2R,3R,5S)-2-((E)-3,3-difluoro-4-(tetrahydro-2H-pyran- 2-yloxy)oct-1-enyl)-3,5-dihydroxycyclopentyl)hept-5-enoic acid may be synthesized as described for example 2, step F.

Step G: Preparation of (Z)-7-((1R,2R,3R)-2-((E)-3,3-difluoro-4- (tetrahydro-2H-pyran-2-yloxy)oct-1-enyl)-3-hvdroxy-5- oxocvclopentvDhept-5-enoic acid and (Z)-7-((1 R,2R,5S)-2-((E)- 3,3-difluoro-4-(tetrahvdro-2H-pyran-2-yloxy)oct-1-enyl)-5- hvdroxy-3-oxocvclopentyl)hept-5-enoic acid (2:1)

[000132] (Z)-7-((1 R,2R,3R,5S)-2-((E)-3,3-difluoro-4-(tetrahydro-2H-pyran- 2-yloxy)oct-1-enyl)-3,5-dihydroxycyclopentyl)hept-5-enoic acid is dissolved in acetone (0.1 M) and cooled to -25 ⁰ C. Jones reagent (1 mol eq.) is added dropwise with stirring. Upon completion, as judged by TLC, the reaction is quenched with isopropyl alcohol and the crude reaction mixture is diluted with ethyl acetate, washed three times with brine, and dried over magnesium sulfate. After filtration and solvent evaporation, the product is purified by flash chromatography using ethyl acetate-hexane as eluent to give (Z)-7- ((1 R,2R,3R)-2-((E)-3,3-difluoro-4-(tetrahvdro-2H-pyran-2-yloxy) oct-1 -enyl)-3- hvdroxy-5-oxocvclopentyl)hept-5-enoic acid and (Z)-7-((1 R,2R,5S)-2-((E)-3,3- difluoro-4-(tetrahvdro-2H-pyran-2-yloxy)oct-1-enyl)-5-hvdrox y-3- oxocvclopentyl)hept-5-enoic acid.

Step H: Preparation of (Z)-7-((1 R,2R,3R)-2-((E)-3,3-difluoro-4- hvdroxyoct-1-enyl)-3-hvdroxy-5-oxocyclopentyl)hept-5-enoic acid

[000133] (Z)-7-((1 R,2R,3R)-2-((E)-3,3-difluoro-4-hydroxyoct-1-enyl)-3- hydroxy-5-oxocyclopentyl)hept-5-enoic acid may be synthesized as described for example 2, step I.

Step I: Preparation of (Z)-7-((1 R,2R,5S)-2-((E)-3,3-difluoro-4- hvdroxyoct-1-enyl)-5-hvdroxy-3-oxocyclopentyl)hept-5-enoic acid

[000134] (Z)-7-((1 R,2R,5S)-2-((E)-3,3-difluoro-4-hydroxyoct-1 -enyl)-5- hydroxy-3-oxocyclopentyl)hept-5-enoic acid may be synthesized as described for example 2, step I.

Example 5 - Preparation of (Z)-7-((1R,2R,5S)-2-((E)-3,3-difluoro-4- hvdroxyoct-1-enyl)-5-hvdroxy-3-methylenecvclopentyl)hept-5-e noic acid

Example 6 - Preparation of (Z)-7-((1R,2R)-2-((E)-3,3-difluoro-4- hvdroxyoct-1-enyl)-3-methyl-5-oxocyclopent-3-enyl)hept-5-eno ic acid

Step A: Preparation of (Z)-methyl 7-((1 R,2R,5S)-2-((E)-3,3-difluoro-4- (tetrahvdro-2H-pyran-2-yloxy)oct-1-enyl)-5-hvdroxv-3- oxocyclopentvPhept-5-enoate

[000135] (Z)-methyl 7-((1 R,2R,5S)-2-((E)-3,3-difluoro-4-(tetrahydro-2H- pyran-2-yloxy)oct-1 -enyO-δ-hydroxy-S-oxocyclopentyOhept-δ-enoate may be synthesized as per example 2, step G.

Step B: Preparation of (Z)-methyl 7-((1 R,2R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3,3-difluoro-4-(tetrahvdro-2H- pyran- 2-yloxy)oct-1 -envD-3- oxocvclopentyl)hept-5-enoate

[000136] (Z)-methyl 7-((1 R,2R,5S)-5-(tert-butyldiphenylsiIyloxy)-2-((E)- 3,3-difluoro-4-(tetrahydro-2H-pyran-2-yloxy)oct-1-enyl)-3-ox ocyclopentyl)hept- 5-enoate may be synthesized as per example 2, step H.

Step C: Preapartioπ of (Z)-methyl 7-((1 R,2R,5S)-5-(tert- butyldiphenylsilyloxy)-2-((E)-3,3-difluoro-4-(tetrahydro-2H- pyran- 2-yloxy)oct-1-enyl)-3-methylenecvclopentyl)hept-5-enoate

[000137] (Z)-methyl 7-((1 R,2R,5S)-5-(tert-butyldiphenylsilyloxy)-2-((E)- 3,3-difluoro-4-(tetrahydro-2H-pyran-2-yloxy)oct-1-enyl)-3- methylenecyclopentyl)hept-5-enoate may be synthesized as per example 2, step K.

Step D: Preparation of (Z)-methyl 7-((1 R,2R,5S)-2-((E)-3,3-difluoro-4- (tetrahvdro-2H-pyran-2-yloxy)oct-1-enyl)-5-hvdroxy-3- methylenecvclopentvDhept-δ-enoate

[000138] (Z)-methyl 7-((1 R,2R,5S)-2-((E)-3,3-difluoro-4-(tetrahydro-2H- pyran-2-yloxy)oct-1-enyl)-5-hydroxy-3-methylenecyclopentyl)h ept-5-enoate may be synthesized as described for example 2, step M.

Step E: Preparation of (Z)-7-((1 R,2R,5S)-2-((E)-3,3-difluoro-4- (tetra h yd ro-2 H-p yran-2-yloxy) oct- 1 -enyl )-5-h yd roxy-3- methylenecvclopentyl)hept-5-enoic acid

[000139] (Z)-7-((1 R,2R,5S)-2-((E)-3,3-difluoro-4-(tetrahydro-2H-pyran-2- yloxy)oct-1-enyl)-5-hydroxy-3-methylenecycIopentyl)hept-5-en oic acid may be synthesized as described for example 2, step L.

Step F: Preparation of (Z)-7-((1 R,2R,5S)-2-((E)-3.3-difluoro-4- hydroxyoct-i-envD-δ-hvdroxy-S-methylenecvclopentyDhept-δ- enoic acid

[000140] (Z)-7-((1 R,2R,5S)-2-((E)-3,3-difluoro-4-hydroxyoct-1 -enyl)-5- hydroxy-3-methylenecyclopentyl)hept-5-enoic acidmay be synthesized as described for example 2, step I.

Step G: Preparation of (Z)-7-((1 R,2R)-2-((E)-3,3-difluoro-4-(tetrahvdro- 2H-pyran-2-yloxy)oct-1-enyl)-3-methyl-5-oxocvclopent-3- enyl)hept-5-enoic acid

[000141] (Z)-7-((1 R,2R)-2-((E)-3,3-difluoro-4-(tetrahydro-2H-pyran-2- yloxy)oct-1-enyi)-3-methyl-5-oxocyclopent-3-enyl)hept-5-enoi c acid may be synthesized as described for example 2, step N.

Step H: Preparation of (Z)-7-((1 R,2R)-2-((E)-3,3-difluoro-4-hydroxyoct- 1 -envP-S-methyl-δ-oxocyclopent-S-envDhept-δ-enoic acid

[000142] (Z)-7-((1 R,2R)-2-((E)-3,3-difluoro-4-hydroxyoct-1-enyl)-3-methyl- 5-oxocyclopent-3-enyl)hept-5-enoic acid may be synthesized as described for example 2, step I.

EP Receptor Binding and Agonism

[000143] The ability of compounds to bind the EP receptors and their selectivity for each receptor can be demonstrated in radioligand competition displacement binding experiments using the cell lines described above which stably overexpress the human EP receptors. The ability of compounds to activate the receptors can be demonstrated in second messenger functional assays, measuring changes in intracellular calcium for EPi and changes in cAMP formation for EP ₂ , EP ₃ and EP ₄ .

Test Details

Binding Ability to Human EP Receptors

[000144] Membranes are prepared from cells stably transfected with human EP receptor DNA. In brief, cells are cultured to confluence, scraped from culture flasks and centrifuged to pellet (800 x g, 5 minutes, 4 ⁰ C). Cells are washed twice with ice-cold homogenization buffer containing 10 nnM Tris- HCI, 1 mM EDTA, 250 mM sucrose, 1 mM PMSF, 300 μM indomethacin, pH 7.4, homogenized by sonication and centrifuged as before. The supernatant is stored on ice; the pellets are rehomogenized and respun. Supernatants are pooled and centrifuged at 100,000 x g for 10 minutes at 4 ⁰ C. The resultant membrane pellet is stored at -80 ⁰ C until use.

[000145] For assays, membranes from cells expressing human EP-i, EP ₂ , EP ₃ or EP ₄ receptors are added to assay buffer (10 mM MES, pH 6.0, 10 mM

MgCI ₂ , 1 mM EDTA, 3 μM indomethacin) containing 5 nM [ ³ H]-PGE ₂ (GE Healthcare) and 0.1 to 10,000 nM concentrations of compounds to be tested. Incubations are performed at suitable temperatures and times to allow equilibration to be reached. Non-specific binding is determined in the presence of 10 μM PGE ₂ . Reactions are terminated by the addition of ice- cold buffer followed by rapid filtration through Whatman GF/B filters. The filters are dried after washing, and membrane-bound radioactivity is quantified by scintillation counting.

[000146] The affinity or pKj of each compound for each receptor is calculated from the concentration causing 50 % radioligand displacement (IC ₅₀ ) using the Cheng-Prosoff equation:

Ki = IC ₅ o/[1+(radioligand concentration/radioligand Kd)]

Functional Assays: Effect of Compounds on Second Messenger Generation

[000147] The following sections describe in vitro assays to determine the effect of compounds on calcium mobilization, and on the induction or inhibition of cAMP generation, that is, to determine the functional efficacy of compounds at the EP ₁ (calcium mobilization), EP ₂ (induction of cAMP), EP ₃ (inhibition of forskolin-induced cAMP) or EP ₄ (induction of cAMP) receptor.

EP ₁ Receptor Agonism Assay (Intracellular Calcium Assay)

Functional Assay #1AGi

[000148] To test the ability of compounds to activate the EPi receptor, calcium mobilization experiments are performed. Cells expressing the EP ₁ receptor are plated in clear-bottom black 96-well plates in normal growth medium and grown to confluence. When the cells have reached confluence, the culture medium is replaced with 50 μl of Fluo-4 NW dye mix (Invitrogen) that is dissolved in Hank's balanced salt solution containing 20 mM HEPES, pH 7.4 and 2.5 mM probenecid. Experiments are initiated by the addition of

50 μl/well of vehicle or compound to be tested diluted in this same buffer. Plates are incubated for 30 minutes at 37 °C and then at room temperature for an additional 30 minutes. Calcium fluorescence is measured using an Analyst AD (Molecular Devices) with an excitation wavelength of 485 nm, emission wavelength of 560 nm, and emission cutoff of 505 nm. Responses are quantified as peak fluorescence intensity minus basal fluorescence intensity.

Alternative EPi Receptor Agonism Assay

Functional Assay #1 AGM

(Cerep, Catalog reference 722-55a; UNGRIN, M.D., SINGH L.M.R., STOCCO, R., SAS, D.E. and ABRAMOVITZ, M. (1999), An automated aequorin luminescence-based functional calcium assay for G-Protein-Coupled Receptors. Analytical Biochem., 272, 34.)

[000149] Evaluation of the agonist activity of compounds at the human EPi receptor in transfected HEK-293 cells, determined by measuring their effect on cytosolic Ca ²⁺ ion mobilization using a fluorimetric detection method. [000150] The cells are suspended in DMEM buffer (Invitrogen), then distributed in microplates at a density of 3.10 ⁴ cells/well. The fluorescent probe (Fluo4 NW, Invitrogen) mixed with probenicid in HBSS buffer (Invitrogen) complemented with 20 mM Hepes (Invitrogen) (pH 7.4) is then added into each well and equilibrated with the cells for 30 minutes at 37 ⁰ C then 30 minutes at 22 ⁰ C. Thereafter, the assay plates are positioned in a microplate reader (CellLux, PerkinElmer) which is used for the addition of the test compound, reference agonist or HBSS buffer (basal control), and the measurements of changes in fluorescence intensity which varies proportionally to the free cytosolic Ca ²⁺ ion concentration. For stimulated control measurements, PGE ₂ at 100 nM is added in separate assay wells. [000151] The results are expressed as a percent of the control response to 100 nM PGE ₂ . The standard reference agonist is PGE ₂ , which is tested in each experiment at several concentrations to generate a concentration- response curve from which its EC ₅₀ value is calculated.

EPi Receptor Antagonism Assay

Functional Assay #1ANT

(Cerep, Catalog reference 722-55b; UNGRIN, M. D., et al., ibid.) [000152] Evaluation of the antagonist activity of compounds at the human EPi receptor in transfected HEK-293 cells, determined by measuring their effect on agonist-induced cytosolic Ca ²⁺ ion mobilization using a fluorimetric detection method.

[000153] The cells are suspended in DMEM buffer (Invitrogen), then distributed in microplates at a density of 3.10 ⁴ cells/well. The fluorescent probe (Fluo4 NW, Invitrogen) mixed with probenicid in HBSS buffer (Invitrogen) complemented with 20 mM Hepes (Invitrogen) (pH 7.4) is then added into each well and equilibrated with the cells for 30 minutes at 37 °C then 30 minutes at 22 °C. Thereafter, the assay plates are positioned in a microplate reader (CellLux, PerkinElmer) which is used for the addition of the test compound, reference antagonist or HBSS buffer (basal control), then 5 minutes later 3 nM PGE ₂ , and the measurements of changes in fluorescence intensity which varies proportionally to the free cytosolic Ca ²⁺ ion concentration. The results are expressed as a percent inhibition of the control response to 3 nM PGE ₂ . The standard reference antagonist is SC 51322, which is tested in each experiment at several concentrations to generate a concentration-response curve from which its IC ₅₀ value is calculated.

EP ₂ and EP ₄ Receptor Agonism Assay (Cyclic AMP Induction Assay)

Functional Assay #2AGi and Functional Assay #4AGi, respectively [000154] To test the ability of compounds to activate the EP ₂ and EP ₄ receptors, accumulation of cAMP following treatment with these compounds is measured. Cells expressing the EP ₂ or EP ₄ receptor are plated in 24-well plates in normal growth medium and grown to confluence. When the cells have reached confluence, the medium is replaced with 450 Dl of serum-free medium containing 0.25 mM IBMX and 20 μM indomethacin. Cells are incubated in this medium for one hour. Fifty microliters of this same buffer containing various concentrations of PGE ₂ or compounds to be tested is subsequently added to the cells and the cells are incubated for fifteen to thirty

minutes to allow the accumulation of cAMP. Reactions are terminated by the addition of 500 μl of 10 % TCA. cAMP measurements of the cell lysates are performed using Cayman Chemical's commercially available cAMP EIA Kit following the instructions provided in the kit booklet.

Alternative EP ₂ Receptor Agonism Assay

Functional Assay #2AGii

(Cerep, Catalog reference 758-54a; WILSON, RJ. , RHODES, S.A., WOOD, R.L., SHIELD, V.J., NOEL, LS., GRAY, D.W. and GILES H. (2004), Functional pharmacology of human prostanoid EP ₂ and EP ₄ receptors, Eur. J. Pharmacol., 501, 49.)

[000155] Evaluation of the agonist activity of compounds at the human EP ₂ receptor in transfected CHO cells, determined by measuring their effects on cAMP production using the HTRF detection method. [000156] The cells are suspended in HBSS buffer (Invitrogen) complemented with HEPES 20 mM (pH 7.4) and 500 μM IBMX, then distributed in microplates at a density of 10 ⁴ cells/well and incubated for 30 minutes at 37 ⁰ C in the absence (control) or presence of the test compound or the reference agonist. For stimulated control measurements, separate assay wells contain 10 μM PGE ₂ . Following incubation, the cells are lysed and the fluorescence acceptor (D2-labeled cAMP) and fluorescence donor (anti-cAMP antibody labeled with europium cryptate) are added. After 60 minutes at room temperature, the fluorescence transfer is measured at λex=337 nm and λem=620 and 665 nm using a microplate reader (Rubystar, BMG). The cAMP concentration is determined by dividing the signal measured at 665 nm by that measured at 620 nm (ratio). The results are expressed as a percent of the control response to 10 μM PGE ₂ . The standard reference agonist is PGE ₂ , which is tested in each experiment at several concentrations to generate a concentration-response curve from which its EC5 ₀ value is calculated.

EP ₂ Receptor Antagonism Assay

Functional Assay #2ANT

(Cerep, Catalog reference 758-54b; WILSON, R.J., et al., ibid.) [000157] Evaluation of the antagonist activity of compounds at the human EP ₂ receptor in transfected CHO cells, determined by measuring their effects on agonist-induced cAMP production using the HTRF detection method. [000158] The cells are suspended in HBSS buffer (Invitrogen) complemented with HEPES 20 mM (pH 7.4) and 500 μM IBMX, then distributed in microplates at a density of 10 ⁴ cells/well and preincubated for 5 minutes at room temperature in the absence (control) or presence of the test compound or the reference antagonist. Thereafter, the reference agonist PGE ₂ is added at a final concentration of 300 nM. For basal control measurements, separate assay wells do not contain PGE ₂ . Following 30 minutes incubation at 37 ⁰ C, the cells are lysed and the fluorescence acceptor (D2-labeled cAMP) and fluorescence donor

(anti-cAMP antibody labeled with europium cryptate) are added. After 60 minutes at room temperature, the fluorescence transfer is measured at λex=337 nm and λem=620 and 665 nm using a microplate reader (Rubystar, BMG). The cAMP concentration is determined by dividing the signal measured at 665 nm by that measured at 620 nm (ratio). The results are expressed as a percent inhibition of the control response to 300 nM PGE ₂ . The standard reference antagonist is AH 6809, which is tested in each experiment at several concentrations to generate a concentration-response curve from which its IC ₅₀ value is calculated.

EP ₃ Receptor Agonism Assay (Inhibition of Forskolin-induced cAMP Generation Assay)

Functional Assay #3AG

[000159] To test the ability of compounds to activate the EP ₃ receptor, the decrease in cAMP accumulation induced by forskolin following treatment with compounds is measured. Cells expressing the EP ₃ receptor are plated in 24- well plates in normal growth medium and allowed to come to confluence.

When the cells have come to confluence, the medium is replaced with 450 μl of serum-free medium containing 0.25 mM IBMX and 20 μM indomethacin. Cells are incubated in this medium for one hour. Fifty microliters of this same buffer containing 3 μM forskolin and various concentrations of PGE ₂ or compounds to be tested are subsequently added to the cells. After incubation at 37 ⁰ C for 10 minutes, reactions are terminated by the addition of 500 μl of 10 % TCA. cAMP measurements of the cell lysates are performed using Cayman Chemical's cAMP EIA Kit following the instructions provided in the kit booklet.

Alternative EP ₄ Receptor Agonism Assay

Functional Assay #4AGii

(Cerep, Catalog reference 758-49a; WILSON, R.J., et al., ibid.) [000160] Evaluation of the agonist activity of compounds at the human EP ₄ receptor in transfected CHO cells, determined by measuring their effects on cAMP production using the HTRF detection method. [000161] The cells are suspended in HBSS buffer (Invitrogen) complemented with HEPES 20 mM (pH 7.4) and 500 μM IBMX, then distributed in microplates at a density of 2.10 ⁴ cells/well and incubated for 10 minutes at room temperature in the absence (control) or presence of the test compound or the reference agonist. For stimulated control measurements, separate assay wells contain 1 μM PGE ₂ .

Following incubation, the cells are lysed and the fluorescence acceptor (D2- labeled cAMP) and fluorescence donor (anti-cAMP antibody labeled with europium cryptate) are added. After 60 minutes at room temperature, the fluorescence transfer is measured at λex=337 nm and λem=620 and 665 nm using a microplate reader (Rubystar, BMG). The cAMP concentration is determined by dividing the signal measured at 665 nm by that measured at 620 nm (ratio). The results are expressed as a percent of the control response to 1 μM PGE ₂ . The standard reference agonist is PGE ₂ , which is tested in each experiment at several concentrations to generate a concentration-response curve from which its EC50 value is calculated.

EP ₄ Receptor Antagonism Assay

Functional Assay #4ANT

(Cerep, Catalog reference 758-49b; WILSON, R.J., et al., ibid.) [000162] Evaluation of the antagonist activity of compounds at the human EP ₄ receptor in transfected CHO cells, determined by measuring their effects on agonist-induced cAMP production using the HTRF detection method. [000163] The cells are suspended in HBSS buffer (Invitrogen) complemented with HEPES 20 mM (pH 7.4) and 500 μM IBMX, then distributed in microplates at a density of 2.10 ⁴ cells/well and preincubated for 5 minutes at room temperature in the absence (control) or presence of the test compound or the reference antagonist.

[000164] Thereafter, the reference agonist PGE ₂ is added at a final concentration of 10 nM. For basal control measurements, separate assay wells do not contain PGE ₂ . Following 10 minutes incubation at room temperature, the cells are lysed and the fluorescence acceptor (D2-labeled cAMP) and fluorescence donor (anti-cAMP antibody labeled with europium cryptate) are added. After 60 minutes at room temperature, the fluorescence transfer is measured at λex=337 nm and λem=620 and 665 nm using a microplate reader (Rubystar, BMG). The cAMP concentration is determined by dividing the signal measured at 665 nm by that measured at 620 nm (ratio). The results are expressed as a percent inhibition of the control response to 10 nM PGE ₂ . There is no standard reference antagonist for this assay.