BITTER TASTE MODULATORS

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 61/355,800, filed on June 17, 2010 and entitled "BITTER TASTE MODULATORS", the contents of which are hereby incorporated by reference in their entireties for all purposes.

FIELD OF THE INVENTION

This invention relates to the discovery of antagonist of human type 2 taste receptors (hT2Rs), the use of these antagonists for modulating taste perception, particularly bitter taste, and the preparation of these antagonists.

BACKGROUND OF THE INVENTION

The taste system provides sensory information about the chemical composition of the external world. Taste transduction is one of the most sophisticated forms of

chemical-triggered sensation in animals. Signaling of taste is found throughout the animal kingdom, from simple metazoans to the most complex of vertebrates. Mammals are believed to have five basic taste modalities: sweet, bitter, sour, salty, and umami (the taste of monosodium glutamate).

The physiology of bitter taste until quite recently was very poorly understood. Recent studies have started to shed light on the biology of taste (Lindemann, Nature (2001)). It is now known that many bitter compounds produce bitter taste by interacting with cell surface receptors. These receptors belong to the family of seven transmembrane domain receptors that interact with intracellular G proteins. A novel family of GPCRs, termed T2Rs, has been identified in humans and rodents (Adler et al., Cell 100(6):693-702 (2000); Chandrashekar et al, Cell 100(6): 703-711 (2000); Matsunami H, Montmayeur J P, Buck L B. Nature

404(6778): 601-4 (2000)). Several lines of evidence prior to the subject invention suggested that T2Rs mediate responses to bitter compounds. First, T2R genes are specifically expressed in subset of taste receptor cells of the tongue and palate epithelia. Second, the gene for one of the human T2Rs (hT2Rl) is located in a chromosomal locus that is linked to sensitivity to bitter compound 6-n-propyl-2-thiouracil in humans (Adler et al., (Id.) (2000)). Third, one of the mouse T2Rs (mT2R5) is located in a chromosomal locus that is linked to sensitivity to bitter compound cycloheximide in mice. It was also shown that mT2R5 can activate gustducin, G protein specifically expressed in taste cells and linked to bitter stimuli transduction (Wong et al, Nature 381 :796-800 (1996)). Gustducin activation by mT2R5 occurs only in response to cycloheximide (Chandrashekar et al, (Id.) (2000). Thus, it has been proposed that mT2R family mediates bitter taste response in mice, whereas hT2R family mediates bitter taste response in humans. Only one human T2R was suggested as having identified bitter ligand~hT2R4 was shown as being activated by denatonium (Chandrashekar et al, (Id.) 2000). However, effective denatonium concentrations used in the study (1.5 mM) were unusually high, i.e., were 10 ⁵ -fold higher than the reported bitter threshold for denatonium to humans (Saroli, Naturwissenschaften 71 :428-429 (1984)). Thus, no specific bitter ligand was convincingly matched to any hT2R. It has been also suggested that each hT2R is able to bind multiple bitter ligands. This hypothesis is based on the fact that hT2R family consists of only 25 identified members, whereas humans can recognize hundreds of different compounds as bitter. Sequences of hT2Rs have been previously reported and are discloses in published PCT applications by Zuker et al. (WO 01/18050 A2, (2001)) and Adler et al. (WO 01/77676 Al (2001)) both of which are incorporated by reference in their entirety herein.

One of the difficulties of studying T2R function is that these receptors are not readily expressed in cultured mammalian cell lines. To improve T2R expression an N-terminal sequence from well-expressed GPCR, rhodopsin, was attached to T2R sequences

(Chandrashekar et al., (Id.) 2000). This N-terminal tag also allowed easy monitoring of protein expression due to available antibody. In addition, SSTR3 tag (Bufe et al, Nat. Genet. 32:397-400 (2002)), a different N-terminal tag has been used to improve T2R expression. Whereas the incorporation of the rhodopsin tag improved expression of some T2Rs in mammalian cell lines, many of them still were not expressed well enough for functional studies. In a different approach mT2R5 was successfully expressed in insect Sf9 cells and used for functional studies using biochemical GTPyS binding assay (Chandrashekar et al, (Id.) 2000).

In Applicants' earlier patent applications, U.S. Application Ser. No. 09/825,882 now U.S. Patent No. 7,105,650, Applicants identified and provided the nucleic acid sequences and polypeptide sequences for a number of then-novel human taste receptors including hT2R51 , hT2R54, hT2R55, hT2R61, hT2R63, hT2R64, hT2R65, hT2R67, hT2R71, and hT2R75. Additionally in U.S. Application Ser. Nos. 11/182,942 and 10/628,464, the entireties of which are incorporated by reference herein, Applicants provided the polypeptide and DNA sequence for another identified novel human taste receptor named therein hT2R76.

Also, in U.S. Application Ser. Nos. 10/191,058, 12/222,918, and 12/656,936 incorporated by reference herein in its entirety, Applicants discovered ligands that

specifically activate different human T2Rs. Additionally, Applicants recently filed U.S. Application Ser. No. 11/455,693, the entirety of which is incorporated by reference herein, which further identified bitter ligands that specifically bind to other human T2Rs, and provided related assays.

Also, relating to practical utilities of the invention it has been reported that both T2Rs and TlRs taste receptors are expressed in the gastrointestinal system. For example, Wu et al., Proc, Natl. Acad. Sci, USA 99(4):2392-7(2002) report that T2Rs are expressed in

enterendocrine cells (STCl cells) as well as gustducin and transducin subunits and that these cells likely respond to bitter ligands in the gastrointestinal tract. Also, it has been reported by Chen et al, AM J. Physiol. Cell Phyisol. 291(4):C726-39 (2006) that bitter taste stimuli induce Ca++ signaling and cholecystokinin (CCK) release in enterendocrine STC-1 cells . Also, Rozengurt, A J Physiol Gastrointes Liver Physiol 291(2):G171-7 (2006) report that taste receptors in the gut likely play a role in molecular sensing the control of digestive functions, and hormonal and/or neuronal pathways and that they may play a role in the detection of harmful drugs and survival responses. Further, Sternini Am J Physiol

Gastrointest Liver Physiol. 292(2):G457-61 (2007) report that taste receptors in the gut may be involved in gastrointestinal functions such as molecular sensing, nutrient absorption, protection from harmful substances, and further suggest that an understanding of these mechanisms may be relevant to disease states and conditions such as feeding disorders, and inflammation. Further, it has been recently suggested by Mace et al, J Physiol. 2007 (Epub) that T2Rs and TlRs activate phospho lipase C beta 2, PLC beta2, and that there is likely a molecular intestinal sensing system in the gut similar to that present in lingual cells and that gastrointestinal cells such as brush cells or solitary chemosensory cells expressing taste receptors may result in GLUT2 increase and may play a role in nutrient sensing, and nutrition in the treatment of obesity and diabetes. Also, Cui et al, Curr Pharm Des. 12(35):4591-600 (2006) suggest that TlRs expressed in the gut may be used in assays for compounds in treating obesity and diabetes as well as artificial sweeteners.

However, notwithstanding what has been reported and the understanding that T2R members regulate bitter taste, and their possible role in gastrointestinal functions there exists a need for the identification of specific ligands which activate human bitter T2R taste receptors. A greater understanding of the binding properties of different T2Rs, particularly human T2Rs, would be highly beneficial as it will greater facilitate the use thereof in selecting compounds having desired taste modulatory properties, i.e., which block or inhibit the taste of specific bitter compounds. Also, it will provide for the identification of compounds for treating and modulating gastrointestinal functions and related diseases such as obesity, diabetes, food absorption, food sensing, eating disorders, and in the regulation of related hormones and peptides such as GLUT2, cholecystokin et al.

SUMMARY OF THE INVENTION

Toward that end, the present invention relates to the discovery that hT2R67 and/or hT2R61 regulate bitter taste and the identification of compounds that modulate the activation of hT2R67 and/or hT2R61in a screening assay.

In one embodiment, the present invention provides a compound having structural Formula (I):

or a salt or solvate thereof, wherein:

R ¹ is hydrogen, alkyl, or substituted alkyl;

R ² is -OR ³ or -NR ³ R ⁴ ;

Ar ¹ is aryl, substituted aryl, heteroaryl, or substituted heteroaryl;

A ¹ is alkyl, substituted alkyl, heteroalkyl, substituted heteroalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl, or substituted cycloheteroalkyl;

A ² is a covalent bond, Ci to C ₃ alkylene, substituted Ci to C ₃ alkylene, -C(0)OCR ³ R ⁴ - , or -C(0)NHCR ³ R ⁴ -;

X is a covalent bond, S, O, CH ₂ , NR ³ , -S(O)-, -S(0) ₂ -, -C(O)-, or -C(S)-;

Y ¹ and Y ² are independently C _\ to C ₃ alkylene or substituted C _\ to C ₃ alkylene;

a and b are independently 0 or 1, but are not both 0;

Z is -S(O)-, -S(0) ₂ -, -C(O)-, or -C(S)-; and R ³ and R ⁴ are independently hydrogen, alkyl or substituted alkyl; or R ³ and R ⁴ together with the atoms to which they are bonded, form a cycloheteroalkyl or substituted cycloheteroalkyl ring.

In another embodiment, the present invention provides a composition comprising a compound of the present invention.

In another embodiment, the present invention provides a method of reducing or alleviating the bitter taste of a composition comprising contacting the composition with a compound of the present invention to form a modified composition.

In another embodiment, the present invention provides a method of preparing the compound of Formula (I), or a salt or solvate thereof, in a purified form without

chromatographic purification.

In another embodiment, the present invention provides a method of preparing a salt of the compound of Formula (I), or a solvate thereof, in a purified form without

chromatographic purification.

DETAILED DESCRIPTION OF THE INVENTION

The compounds of the present invention can be used to modulate, e.g., alleviate or reduce, the bitter taste of compositions, e.g., an ingestible composition. These and other embodiments, advantages, and features of the present invention are provided in the sections below. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Definitions

The terms "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item, i.e., one or more. The term "or" or "and/or" is used as a function word to indicate that two words or expressions are to be taken together or individually. The terms "comprising", "having", "including", and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to"). The endpoints of all ranges directed to the same component or property are inclusive and independently combinable.

"Alkyl," by itself or as part of another substituent, refers to a saturated or unsaturated, branched, straight-chain or cyclic monovalent hydrocarbon radical derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane, alkene or alkyne. The term "alkyl" includes "cycloalkyl" as defined hereinbelow. Typical alkyl groups include, but are not limited to, methyl; ethyls such as ethanyl, ethenyl, ethynyl; propyls such as propan-l-yl, propan-2-yl, cyclopropan-l-yl, prop-l-en-l-yl, prop-l-en-2-yl, prop-2-en-l-yl (allyl), cycloprop-l-en-l-yl; cycloprop-2-en-l-yl, prop-l-yn-l-yl, prop-2-yn-l-yl, etc.; butyls such as butan-l-yl, butan-2-yl, 2-methyl-propan-l-yl, 2-methyl-propan-2-yl, cyclobutan-l-yl, but-l-en-l-yl, but-l-en-2-yl, 2-methyl-prop-l-en-l-yl, but-2-en-l-yl, but-2-en-2-yl, buta-l,3-dien-l-yl, buta-l,3-dien-2-yl, cyclobut-l-en-l-yl, cyclobut-l-en-3-yl,

cyclobuta-l,3-dien-l-yl, but-l-yn-l-yl, but-l-yn-3-yl, but-3-yn-l-yl, etc.; and the like. The term "alkyl" is specifically intended to include groups having any degree or level of saturation, i.e., groups having exclusively single carbon-carbon bonds, groups having one or more double carbon-carbon bonds, groups having one or more triple carbon-carbon bonds and groups having mixtures of single, double and triple carbon-carbon bonds. Where a specific level of saturation is intended, the expressions "alkanyl," "alkenyl," and "alkynyl" are used. In some embodiments, an alkyl group comprises from 1 to 20 carbon atoms (C ₁ -C ₂₀ alkyl). In other embodiments, an alkyl group comprises from 1 to 10 carbon atoms (C ₁ -C ₁₀ alkyl). In still other embodiments, an alkyl group comprises from 1 to 6 carbon atoms (Ci-C ₆ alkyl). It is noted that when an alkyl group is further connected to another atom, it becomes an "alkylene" group. In other words, the term "alkylene" refers to a divalent alkyl. For example, -CH ₂ CH ₃ is an ethyl, while -CH ₂ CH ₂ - is an ethylene. That is, "Alkylene," by itself or as part of another substituent, refers to a saturated or unsaturated, branched, straight-chain or cyclic divalent hydrocarbon radical derived by the removal of two hydrogen atoms from a single carbon atom or two different carbon atoms of a parent alkane, alkene or alkyne. The term "alkylene" includes "cycloalkylene" as defined hereinbelow. The term "alkylene" is specifically intended to include groups having any degree or level of saturation, i.e., groups having exclusively single carbon-carbon bonds, groups having one or more double carbon-carbon bonds, groups having one or more triple carbon-carbon bonds and groups having mixtures of single, double and triple carbon-carbon bonds. Where a specific level of saturation is intended, the expressions "alkanylene," "alkenylene," and "alkynylene" are used. In some embodiments, an alkylene group comprises from 1 to 20 carbon atoms (C ₁ -C ₂₀ alkylene). In other embodiments, an alkylene group comprises from 1 to 10 carbon atoms (C ₁ -C ₁₀ alkylene). In still other embodiments, an alkylene group comprises from 1 to 6 carbon atoms (Ci-C ₆ alkylene).

"Alkanyl," by itself or as part of another substituent, refers to a saturated branched, straight-chain or cyclic alkyl radical derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane. The term "alkanyl" includes "cycloakanyl" as defined hereinbelow. Typical alkanyl groups include, but are not limited to, methanyl; ethanyl;

propanyls such as propan-l-yl, propan-2-yl (isopropyl), cyclopropan-l-yl, etc.; butanyls such as butan-l-yl, butan-2-yl (sec-butyl), 2-methyl-propan-l-yl (isobutyl), 2-methyl-propan-2-yl (t-butyl), cyclobutan-l-yl, etc.; and the like.

"Alkenyl," by itself or as part of another substituent, refers to an unsaturated branched, straight-chain or cyclic alkyl radical having at least one carbon-carbon double bond derived by the removal of one hydrogen atom from a single carbon atom of a parent alkene. The term "alkenyl" includes "cycloalkenyl" as defined hereinbelow. The group may be in either the cis or trans conformation about the double bond(s). Typical alkenyl groups include, but are not limited to, ethenyl; propenyls such as prop-l-en-l-yl, prop-l-en-2-yl, prop-2-en-l-yl (allyl), prop-2-en-2-yl, cycloprop-l-en-l-yl; cycloprop-2-en-l-yl; butenyls such as but-l-en-l-yl, but-l-en-2-yl, 2-methyl-prop-l-en-l-yl, but-2-en-l-yl , but-2-en-l-yl, but-2-en-2-yl, buta-l,3-dien-l-yl, buta-l,3-dien-2-yl, cyclobut-l-en-l-yl, cyclobut-l-en-3-yl, cyclobuta-l,3-dien-l-yl, etc.; and the like.

"Alkynyl," by itself or as part of another substituent refers to an unsaturated branched, straight-chain or cyclic alkyl radical having at least one carbon-carbon triple bond derived by the removal of one hydrogen atom from a single carbon atom of a parent alkyne. Typical alkynyl groups include, but are not limited to, ethynyl; propynyls such as prop-l-yn-l-yl, prop-2-yn- 1 -yl, etc. ; butynyls such as but- 1 -yn- 1 -yl, but- 1 -yn-3 -yl, but-3 -yn- 1 -yl, etc. ; and the like.

"Alkoxy," by itself or as part of another substituent, refers to a radical of the formula -O-R ¹⁹⁹ , where R ¹⁹⁹ is alkyl or substituted alkyl as defined herein.

"Acyl" by itself or as part of another substituent refers to a radical -C(0)R ²⁰⁰ , where R ²⁰⁰ is hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, heteroalkyl, substituted heteroalkyl, heteroarylalkyl or substituted heteroarylalkyl as defined herein. Representative examples include, but are not limited to formyl, acetyl, cyclohexylcarbonyl, cyclohexylmethylcarbonyl, benzoyl, benzylcarbonyl and the like.

"Aryl," by itself or as part of another substituent, refers to a monovalent aromatic hydrocarbon group derived by the removal of one hydrogen atom from a single carbon atom of a parent aromatic ring. An "aromatic ring" refers to an organic compound having a conjugated planar ring system composed of carbon atoms and with delocalized pi electron clouds. As used herein, "aryl" includes monocyclic and fused-polycyclic groups. Fused- polycyclic group refers to a chemical moiety which contains two or more rings wherein at least one of the rings is an aromatic ring and these two or more rings share one or more connecting bond. For example, the fused-polycyclic aryl may be derived from naphthalene, anthracene, or tetrahydronaphthalene. The fused-polycyclic group can be fused-bicyclic, fused-tricyclic, or fused-tetracyclic. In a fused-polycyclic aryl, the fused multiple rings may all be aromatic, or one or more of the multiple rings is aromatic while others are not. The monocyclic aryl or fused-polycyclic aryl may be optionally substituted. Typical aryl groups include, but are not limited to, groups derived from aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene, hexalene, as-indacene, s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene, rubicene, triphenylene, trinaphthalene and the like. In some embodiments, an aryl group comprises from 6 to 20 carbon atoms (C ₆ -C ₂₀ aryl). In other embodiments, an aryl group comprises from 6 to 15 carbon atoms (C ₆ -C ₁₅ aryl). In still other embodiments, an aryl group comprises from 6 to 15 carbon atoms (C ₆ -Cio aryl).

"Arylalkyl," by itself or as part of another substituent, refers to 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 as, as defined herein. Typical arylalkyl groups include, but are not limited to, benzyl, 2-phenylethan-l-yl, 2-phenylethen-l-yl,

naphthylmethyl, 2-naphthylethan-l-yl, 2-naphthylethen-l-yl, naphthobenzyl,

2-naphthophenylethan-l-yl and the like. Where specific alkyl moieties are intended, the nomenclature arylalkanyl, arylalkenyl and/or arylalkynyl is used. In some embodiments, an arylalkyl group is (C ₆ -C30) arylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety of the arylalkyl group is (C ₁ -C ₁₀ ) alkyl and the aryl moiety is (C ₆ -C ₂₀ ) aryl. In other embodiments, an arylalkyl group is (C ₆ -C ₂₀ ) arylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety of the arylalkyl group is (Ci-Cs) alkyl and the aryl moiety is (C ₆ -C ₁₂ ) aryl. In still other

embodiments, an arylalkyl group is (C ₆ -C ₁₅ ) arylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety of the arylalkyl group is (C ₁ -C5) alkyl and the aryl moiety is (C ₆ -Cio) aryl.

"Cycloalkyl," by itself or as part of another substituent, refers to a saturated or unsaturated cyclic alkyl radical, as defined herein. Similarly, "Cycloalkylene," by itself or as part of another substituent, refers to a saturated or unsaturated cyclic alkylene radical, as defined herein. Where a specific level of saturation is intended, the nomenclature

"cycloalkanyl", "cycloalkenyl", or "cycloalkynyl" is used. Typical cycloalkyl groups include, but are not limited to, groups derived from cyclopropane, cyclobutane, cyclopentane, cyclohexane, and the like. In some embodiments, the cycloalkyl group comprises from 3 to 10 ring atoms (C ₃ -C ₁₀ cycloalkyl). In other embodiments, the cycloalkyl group comprises from 3 to 7 ring atoms (C3-C7 cycloalkyl). The cycloalkyl may be further substituted by one or more heteroatoms including, but not limited to, N, P, O, S, and Si, which attach to the carbon atoms of the cycloalkyl via monovalent or multivalent bond.

"Heteroalkyl," "Heteroalkanyl," "Heteroalkenyl" and "Heteroalkynyl," by themselves or as part of other substituents, refer to alkyl, alkanyl, alkenyl and alkynyl groups, respectively, in which one or more of the carbon atoms (and optionally any associated hydrogen atoms), are each, independently of one another, replaced with the same or different heteroatoms or heteroatomic groups. Similarly, "Heteroalkylene," "Heteroalkanylene,"

"Heteroalkenylene" and "Heteroalkynylene," by themselves or as part of other substituents, refer to alkylene, alkanylene, alkenylene and alkynyenel groups, respectively, in which one or more of the carbon atoms (and optionally any associated hydrogen atoms), are each, independently of one another, replaced with the same or different heteroatoms or

heteroatomic groups. Typical heteroatoms or heteroatomic groups which can replace the carbon atoms include, but are not limited to, -0-, -S-, -N-, -Si-, -NH-, -S(O)-, -S(0) ₂ -, -S(0)NH-, -S(0) ₂ NH- and the like and combinations thereof. The heteroatoms or

heteroatomic groups may be placed at any interior position of the alkyl, alkenyl or alkynyl groups. Typical heteroatomic groups which can be included in these groups include, but are not limited to, -0-, -S-, -O-O-, -S-S-, -0-S-, -NR ²⁰¹ R ²⁰² -, =N-N=, -N=N-, -N=N-NR ²⁰³ R ²⁰⁴ , -PR ²⁰⁵ -, -P(0) ₂ -, -POR ²⁰⁶ -, -0-P(0) ₂ -, -SO-, -S0 ₂ -, -SnR ²⁰⁷ R ²⁰⁸ - and the like, where R ²⁰¹ , R ²⁰² , R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ , R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ are independently hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl, substituted cycloheteroalkyl, heteroalkyl, substituted heteroalkyl, heteroaryl, substituted heteroaryl, heteroarylalkyl or substituted heteroarylalkyl.

"Cycloheteroalkyl," or "Heterocyclyl,"by itself or as part of another substituent, refers to a saturated or unsaturated cyclic alkyl radical in which one or more carbon atoms (and optionally any associated hydrogen atoms) are independently replaced with the same or different heteroatom. Similarly, "Cycloheteroalkylene," by itself or as part of another substituent, refers to a saturated or unsaturated cyclic alkylene radical in which one or more carbon atoms (and optionally any associated hydrogen atoms) are independently replaced with the same or different heteroatom. The cycloheteroalkyl may be further substituted by one or more heteroatoms including, but not limited to, N, P, O, S, and Si, which attach to the carbon atoms of the cycloheteroalkyl via monovalent or multivalent bond. Typical heteroatoms to replace the carbon atom(s) include, but are not limited to, N, P, O, S, Si, etc. Where a specific level of saturation is intended, the nomenclature "cycloheteroalkanyl" or "cycloheteroalkenyl" is used. Typical cycloheteroalkyl groups include, but are not limited to, groups derived from epoxides, azirines, thiiranes, imidazolidine, morpholine, piperazine, piperidine, pyrazolidine, pyrrolidone, quinuclidine, and the like. In some embodiments, the cycloheteroalkyl group comprises from 3 to 10 ring atoms (3-10 membered cycloheteroalkyl) In other embodiments, the cycloalkyl group comprise from 5 to 7 ring atoms (5-7 membered cycloheteroalkyl). A cycloheteroalkyl group may be substituted at a heteroatom, for example, a nitrogen atom, with a (Ci-C ₆ ) alkyl group. As specific examples,

N-methyl-imidazolidinyl, N-methyl-morpholinyl, N-methyl-piperazinyl,

N-methyl-piperidinyl, N-methyl-pyrazolidinyl and N-methyl-pyrrolidinyl are included within the definition of "cycloheteroalkyl." A cycloheteroalkyl group may be attached to the remainder of the molecule via a ring carbon atom or a ring heteroatom.

"Compound" refers to a compound encompassed by structural formulae disclosed herein and includes any specific compounds within these formulae whose structure is disclosed herein. Compounds may be identified either by their chemical structure and/or chemical name. When the chemical structure and chemical name conflict, the chemical structure is determinative of the identity of the compound. The compounds described herein may contain one or more chiral centers and/or double bonds and therefore, may exist as stereoisomers, such as double-bond isomers {i.e. , geometric isomers), enantiomers or diastereomers. Accordingly, the chemical structures depicted herein encompass all possible enantiomers and stereoisomers of the illustrated compounds including the stereoisomerically pure form {e.g. , geometrically pure, enantiomerically pure or diastereomerically pure) and enantiomeric and stereoisomeric mixtures. Enantiomeric and stereoisomeric mixtures can be resolved into their component enantiomers or stereoisomers using separation techniques or chiral synthesis techniques well known to the skilled artisan. The compounds may also exist in several tautomeric forms including the enol form, the keto form and mixtures thereof. Accordingly, the chemical structures depicted herein encompass all possible tautomeric forms of the illustrated compounds. The term "tautomer" as used herein refers to isomers that change into one another with great ease so that they can exist together in equilibrium. In general, compounds may be hydrated, solvated or N-oxides. Certain compounds may exist in multiple crystalline or amorphous forms. In general, all physical forms are equivalent for the uses contemplated herein and are intended to be within the scope of the present invention. Further, it should be understood, when partial structures of the compounds are illustrated, that brackets indicate the point of attachment of the partial structure to the rest of the molecule.

"Halo," by itself or as part of another substituent refers to a radical -F, -CI, -Br or -I. "Heteroaryl," by itself or as part of another substituent, refers to a monovalent heteroaromatic radical derived by the removal of one hydrogen atom from a single atom of a parent heteroaromatic ring. A "heteroaromatic ring" refers to an aromatic ring wherein one or more of the carbon atoms, which constitute the conjugated ring system, is replaced with one or more heteroatom, such as, nitrogen, oxygen, sulfur, phosphorus, boron silicon, etc. As used herein, "heteroaryl" includes monocyclic and fused-polycyclic groups. Fused- polycyclic group refers to a chemical moiety which contains two or more rings wherein at least one of the rings is an aromatic ring and these two or more rings share one or more connecting bond. For example, the fused-polycyclic heteroaryl may be derived from benzofuran, isobenzofuran, indole, isoindole, benzothiophene, isobenzothiophene, benzimidazole, purine, indazole, benzoxazole, benzothiazole, benzisoxazole, or

dihydrobenzofuran. The fused-polycyclic group can be fused-bicyclic, fused-tricyclic, or fused-tetracyclic. In a fused-polycyclic heteroaryl, the fused multiple rings may all be aromatic, or one or more of the multiple rings is aromatic while others are not. The monocyclic aryl or fused-polycyclic aryl may be optionally substituted. Typical heteroaryl groups include, but are not limited to, groups derived from acridine, β-carboline, chromane, chromene, cinnoline, furan, imidazole, indazole, indole, indoline, indolizine, isobenzofuran, isochromene, isoindole, isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline, phenazine, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline, quinoline, quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole, thiophene, triazole, xanthene, and the like. In some embodiments, the heteroaryl group comprises from 5 to 20 ring atoms (5-20 membered heteroaryl). In other embodiments, the heteroaryl group comprises from 5 to 10 ring atoms (5-10 membered heteroaryl). Exemplary heteroaryl groups include those derived from furan, thiophene, pyrrole, benzothiophene, benzofuran, benzimidazole, indole, pyridine, pyrazole, quinoline, imidazole, oxazole, isoxazole and pyrazine.

"Heteroarylalkyl" by itself or as part of another substituent refers to 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 a heteroaryl group. Where specific alkyl moieties are intended, the nomenclature heteroarylalkanyl, heteroarylakenyl and/or heteroarylalkynyl is used. In some embodiments, the heteroarylalkyl group is a 6-21 membered heteroarylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety of the heteroarylalkyl is (Ci-C ₆ ) alkyl and the heteroaryl moiety is a 5-15-membered heteroaryl. In other embodiments, the heteroarylalkyl is a 6-13 membered heteroarylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety is (C ₁ -C3) alkyl and the heteroaryl moiety is a 5-10 membered heteroaryl.

"Protecting group" refers to a grouping of atoms that when attached to a reactive functional group in a molecule masks, reduces or prevents reactivity of the functional group. Examples of protecting groups can be found in Green et ah, "Protective Groups in Organic Chemistry", (Wiley, 2 ^nd ed. 1991) and Harrison et al., "Compendium of Synthetic Organic Methods", Vols. 1-8 (John Wiley and Sons, 1971-1996). Representative amino protecting groups include, but are not limited to, formyl, acetyl, trifluoroacetyl, benzyl,

benzyloxycarbonyl ("CBZ"), tert-butoxycarbonyl ("Boc"), trimethylsilyl ("TMS"),

2-trimethylsilyl-ethanesulfonyl ("SES"), trityl and substituted trityl groups, allyloxycarbonyl, 9-fluorenylmethyloxycarbonyl ("FMOC"), nitro-veratryloxycarbonyl ("NVOC") and the like. Representative hydroxy protecting groups include, but are not limited to, those where the hydroxy group is either acylated or alkylated such as benzyl, and trityl ethers as well as alkyl ethers, tetrahydropyranyl ethers, trialkylsilyl ethers and allyl ethers.

"Salt" refers to a salt of a compound, which possesses the desired pharmacological activity of the parent compound. Such salts include: (1) acid addition salts, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids such as acetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4-hydroxybenzoyl) benzoic acid, cinnamic acid, mandelic acid,

methanesulfonic acid, ethanesulfonic acid, 1 ,2-ethane-disulfonic acid,

2-hydroxyethanesulfonic acid, benzenesulfonic acid, 4-chlorobenzenesulfonic acid,

2-naphthalenesulfonic acid, 4-toluenesulfonic acid, camphorsulfonic acid,

4-methylbicyclo[2.2.2]-oct-2-ene-l-carboxylic acid, glucoheptonic acid, 3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid, and the like; or (2) salts formed when an acidic proton present in the parent compound is replaced by a metal ion, e.g. , an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic base such as ethanolamine, diethanolamine, triethanolamine,

N-methylglucamine and the like. "Solvate" means a compound formed by solvation (the combination of solvent molecules with molecules or ions of the solute), or an aggregate that consists of a solute ion or molecule, i.e., a compound of the present invention, with one or more solvent molecules. When water is the solvent, the corresponding solvate is "hydrate".

"N-oxide", also known as amine oxide or amine-N-oxide, means a compound that derives from a compound of the present invention via oxidation of an amine group of the compound of the present invention. An N-oxide typically contains the functional group R ₃ N ⁺ -CT (sometimes written as R ₃ N=0 or R ₃ N→0).

"Substituted," when used to modify a specified group or radical, means that one or more hydrogen atoms of the specified group or radical are each, independently of one another, replaced with the same or different substituent(s). Substituent groups useful for substituting saturated carbon atoms in the specified group or radical include, but are not limited to -R ^a , halo, -O , =0, -OR ^b , -SR ^b , -S ^~ , =S, -NR ^C R ^C , =NR ^b , =N-OR ^b , trihalomethyl, -CF ₃ , -CN, -OCN, -SCN, -NO, -N0 ₂ , =N ₂ , -N ₃ , -S(0) ₂ R ^b , -S(0) ₂ NR ^b , -S(0) ₂ 0 ^" , -S(0) ₂ OR ^b , -OS(0) ₂ R ^b , -OS(0) ₂ 0 ^" , -OS(0) ₂ OR ^b , -P(0)(0 ) ₂ , -P(0)(OR ^b )(0 ), -P(0)(OR ^b )(OR ^b ),

-C(0)R ^b , -C(S)R ^b , -C(NR ^b )R ^b , -C(0)0 ^" , -C(0)OR ^b , -C(S)OR ^b , -C(0)NR ^c R ^c , -C(NR ^b )NR ^c R ^c , -OC(0)R ^b , -OC(S)R ^b , -OC(0)0 ^" , -OC(0)OR ^b , -OC(S)OR ^b , -NR ^b C(0)R ^b , -NR ^b C(S)R ^b , -NR ^b C(0)0 ^" , -NR ^b C(0)OR ^b , -NR ^b C(S)OR ^b , -NR ^b C(0)NR ^c R ^c , -NR ^b C(NR ^b )R ^b and

-NR ^b C(NR ^b )NR ^c R ^c , where R ^a is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, cycloheteroalkyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl; each R ^b is independently hydrogen or R ^a ; and each R ^c is independently R ^b or alternatively, the two R ^c s may be taken together with the nitrogen atom to which they are bonded form a 4-, 5-, 6- or 7-membered cycloheteroalkyl which may optionally include from 1 to 4 of the same or different additional heteroatoms selected from the group consisting of O, N and S. As specific examples, -NR ^C R ^C is meant to include -NH ₂ , -NH-alkyl, N-pyrrolidinyl and

N-morpholinyl. As another specific example, a substituted alkyl is meant to include - alkylene-O-alkyl, -alkylene-heteroaryl, -alkylene-cycloheteroalkyl, -alkylene-C(0)OR ^b , - alkylene-C(0)NR ^b R ^b , and -CH ₂ -CH ₂ -C(0)-CH ₃ . The one or more substituent groups, taken together with the atoms to which they are bonded, may form a cyclic ring including cycloalkyl and cycloheteroalkyl.

Similarly, substituent groups useful for substituting unsaturated carbon atoms in the specified group or radical include, but are not limited to, -R ^a , halo, -O ^" , -OR ^b , -SR ^b , -S ^" , -NR ^C R ^C , trihalomethyl, -CF ₃ , -CN, -OCN, -SCN, -NO, -N0 ₂ , -N ₃ , -S(0) ₂ R ^b , -S(0) ₂ 0 ^" , -S(0) ₂ OR ^b , -OS(0) ₂ R ^b , -OS(0) ₂ 0 ^" , -OS(0) ₂ OR ^b , -P(0)(0 ) ₂ , -P(0)(OR ^b )(0 ), -P(0)(OR ^b )(OR ^b ), -C(0)R ^b , -C(S)R ^b , -C(NR ^b )R ^b , -C(0)0 ^~ , -C(0)OR ^b , -C(S)OR ^b ,

-C(0)NR ^c R ^c , -C(NR ^b )NR ^c R ^c , -OC(0)R ^b , -OC(S)R ^b , -OC(0)0 ^~ , -OC(0)OR ^b , -OC(S)OR ^b , -NR ^b C(0)R ^b , -NR ^b C(S)R ^b , -NR ^b C(0)0 ^~ , -NR ^b C(0)OR ^b , -NR ^b C(S)OR ^b , -NR ^b C(0)NR ^c R ^c , -NR ^b C(NR ^b )R ^b and -NR ^b C(NR ^b )NR ^c R ^c , where R ^a , R ^b and R ^c are as previously defined.

Substituent groups useful for substituting nitrogen atoms in heteroalkyl and cycloheteroalkyl groups include, but are not limited to, -R ^a , -O ^" , -OR ^b , -SR ^b , -S ^" , -NR ^C R ^C , trihalomethyl, -CF ₃ , -CN, -NO, -N0 ₂ , -S(0) ₂ R ^b , -S(0) ₂ 0 ^~ , -S(0) ₂ OR ^b , -OS(0) ₂ R ^b ,

-OS(0) ₂ 0 ^" , -OS(0) ₂ OR ^b , -P(0)(0 ) ₂ , -P(0)(OR ^b )(0 ), -P(0)(OR ^b )(OR ^b ), -C(0)R ^b , -C(S)R ^b , -C(NR ^b )R ^b , -C(0)OR ^b , -C(S)OR ^b , -C(0)NR ^c R ^c , -C(NR ^b )NR ^c R ^c , -OC(0)R ^b , -OC(S)R ^b , -OC(0)OR ^b , -OC(S)OR ^b , -NR ^b C(0)R ^b , -NR ^b C(S)R ^b , -NR ^b C(0)OR ^b , -NR ^b C(S)OR ^b , -NR ^b C(0)NR ^c R ^c , -NR ^b C(NR ^b )R ^b and -NR ^b C(NR ^b )NR ^c R ^c , where R ^a , R ^b and R ^c are as previously defined.

Substituent groups from the above lists useful for substituting other specified groups or atoms will be apparent to those of skill in the art.

The substituents used to substitute a specified group can be further substituted, typically with one or more of the same or different groups selected from the various groups specified above.

"Carrier" refers to a diluent, adjuvant, excipient or vehicle with which a compound is ingested or administered.

The term "composition" denotes one or more substance in a physical form, such as solid, liquid, gas, or a mixture thereof. As used herein, an "ingestible composition" includes any substance that, either alone or together with another substance, can be taken by mouth whether intended for consumption or not. The ingestible composition includes both "food or beverage products" and "non-edible products". By "Food or beverage products", it is meant any edible product intended for consumption by humans or animals, including solids, semisolids, or liquids (e.g., beverages). The term "non-edible products" or "noncomestible composition" includes supplements, nutraceuticals, functional food products (e.g., any fresh or processed food claimed to have a health-promoting and/or disease-preventing properties beyond the basic nutritional function of supplying nutrients), pharmaceutical and over the counter medications, oral care products such as dentifrices and mouthwashes, cosmetic products, and other personal care products that have a bitter taste.

A "ingestibly acceptable carrier or excipient" is a solid or liquid medium and/or composition that is used to prepare a desired dispersed dosage form of the inventive compound, in order to administer the inventive compound in a dispersed/diluted form, so that the biological effectiveness of the inventive compound is maximized. Ingestibly acceptable carriers includes many common food ingredients, such as water at neutral, acidic, or basic pH, fruit or vegetable juices, vinegar, marinades, beer, wine, natural water/fat emulsions such as milk or condensed milk, edible oils and shortenings, fatty acids and their alkyl esters, low molecular weight oligomers of propylene glycol, glyceryl esters of fatty acids, and dispersions or emulsions of such hydrophobic substances in aqueous media, salts such as sodium chloride, wheat flours, solvents such as ethanol, solid edible diluents such as vegetable powders or flours, or other liquid vehicles; dispersion or suspension aids; surface active agents; isotonic agents; thickening or emulsifying agents, preservatives; solid binders; lubricants and the like.

A "modulator" herein refers to a compound that modulates the activation of a particular receptor, preferably the chemosensory, e.g., T2R61 and/or T2R67 receptor.

A "flavor" herein refers to the perception of taste in a subject, which include sweet, sour, salty, bitter and umami. The subject may be a human or an animal.

A "flavoring agent" herein refers to a compound or a biologically acceptable salt or solvate thereof that induces a flavor or taste in an animal or a human.

A "flavor modifier" herein refers to a compound or biologically acceptable salt or solvate thereof that modulates, including reducing or alleviating, and inducing, the tastes of a natural or synthetic flavoring agent in an animal or a human.

A "bitter flavor modulating amount" herein refers to an amount of a compound of

Formula (I) that is sufficient to alter, e.g., decrease, the bitter taste in a composition, or a precursor thereof, sufficiently to be perceived by a human subject. In many embodiments of the invention, at least about 0.001 ppm of the present compound would need to be present in order for most human subjects to perceive a modulation of the bitter flavor of an ingestible composition comprising the present compound. A broad range of concentration that would typically be employed in order to economically provide a desirable degree of bitter flavor modulation can be from about 0.001 ppm to 100 ppm, or a narrow range from about 0.1 ppm to about 10 ppm. Alternative ranges of bitter flavor modulating amounts can be from about 0.01 ppm to about 30 ppm, from about 0.05 ppm to about 15 ppm, from about 0.1 ppm to about 5 ppm, or from about 0.1 ppm to about 3 ppm.

A "bitter flavor reducing amount" herein refers to an amount of a compound that is sufficient to reduce the taste of a natural or synthetic bitter flavor/taste in a composition, as perceived by an animal or a human. A broad range of a bitter flavor reducing amount can be from about 0.001 ppm to 100 ppm, or a narrow range from about 0.1 ppm to about 10 ppm. Alternative ranges of bitter flavor reducing amounts can be from about 0.01 ppm to about 30 ppm, from about 0.05 ppm to about 15 ppm, from about 0.1 ppm to about 5 ppm, or from about 0.1 ppm to about 3 ppm.

Compounds

In one embodiment, the present invention provides a compound having structural Formula (I):

or a salt or solvate thereof, wherein:

R is hydrogen, alkyl, or substituted alkyl;

R ² is -OR ³ or -NR ³ R ⁴ ;

Ar ¹ is aryl, substituted aryl, heteroaryl, or substituted heteroaryl;

A ¹ is alkyl, substituted alkyl, heteroalkyl, substituted heteroalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl, or substituted cycloheteroalkyl;

A ² is a covalent bond, Ci to C ₃ alkylene, substituted Ci to C ₃ alkylene, -C(0)OCR ³ R ⁴ - , or -C(0)NHCR ³ R ⁴ -;

X is a covalent bond, S, O, CH ₂ , NR ³ , -S(O)-, -S(0) ₂ -, -C(O)-, or -C(S)-;

Y ¹ and Y ² are independently Ci to C ₃ alkylene or substituted Ci to C ₃ alkylene;

a and b are independently 0 or 1, but are not both 0;

Z is -S(O)-, -S(0) ₂ -, -C(O)-, or -C(S)-; and

R ³ and R ⁴ are independently hydrogen, alkyl or substituted alkyl; or R ³ and R ⁴ together with the atoms to which they are bonded, form a cycloheteroalkyl or substituted cycloheteroalkyl ring.

In one embodiment of structural Formula (I), Z is -S(0) ₂ - or -C(O)-.

In one embodiment of structural Formula (I), A ² is a covalent bond; and R ² is -OR ³ .

In one embodiment of structural Formula (I), A ² is Ci to C ₃ alkylene; and R ² is -OR ³ .

In one embodiment of structural Formula (I), A ² is -C(0)NHCR ³ R ⁴ -; and R ² is -OR ³ .

In one embodiment of structural Formula (I), Ar ¹ is monocyclic aryl, substituted monocyclic aryl, monocyclic heteroaryl, substituted monocyclic heteroaryl, fused-bicyclic aryl, substituted fused-bicyclic aryl, fused-bicyclic heteroaryl, or substituted fused-bicyclic heteroaryl. Examples of Ar ¹ include, but are not limited to, phenyl, substituted phenyl, naphthyl, substituted naphthyl, furanyl, substituted furanyl, benzofuran, substituted benzofuran, indole, substituted indole, benzothiophene, substituted benzothiophene, benzooxazole, substituted benzooxazole, pyrazolopyridine, substituted pyrazolopyridine, dihydrobenzofuran, substituted dihydrobenzofuran, thienopyridine, substituted

thienopyridine, thienopyrazole, substituted thienopyrazole, thienopyrazine, substituted thienopyrazine, chromen-2-one, substituted chromen-2-one, quinolin-2-one, and substituted quinolin-2-one.

In one embodiment of structural Formula (I), A ¹ is alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, monocyclic aryl, substituted monocyclic aryl, monocyclic heteroaryl, substituted monocyclic heteroaryl, fused-bicyclic aryl, substituted fused-bicyclic aryl, fused- bicyclic heteroaryl, or substituted fused-bicyclic heteroaryl.

In one embodiment of structural Formula (I), A ¹ is selected from the group consisting of Ci to C ₆ alkyl, substituted Ci to C ₆ alkyl, C ₃ to C ₇ cycloalkyl, substituted C ₃ to C ₇ cycloalkyl, phenyl, substituted phenyl, naphthyl, substituted naphthyl, furanyl, substituted furanyl, benzofuran, substituted benzofuran, indole, substituted indole, benzothiophene, substituted benzothiophene, benzooxazole, substituted benzooxazole, pyrazolopyridine, substituted pyrazolopyridine, dihydrobenzofuran, substituted dihydrobenzofuran,

thienopyridine, substituted thienopyridine, thienopyrazole, substituted thienopyrazole, thienopyrazine, substituted thienopyrazine, chromen-2-one, substituted chromen-2-one, quinolin-2-one, and substituted quinolin-2-one.

In one embodiment of structural Formula (I), Y ¹ and Y ² are independently Ci to C ₃ alkylene or substituted Ci to C ₃ alkylene; a and b are 1; and X is S, O, CH ₂ ,NR ³ , -S(O)-, - S(0) ₂ -, -C(O)-, or -C(S)-.

In one embodiment of structural Formula (I), Y ¹ is Ci to C ₃ alkylene or substituted Ci to C ₃ alkylene; a is 1; b is 0; and X is a covalent bond.

In one embodiment of the present invention, the compound of structural Formula (I) has a structural Formula (II):

or a salt or solvate thereof, wherein:

Ar ¹ and Ar ² are independently aryl, substituted aryl, heteroaryl, or substituted heteroaryl; X is a covalent bond; and a and b are independently 0 or 1, but are not both 0.

In one embodiment of the present invention, the compound of structural Formula (I) has a structural Formula (III):

or a salt or solvate thereof, wherein:

Ar ¹ and Ar ² are independently aryl, substituted aryl, heteroaryl, or substituted heteroaryl; and X is S, O, CH ₂ , or NR ³ .

In one embodiment of the present invention, the compound of structural Formula (I) has a structural Formula (IV):

or a salt or solvate thereof, wherein:

Ar ¹ and Ar ² are independently aryl, substituted aryl, heteroaryl, or substituted heteroaryl.

In one embodiment of structural Formula (IV), the compound has a structure of the following: , or a mixture thereof. In one embodiment of structural Formula (II), (III), or (IV), Ar ¹ and Ar ² are independently monocyclic aryl, substituted monocyclic aryl, monocyclic heteroaryl, substituted monocyclic heteroaryl, fused-bicyclic aryl, substituted fused-bicyclic aryl, fused- bicyclic heteroaryl, or substituted fused-bicyclic heteroaryl.

In some specific embodiments, the present invention provides compounds having the following structures:

22 Compositions

The present compounds can be used for one or more methods of the present invention, e.g., modulating, e.g., reducing or alleviating, a bitter taste. The present compounds can reduce or alleviate the bitter taste in a composition, such as coffee, coffee-flavored product, or a composition containing a whey protein, by contacting the present compounds with a composition to form a modified composition. In general, the compounds of the present invention are provided in compositions, such as, e.g., an ingestible composition. The ingestible composition includes both "food or beverage products" and "non-edible products". By "Food or beverage products", it is meant any edible product intended for consumption by humans or animals, including solids, semi-solids, or liquids (e.g., beverages). The term "non- edible products" or "noncomestible composition" includes supplements, nutraceuticals, functional food products (e.g., any fresh or processed food claimed to have a health- promoting and/or disease-preventing properties beyond the basic nutritional function of supplying nutrients), pharmaceutical and over the counter medications, oral care products such as dentifrices and mouthwashes, cosmetic products, and other personal care products that have bitter taste.

The ingestible composition also includes pharmaceutical, medicinal or comestible composition, or alternatively in a formulation, e.g., a pharmaceutical or medicinal

formulation or a food or beverage product or formulation.

The compounds of Formula (I) and its various subgenuses, and their salts, should preferably be comestibly acceptable, i.e. deemed suitable for consumption in food or drink from the perspective of giving unmodified comestible compositions an improved and/or reduced/alleviated bitter taste, and would not be significantly toxic or causes unpleasant or undesirable pharmacological or toxicological effects on an animal or human at the typically low concentrations they are employed as flavoring agents for the comestible compositions.

The typical method of demonstrating that a flavorant compound is comestibly acceptable is to have the compound tested and/or evaluated by an Expert Panel of the Flavor and Extract Manufacturers Association and declared as to be "Generally Recognized As Safe" ("GRAS"). The FEMA/GRAS evaluation process for flavorant compounds is complex but well known to those of ordinary skill in the food product preparation arts, as is discussed by Smith, et al. in an article entitled "GRAS Flavoring Substances 21," Food Technology, 57(5), pgs 46-59, May 2003, the entire contents of which are hereby incorporated herein by reference. The present compounds can also be provided, individually or in combination, with any ingestible composition known or later discovered. For example, the ingestible composition can be a comestible composition or noncomestible composition. By "comestible composition", it is meant any composition that can be consumed as food by humans or animals, including solids, gel, paste, foamy material, semi-solids, liquids,or mixtures thereof. By "noncomestible composition", it is meant any composition that is intended to be consumed or used by humans or animals not as food, including solids, gel, paste, foamy material, semi-solids, liquids, or mixtures thereof. The noncomestible composition includs, but is not limited to medical composition, which refers to a noncomestible composition intended to be used by humans or animals for therapeutic purposes. By "animal", it includes any non-human animal, such as, for example, farm animals and pets.

In one embodiment, the present compound is added to a noncomestible composition or non-edible product, such as supplements, nutraceuticals, functional food products (e.g., any fresh or processed food claimed to have a health-promoting and/or disease-preventing properties beyond the basic nutritional function of supplying nutrients), pharmaceutical and over the counter medications, oral care products such as dentifrices and mouthwashes, cosmetic products and other personal care products that have a bitter taste.

In general, over the counter (OTC) product and oral hygiene product generally refer to product for household and/or personal use which may be sold without a prescription and/or without a visit to a medical professional. Examples of the OTC products include, but are not limited to Vitamins and dietary supplements; Topical analgesics and/or anaesthetic; Cough, cold and allergy remedies; Antihistamines and/or allergy remedies; and combinations thereof. Vitamins and dietary supplements include, but are not limited to vitamins, dietary

supplements, tonics/bottled nutritive drinks, child-specific vitamins, dietary supplements, any other products of or relating to or providing nutrition, and combinations thereof. Topical analgesics and/or anaesthetic include any topical creams/ointments/gels used to alleviate superficial or deep-seated aches and pains, e.g. muscle pain; teething gel; patches with analgesic ingredient; and combinations thereof. Cough, cold and allergy remedies include, but are not limited to decongestants, cough remedies, pharyngeal preparations, medicated confectionery, antihistamines and child-specific cough, cold and allergy remedies; and combination products. Antihistamines and/or allergy remedies include, but are not limited to any systemic treatments for hay fever, nasal allergies, insect bites and stings. Examples of oral hygiene product include, but are not limited to mouth cleaning strips, toothpaste, toothbrushes, mouthwashes/dental rinses, denture care, mouth fresheners at-home teeth whiteners and dental floss.

In another embodiment, the present compounds can be added to food or beverage products or formulations. Examples of food and beverage products or formulations include, but are not limited to coatings, frostings, or glazes for comestible products or any entity included in the Soup category, the Dried Processed Food category, the Beverage category, the Ready Meal category, the Canned or Preserved Food category, the Frozen Processed Food category, the Chilled Processed Food category, the Snack Food category, the Baked Goods category, the Confectionary category, the Dairy Product category, the Ice Cream category, the Meal Replacement category, the Pasta and Noodle category, and the Sauces, Dressings, Condiments category, the Baby Food category, and/or the Spreads category.

In another embodiment, the present compounds can be added to compositions comprising vegetable and/or non-vegetable proteins. As used herein, the term "non- vegetable protein(s)" means any protein(s), with the exception of vegetable proteins.

Examples of non- vegetable proteins include, but are not limited to proteins derived from milk (e.g., whey proteins, isolates and other dairy hydrolysates such as milk casein hydrolysates). As used herein, the term "vegetable proteins" means any plant and vegetable protein(s) including, without limitation, proteins from grains (e.g., wheat, corn, barley, oats, rye, millet, and buckwheat); proteins from nuts (e.g., walnuts, cashews, almonds, pecans); proteins from seeds (e.g., sunflower, pumpkin, hemp, and flax); proteins from legumes (e.g., beans, lentils, and garbanzos (chickpeas)); and proteins from rice and pea isolates.

In general, the Soup category refers to canned/preserved, dehydrated, instant, chilled, UHT and frozen soup. For the purpose of this definition soup(s) means a food prepared from meat, poultry, fish, vegetables, grains, fruit and other ingredients, cooked in a liquid which may include visible pieces of some or all of these ingredients. It may be clear (as a broth) or thick (as a chowder), smooth, pureed or chunky, ready-to-serve, semi-condensed or condensed and may be served hot or cold, as a first course or as the main course of a meal or as a between meal snack (sipped like a beverage). Soup may be used as an ingredient for preparing other meal components and may range from broths (consomme) to sauces (cream or cheese-based soups).

"Dehydrated and Culinary Food Category" usually means: (i) Cooking aid products such as: powders, granules, pastes, concentrated liquid products, including concentrated bouillon, bouillon and bouillon like products in pressed cubes, tablets or powder or granulated form, which are sold separately as a finished product or as an ingredient within a product, sauces and recipe mixes (regardless of technology); (ii) Meal solutions products such as: dehydrated and freeze dried soups, including dehydrated soup mixes, dehydrated instant soups, dehydrated ready-to-cook soups, dehydrated or ambient preparations of ready-made dishes, meals and single serve entrees including pasta, potato and rice dishes; and (iii) Meal embellishment products such as: condiments, marinades, salad dressings, salad toppings, dips, breading, batter mixes, shelf stable spreads, barbecue sauces, liquid recipe mixes, concentrates, sauces or sauce mixes, including recipe mixes for salad, sold as a finished product or as an ingredient within a product, whether dehydrated, liquid or frozen.

The Beverage category usually means beverages, beverage mixes and concentrates, including but not limited to, carbonated and non-carbonated beverages, alcoholic and non-alcoholic beverages, ready to drink beverages, liquid concentrate formulations for preparing beverages such as sodas, and dry powdered beverage precursor mixes. The Beverage category also includes the alcoholic drinks, the soft drinks, sports drinks, isotonic beverages, and hot drinks. The alcoholic drinks include, but are not limited to beer, cider/perry, FABs, wine, and spirits. The soft drinks include, but are not limited to carbonates, sucha as colas and non-cola carbonates; fruit juice, such as juice, nectars, juice drinks and fruit flavoured drinks; bottled water, which includes sparkling water, spring water and purified/table water; functional drinks, which can be carbonated or still and include sport, energy or elixir drinks; concentrates, such as liquid and powder concentrates in ready to drink measure. The hot drinks include, but are not limited to coffee, such as fresh, instant, and combined coffee; tea, such as black, green, white, oolong, and flavored tea; and other hot drinks including flavour-, malt- or plant-based powders, granules, blocks or tablets mixed with milk or water.

The Snack Food category generally refers to any food that can be a light informal meal including, but not limited to, snacks and snack bars. Examples of snacke food include, but are not limited to fruit snacks, chips/crisps, extruded snacks, tortilla/corn chips, popcorn, pretzels, nuts and other snacks. Examples of snack bars include, but are not limited to granola/muesli bars, breakfast bars, energy bars, fruit bars and other snack bars.

The Baked Goods category generally refers to any edible product the process of preparing which involves exposure to heat or excessive sunlight. Examples of baked goods include, but are not limited to bread, buns, cookies, muffins, cereal, toaster pastries, pastries, waffles, tortillas, biscuits, pies, bagels, tarts, quiches, cake, any baked foods, and any combination thereof. The Ice Cream category generally refers to frozen dessert containing cream and sugar and flavoring. Examples of ice cream include, but are not limited to: impulse ice cream; take-home ice cream; frozen yoghurt and artisanal ice cream; oat, bean (e.g., red bean and mung bean), and rice-based ice creams.

The Confectionary category generally refers to edible product that is sweet to the taste. Examples of confectionary include, but are not limited to candies, gelatins, chocolate confectionery, sugar confectionery, gum, and the likes and any combination products.

The Meal Replacement category generally refers to any food intended to replace the normal meals, particularly for people having health or fitness concerns. Examples of meal replacement include, but are not limited to slimming products and convalescence products. The Ready Meal category generally refers to any food that can be served as meal without extensive preparation or processing. The ready meal includes products that have had recipe "skills" added to them by the manufacturer, resulting in a high degree of readiness, completion and convenience. Examples of ready meal include, but are not limited to canned/preserved, frozen, dried, chilled ready meals; dinner mixes; frozen pizza; chilled pizza; and prepared salads.

The Pasta and Noodle category includes any pastas and/or noodles including, but not limited to canned, dried and chilled/fresh pasta; and plain, instant, chilled, frozen and snack noodles.

The Canned/Preserved Food category includes, but is not limited to canned/preserved meat and meat products, fish/seafood, vegetables, tomatoes, beans, fruit, ready meals, soup, pasta, and other canned/preserved foods.

The Frozen Processed Food category includes, but is not limited to frozen processed red meat, processed poultry, processed fish/seafood, processed vegetables, meat substitutes, processed potatoes, bakery products, desserts, ready meals, pizza, soup, noodles, and other frozen food.

The Dried Processed Food category includes, but is not limited to rice, dessert mixes, dried ready meals, dehydrated soup, instant soup, dried pasta, plain noodles, and instant noodles.

The Chill Processed Food categroy includes, but is not limited to chilled processed meats, processed fish/seafood products, lunch kits, fresh cut fruits, ready meals, pizza, prepared salads, soup, fresh pasta and noodles.

The Sauces, Dressings and Condiments category includes, but is not limited to tomato pastes and purees, bouillon/stock cubes, herbs and spices, monosodium glutamate (MSG), table sauces, based sauces, pasta sauces, wet/cooking sauces, dry sauces/powder mixes, ketchup, mayonnaise, mustard, salad dressings, vinaigrettes, dips, pickled products, and other sauces, dressings and condiments.

The Baby Food category includes, but is note limited to milk- or bean-based formula; and prepared, dried and other baby food.

The Spreads category includes, but is not limited to jams and preserves, honey, chocolate spreads, nut based spreads, and yeast based spreads.

The Dairy Product category generally refers to edible product produced from mammal's milk. Examples of dairy product include, but are not limited to drinking milk products, cheese, yoghurt and sour milk drinks, and other dairy products.

Additional examples for comestible composition, particularly food and beverage products or formulations, are provided as follows. Exemplary comestible compositions include one or more confectioneries, chocolate confectionery, tablets, countlines, bagged selflines/softlines, boxed assortments, standard boxed assortments, twist wrapped miniatures, seasonal chocolate, chocolate with toys, alfajores, other chocolate confectionery, mints, standard mints, power mints, boiled sweets, pastilles, gums, jellies and chews, toffees, caramels and nougat, medicated confectionery, lollipops, liquorice, other sugar confectionery, gum, chewing gum, sugarized gum, sugar-free gum, functional gum, bubble gum, bread, packaged/industrial bread, unpackaged/artisanal bread, pastries, cakes, packaged/industrial cakes, unpackaged/artisanal cakes, cookies, chocolate coated biscuits, sandwich biscuits, filled biscuits, savory biscuits and crackers, bread substitutes, breakfast cereals, rte cereals, family breakfast cereals, flakes, muesli, other cereals, children's breakfast cereals, hot cereals, ice cream, impulse ice cream, single portion dairy ice cream, single portion water ice cream, multi-pack dairy ice cream, multi-pack water ice cream, take-home ice cream, take-home dairy ice cream, ice cream desserts, bulk ice cream, take-home water ice cream, frozen yoghurt, artisanal ice cream, dairy products, milk, fresh/pasteurized milk, full fat

fresh/pasteurized milk, semi skimmed fresh/pasteurized milk, long-life/uht milk, full fat long life/uht milk, semi skimmed long life/uht milk, fat- free long life/uht milk, goat milk, condensed/evaporated milk, plain condensed/evaporated milk, flavored, functional and other condensed milk, flavored milk drinks, dairy only flavored milk drinks, flavored milk drinks with fruit juice, milk, sour milk drinks, fermented dairy drinks, coffee whiteners, powder milk, flavored powder milk drinks, cream, cheese, processed cheese, spreadable processed cheese, unspreadable processed cheese, unprocessed cheese, spreadable unprocessed cheese, hard cheese, packaged hard cheese, unpackaged hard cheese, yoghurt, plain/natural yoghurt, flavored yoghurt, fruited yoghurt, probiotic yoghurt, drinking yoghurt, regular drinking yoghurt, probiotic drinking yoghurt, chilled and shelf-stable desserts, dairy-based desserts, -based desserts, chilled snacks, fromage frais and quark, plain fromage frais and quark, flavored fromage frais and quark, savory fromage frais and quark, sweet and savory snacks, fruit snacks, chips/crisps, extruded snacks, tortilla/corn chips, popcorn, pretzels, nuts, other sweet and savory snacks, snack bars, granola bars, breakfast bars, energy bars, fruit bars, other snack bars, meal replacement products, slimming products, convalescence drinks, ready meals, canned ready meals, frozen ready meals, dried ready meals, chilled ready meals, dinner mixes, frozen pizza, chilled pizza, soup, canned soup, dehydrated soup, instant soup, chilled soup, hot soup, frozen soup, pasta, canned pasta, dried pasta, chilled/fresh pasta, noodles, plain noodles, instant noodles, cups/bowl instant noodles, pouch instant noodles, chilled noodles, snack noodles, canned food, canned meat and meat products, canned fish/seafood, canned vegetables, canned tomatoes, canned beans, canned fruit, canned ready meals, canned soup, canned pasta, other canned foods, frozen food, frozen processed red meat, frozen processed poultry, frozen processed fish/seafood, frozen processed vegetables, frozen meat substitutes, frozen potatoes, oven baked potato chips, other oven baked potato products, non-oven frozen potatoes, frozen bakery products, frozen desserts, frozen ready meals, frozen pizza, frozen soup, frozen noodles, other frozen food, dried food, dessert mixes, dried ready meals, dehydrated soup, instant soup, dried pasta, plain noodles, instant noodles, cups/bowl instant noodles, pouch instant noodles, chilled food, chilled processed meats, chilled fish/seafood products, chilled processed fish, chilled coated fish, chilled smoked fish, chilled lunch kit, chilled ready meals, chilled pizza, chilled soup, chilled/fresh pasta, chilled noodles, oils and fats, olive oil, vegetable and seed oil, cooking fats, butter, margarine, spreadable oils and fats, functional spreadable oils and fats, sauces, dressings and

condiments, tomato pastes and purees, bouillon/stock cubes, stock cubes, gravy granules, liquid stocks and fonds, herbs and spices, fermented sauces, based sauces, pasta sauces, wet sauces, dry sauces/powder mixes, ketchup, mayonnaise, regular mayonnaise, mustard, salad dressings, regular salad dressings, low fat salad dressings, vinaigrettes, dips, pickled products, other sauces, dressings and condiments, baby food, milk formula, standard milk formula, follow-on milk formula, toddler milk formula, hypoallergenic milk formula, prepared baby food, dried baby food, other baby food, spreads, jams and preserves, honey, chocolate spreads, nut-based spreads, and yeast-based spreads. Exemplary comestible compositions also include confectioneries, bakery products, ice creams, dairy products, sweet and savory snacks, snack bars, meal replacement products, ready meals, soups, pastas, noodles, canned foods, frozen foods, dried foods, chilled foods, oils and fats, baby foods, or spreads or a mixture thereof. Exemplary comestible compositions also include breakfast cereals, beverages or solid or liquid concentrate compositions for preparing food and beverages, so as to reduce or alleviate the bitter taste in the food and beverages.

The concentration of the present compound needed to modulate or reduce the bitter flavor of the ingestible composition will of course depend on many variables, including the specific type of the ingestible composition and its various other ingredients, the natural genetic variability and individual preferences and health conditions of various human beings tasting the compositions, and the subjective effect of the particular compound on the taste of such chemosensory compounds.

The present compounds may be used in pharmaceutical compositions as a taste modulator, such as a bitter taste blocker. In other words, the present compounds can be used to modulate the flavor or taste of pharmaceutical compositions. In one embodiment, the pharmaceutical compositions are administered to a patient via the oral route in a dosage form of solid, semi-solid, liquid, or mixtures thereof.

In pharmaceutical compositions, the present compound can be mixed with other ingredients including the therapeutically active ingredient and pharmaceutically acceptable vehicles. One example of a pharmaceutically acceptable vehicle is water. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid vehicles.

Suitable pharmaceutical vehicles also include excipients such as starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol and the like. The present pharmaceutical compositions, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. In addition, auxiliary, stabilizing, thickening, lubricating and coloring agents may be used.

Pharmaceutical compositions comprising a compound of the present invention may be manufactured by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping or lyophilizing processes. Pharmaceutical compositions may be formulated in conventional manner using one or more physiologically acceptable carriers, diluents, excipients or auxiliaries, which facilitate processing of compounds of the present invention into preparations which can be used pharmaceutically. Proper formulation is dependent upon the route of administration chosen. In one

embodiment, the pharmaceutical compostion is a herbal composition, such as the traditional Chinese medicine (TCM). The present pharmaceutical compositions can take the form of solutions, suspensions, emulsion, tablets, pills, pellets, capsules, capsules containing liquids, powders,

sustained-release formulations, aerosols, sprays, suspensions, or any other form suitable for use. In some embodiments, the pharmaceutically acceptable vehicle is a capsule (see e.g., Grosswald et ah, United States Patent No. 5,698,155). Other examples of suitable

pharmaceutical vehicles have been described in the art (see Remington: The Science and Practice of Pharmacy, Philadelphia College of Pharmacy and Science, 20 ^th Edition, 2000).

Pharmaceutical compositions for oral delivery may be in the form of tablets, lozenges, aqueous or oily suspensions, granules, powders, emulsions, capsules, syrups, or elixirs, for example. Orally administered pharmaceutical compositions may contain one or more optionally agents, for example, sweetening agents such as fructose, aspartame or saccharin; flavoring agents such as peppermint, oil of wintergreen, or cherry coloring agents and preserving agents, to provide a pharmaceutically palatable preparation.

For oral liquid preparations such as, for example, suspensions, elixirs and solutions, suitable carriers, excipients or diluents include water, saline, alkyleneglycols {e.g., propylene glycol), polyalkylene glycols {e.g., polyethylene glycol) oils, alcohols, slightly acidic buffers between pH 4 and pH 6 {e.g., acetate, citrate, ascorbate at between about 5.0 mM to about 50.0 mM) etc. Additionally, flavoring agents, preservatives, coloring agents, bile salts, acylcarnitines and the like may be added.

For buccal administration, the pharmaceutical compositions may take the form of tablets, lozenges, etc. formulated in conventional manner.

Liquid drug formulations suitable for use with nebulizers and liquid spray devices and EHD aerosol devices will typically include a compound of the present invention with a pharmaceutically acceptable vehicle. Preferably, the pharmaceutically acceptable vehicle is a liquid such as alcohol, water, polyethylene glycol or a perfluorocarbon. Optionally, another material may be added to alter the aerosol properties of the solution or suspension of compounds of the invention. Preferably, this material is liquid such as an alcohol, glycol, polyglycol or a fatty acid. Other methods of formulating liquid drug solutions or suspension suitable for use in aerosol devices are known to those of skill in the art (see, e.g. , Biesalski, United States Patent No. 5,112,598; Biesalski, United States Patent No. 5,556,611).

Typically at least a bitter flavor/taste modulating amount or a bitter flavor/taste enhancing amount of one or more of the present compound will be added to the ingestible composition so that the bitter flavor modified ingestible composition has a reduced bitter taste as compared to the ingestible composition prepared without the compounds of the present invention, as judged by human beings or animals in general, or in the case of formulations testing, as judged by a majority of a panel of at least eight human taste testers, via procedures commonly known in the field. In one embodiment, for modulating, reducing or alleviating, the bitter taste or other taste properties of other natural or synthetic tastants, and compositions made therefrom, a broad but also low range of concentrations of the compounds or entities of the present invention would typically be required, i.e., from about 0.001 ppm to 100 ppm, or narrower alternative ranges from about 0.1 ppm to about 10 ppm, from about 0.01 ppm to about 30 ppm, from about 0.05 ppm to about 10 ppm, from about 0.01 ppm to about 5 ppm, or from about 0.02 ppm to about 2 ppm, or from about 0.01 ppm to about 1 ppm.

Preparations

Compounds of Formula (I):

In one embodiment, the present invention provides a method of preparing a compound of Formula (I):

or a salt or solvate thereof, in a purified form without chromatographic purification, wherein

1 2 1 1 2 1 2

R , R\ Ar ¹ , A , A X, Y , Y , a, b, and Z are the same as defined above. The compound of

Formula (I) also includes all the subgenus, such as Formua (II), Formula (III), and Formula

(IV), and the species as described above.

The method of preparing the compound of Formula (I) comprises:

mixing a solution of compound of Formula (la) with an aqueous solution of compound of Formula (lb) and a first base at a temperature of about 25°C or lower to form a reaction mixture:

acidifying the reaction mixture to form an acidified reaction mixture; extracting the acidified reaction mixture with a first organic solvent to obtain an organic extract;

washing the organic extract with an aqueous solution of a first acid to obtain a washed organic extract; and

obtaining the compound of Formula (I) in a purified form from the washed organic extract without using chromatographic purification.

In one embodiment of the method of preparing the compound of Formula (I), the mixing step comprises adding a portion of the solution of compound of Formula (la) to the aqueous solution of compound of Formula (lb) and a first base via infusion; and adding the remaining of the solution of compound of Formula (la) to the aqueous solution of compound of Formula (lb) and a first base in bolus.

In one embodiment of the mixing step, the portion is about two third of the solution of compound of Formula (la), and the remaining is about one third of the solution of compound of Formula (la).

In one embodiment, the mixing step is maintained at a temperature of about 20°C or lower, a temperature of about 15°C or lower, a temperature of about 10°C or lower, temperature of about 5°C or lower, a temperature of about 0°C or lower, a temperature of about -5°C or lower, or a temperature of about -10°C or above.

Depending on the amounts and concentrations of the reactants, the reaction mixture obtained from the mixing step is maintained at the temperature of about 25°C or lower for about 15 minutes to about 180 minutes, about 30 minutes to about 120 minutes, about 45 minutes to about 90 minutes, or about 60 minutes.

In the mixing step, the solvent for the solution of compound of Formula (la) can be any organic solvent or mixtures of organic solvents. In one embodiment, the solvent is an aprotic organic solvent miscible with water or an aqueous solution, such as dioxane.

In one embodiment of the method of preparing the compound of Formula (I), the obtaining step comprises removing the first organic solvent from the washed organic extract to obtain a first crude material of compound of Formula (I); and purifying the first crude material of compound of Formula (I) without using chromatographic purification to obtain the compound of Formula (I) in a purified form.

In one embodiment, the purifying step comprises crystallizing or recrystallizing the first crude material of compound of Formula (I).

In another embodiment, the purifying step comprises dissolving the first crude material of compound of Formula (I) in a second organic solvent to obtain an organic solution;

adding an aqueous solution of a second base to the organic solution and removing the second organic solvent to obtain an aqueous suspension;

washing the aquesous suspension with a third organic solvent to obtain a washed aqueous suspension;

acidifying the washed aqueous suspension to obtain an acidified aqueous suspension; extracting the acidified aqueous suspension with a fourth organic solvent to obtain a second organic extract; and

obtaining the compound of Formula (I) in a purified form from the second organic extract without using chromatographic purification. In one embodiment, the obtaining step comprises removing the fourth organic solvent from the second organic extract to obtain a second crude material of compound of Formula (I); and purifying the second crude material of compound of Formula (I) without using chromatographic purification to obtain the compound of Formula (I) in a purified form. In one embodiment, the purification of the second crude material of compound of Formula (I) is carried out by crystallizing or recrystallizing the second crude material of compound of Formula (I).

In the method of preparing the compound of Formula (I), the first and second bases can be the same or different. In one embodiment, the first and second bases are

independently any inorganic base, examples of which include, but are limited to, sodium hydroxide, sodium carbonate, sodium hydrocarbonate, potasium hydroxide, potasium carbonate, potasium hydrocarbonate, and combinations thereof.

In the method of preparing the compound of Formula (I), the acids used for acidification or washing the organic extract can be the same or different. In one embodiment, the acids are independently any inorganic acid, examples of which include, but are limited to, hydrochloride, sulfuric acid, nitric acid, and combinations thereof.

In the method of preparing the compound of Formula (I), the first, second, third, and fourth organic solvents can be the same or different. In one embodiment, the first, second, third, and fourth organic solvents are independently aprotic solvents immiscible with water, the examples of which include, but are not limited to, diethyl ether, ethyl acetate,

dichloromethane, chloroform, and combinations thereof.

In one embodiment, the compound of Formula (la) is prepared by mixing a compound of Formula (Ic) Ar ¹ ^ ^OH _wl th thionyl chloride in the absence of a solvent to form a reaction mixture; and obtaining the compound of Formula (la) without purifying the reaction mixture.

Compounds of Formula (Ic):

In another embodiment, the present invention provides a method of preparing a compound of Formula (Ic):

or a solvate thereof, in a purified form without chromatographic purification,

wherein:

R ¹ is hydrogen, alkyl, or substituted alkyl;

M is an alkali metal when n is 1; or M is an alkaline earth metal when n is 2;

Ar ¹ is aryl, substituted aryl, heteroaryl, or substituted heteroaryl;

A ¹ is alkyl, substituted alkyl, heteroalkyl, substituted heteroalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl, or substituted cycloheteroalkyl;

A ² is a covalent bond, Ci to C ₃ alkylene, substituted Ci to C ₃ alkylene, -C(0)OCR ³ R ⁴ -

, or -C(0)NHCR ³ R ⁴ -;

X is a covalent bond, S, O, CH ₂ , NR ³ , -S(O)-, -S(0) ₂ -, -C(O)-, or -C(S)-;

Y ¹ and Y ² are independently Ci to C ₃ alkylene or substituted Ci to C ₃ alkylene;

a and b are independently 0 or 1, but are not both 0;

Z is -S(O)-, -S(0) ₂ -, -C(O)-, or -C(S)-; and

R ³ and R ⁴ are independently hydrogen, alkyl or substituted alkyl; or R ³ and R ⁴ together with the atoms to which they are bonded, form a cycloheteroalkyl or substituted cycloheteroalkyl ring.

In one embodiment of structural Formula (Ic), Z is -S(0) ₂ - or -C(O)-.

In one embodiment of structural Formula (Ic), A ² is a covalent bond; and M is an alkali metal when n is 1.

In one embodiment of structural Formula (Ic), A ² is Ci to C ₃ alkylene; and M is an alkali metal when n is 1.

In one embodiment of structural Formula (Ic), A ² is -C(0)NHCR ³ R ⁴ -; and M is an alkali metal when n is 1. In one embodiment of structural Formula (Ic), Ar ¹ is monocyclic aryl, substituted monocyclic aryl, monocyclic heteroaryl, substituted monocyclic heteroaryl, fused-bicyclic aryl, substituted fused-bicyclic aryl, fused-bicyclic heteroaryl, or substituted fused-bicyclic heteroaryl. Examples of Ar ¹ include, but are not limited to, phenyl, substituted phenyl, naphthyl, substituted naphthyl, furanyl, substituted furanyl, benzofuran, substituted benzofuran, indole, substituted indole, benzothiophene, substituted benzothiophene, benzooxazole, substituted benzooxazole, pyrazolopyridine, substituted pyrazolopyridine, dihydrobenzofuran, substituted dihydrobenzofuran, thienopyridine, substituted

thienopyridine, thienopyrazole, substituted thienopyrazole, thienopyrazine, substituted thienopyrazine, chromen-2-one, substituted chromen-2-one, quinolin-2-one, and substituted quinolin-2-one.

In one embodiment of structural Formula (Ic), A ¹ is alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, monocyclic aryl, substituted monocyclic aryl, monocyclic heteroaryl, substituted monocyclic heteroaryl, fused-bicyclic aryl, substituted fused-bicyclic aryl, fused-bicyclic heteroaryl, or substituted fused-bicyclic heteroaryl.

In one embodiment of structural Formula (Ic), A ¹ is selected from the group consisting of Ci to C ₆ alkyl, substituted Ci to C ₆ alkyl, C ₃ to C ₇ cycloalkyl, substituted C ₃ to C ₇ cycloalkyl, phenyl, substituted phenyl, naphthyl, substituted naphthyl, furanyl, substituted furanyl, benzofuran, substituted benzofuran, indole, substituted indole, benzothiophene, substituted benzothiophene, benzooxazole, substituted benzooxazole, pyrazolopyridine, substituted pyrazolopyridine, dihydrobenzofuran, substituted dihydrobenzofuran, thienopyridine, substituted thienopyridine, thienopyrazole, substituted thienopyrazole, thienopyrazine, substituted thienopyrazine, chromen-2-one, substituted chromen-2-one, quinolin-2-one, and substituted quinolin-2-one.

In one embodiment of structural Formula (Ic), Y ¹ and Y ² are independently Ci to C ₃ alkylene or substituted Ci to C ₃ alkylene; a and b are 1; and X is S, O, CH ₂ ,NR ³ , -S(O)-, - S(0) ₂ -, -C(O)-, or -C(S)-.

In one embodiment of structural Formula (Ic), Y ¹ is Ci to C ₃ alkylene or substituted Ci to C ₃ alkylene; a is 1; b is 0; and X is a covalent bond.

In one embodiment of the present invention, the compound of structural Formula (Ic) has a structural Formula (He):

or a solvate thereof, wherein:

Ar ¹ and Ar ² are independently aryl, substituted aryl, heteroaryl, or substituted heteroaryl; X is a covalent bond; and a and b are independently 0 or 1, but are not both 0.

In one embodiment of the present invention, the compound of structural Formula (Ic) has a structural Formula (IIIc):

or a solvate thereof, wherein:

Ar ¹ and Ar ² are independently aryl, substituted aryl, heteroaryl, or substituted heteroaryl; and X is S, O, CH ₂ , or NR ³ .

In one embodiment of the present invention, the compound of structural Formula (Ic) has a structural Formula (IVc):

or a solvate thereof, wherein:

Ar ¹ and Ar ² are independently aryl, substituted aryl, heteroaryl, or substituted heteroaryl.

In one embodiment of structural Formula (IVc), the compound has a structure of the following: or a mixture thereof. In one embodiment of structural Formula (He), (IIIc), or (IVc), Ar ¹ and Ar ² are independently monocyclic aryl, substituted monocyclic aryl, monocyclic heteroaryl, substituted monocyclic heteroaryl, fused-bicyclic aryl, substituted fused-bicyclic aryl, fused- bicyclic heteroaryl, or substituted fused-bicyclic heteroaryl.

In one embodiment, M is alkali metal or alkaline earth metal. In one embodiment of

M, the alkali metal is selected from the group consisting of lithium, sodium, potassium, rubidium, caesium, and francium. In another embodiment of M, the alkaline earth metal is selected from the group consisting of beryllium, magnesium; calcium, strontium, barium, and radium.

In certain specific embodiments, the compounds of Formula (Ic) include the M salt of the specific compounds described herein. For example, the compounds of Formula (Ic) include the sodium salt of the specific compounds described herein.

The method of preparing a compound of Formula (la) comprises

mixing a solution of compound of Formula (la) with an aqueous solution of compound of Formula (le) and a first base at a temperature of about 25°C or lower to form a first reaction mixture:

acidifying the first reaction mixture to form an acidified reaction mixture;

extracting the acidified reaction mixture with a first organic solvent to obtain a first organic extract;

washing the first organic extract with an aqueous solution of an acid to obtain a washed organic extract;

dissolving the washed organic extract in a second organic solvent and adding an aqeous solution of a second base to form a second reaction mixture;

neutralizing the second reaction mixture to form a neutralized reaction mixture;

extracting the neutralized reaction mixture with a third organic solvent to obtain a second organic extract;

adding an aqueous solution of a base containing M ⁿ⁺ to the second organic extract and removing the third organic solvent to obtain an aqueous suspension; and obtaining the compound of Formula (la) in a purified form from the aqueous suspension without chromatographic purification.

In one embodiment of the method of preparing a compound of Formula (la), the mixing step comprises adding a portion of the solution of compound of Formula (la) to the aqueous solution of compound of Formula (le) and a first base via infusion; and adding the remaining of the solution of compound of Formula (la) to the aqueous solution of compound of Formula (le) and a first base in bolus. In one embodiment, the portion is about two third of the solution of compound of Formula (la), and the remaining is about one third of the solution of compound of Formula (la).

In one embodiment, the mixing step is maintained at a temperature of about 20°C or lower, a temperature of about 15°C or lower, a temperature of about 10°C or lower, temperature of about 5°C or lower, a temperature of about 0°C or lower, a temperature of about -5°C or lower, or a temperature of about -10°C or above.

Depending on the amounts and concentrations of the reactants, the reaction mixture obtained from the mixing step is maintained at the temperature of about 25°C or lower for about 15 minutes to about 180 minutes, about 30 minutes to about 120 minutes, about 45 minutes to about 90 minutes, or about 60 minutes.

In one embodiment, the second organic extract is washed and concentrated prior to the adding step.

In one embodiment, the obtaining step comprises collecting the compound of Formula

(la) in a crude form from the aqueous suspension; mixing the crude form of the compound of Formula (la) with a fourth organic solvent to form an organic suspension; and collecting the compound of Formula (la) in a purified form from the organic suspension. In one embodiment, each of the collecting steps independently comprises filtering and washing.

In the method of preparing the compound of Formula (Ic), the first and second bases can be the same or different. In one embodiment, the first and second bases are

independently any inorganic base, examples of which include, but are limited to, sodium hydroxide, sodium carbonate, sodium hydrocarbonate, potasium hydroxide, potasium carbonate, potasium hydrocarbonate, and combinations thereof.

In one embodiment, the base containing M ⁿ⁺ has the counter ion selected from the group consisting of hydroxide, hydrocarbonate, carbonate, and a combination thereof. For example, the base can be sodium carbonate.

In the method of preparing the compound of Formula (Ic), the acids used for acidification or washing the organic extracts can be the same or different. In one embodiment, the acids are independently any inorganic acid, examples of which include, but are limited to, hydrochloride, sulfuric acid, nitric acid, and combinations thereof.

In the method of preparing the compound of Formula (Ic), each of the organic solvents, including the first, second, and third organic solvents, can be the same or different. In one embodiment, the first, second, and third organic solvents are independently aprotic solvents immiscible with water, the examples of which include, but are not limited to, diethyl ether, ethyl acetate, dichloromethane, chloroform, and combinations thereof.

In one embodiment, the compound of Formula (la) is prepared by mixing a compound of Formula (Ic) Ar OH _w th thionyl chloride in the absence of a solvent to form a reaction mixture; and obtaining the compound of Formula (la) without purifying the reaction mixture.

The starting materials used in preparing the compounds of the invention, i.e. the various structural subclasses and species of the compounds of the synthetic precursors of the present compounds of Formula (I), are often known compounds, or can be synthesized by known methods described in the literature, or are commercially available from various sources well known to those of ordinary skill in the art, such as for example, Sigma- Aldrich Corporation of St. Louis, Missouri USA and their subsidiaries Fluka and Riedel-de Haen, at their various other worldwide offices, and other well known chemical suppliers such as Fisher Scientific, TCI America of Philadelphia, PA, ChemDiv of San Diego, CA,

Chembridge of San Diego, CA, Asinex of Moscow, Russia, SPECS/BIOSPECS of the Netherlands, Maybridge of Cornwall, England, Acros, TimTec of Russia, Comgenex of South San Francisco, CA, and ASDI Biosciences of Newark, DE.

It is recognized that the skilled artisan in the art of organic chemistry can readily carry out the synthesis of many starting materials and subsequent manipulations without further direction, that is, it is well within the scope and practice of the skilled artisan to carry out many desired manipulations. These include reduction of carbonyl compounds to their corresponding alcohols, oxidations, acylations, aromatic substitutions, both electrophilic and nucleophilic, etherifications, esterification, saponification, nitrations, hydrogenations, reductive animation and the like. These manipulations are discussed in standard texts such as March's Advanced Organic Chemistry (3d Edition, 1985, Wiley-Interscience, New York), Feiser and Feiser's Reagents for Organic Synthesis, and in the various volumes and editions oiMethoden der Organischen Chemie (Houben-Weyl), and the like. Many general methods for preparation of starting materials comprising variously substituted heterocyclic, hetereoaryl, and aryl rings (the precursors of Ar, hAr ¹ , and/or fiAr ² ) can be found in

Methoden der Organischen Chemie (Houben-Weyl), whose various volumes and editions are available from Georg Thieme Verlag, Stuttgart. The entire disclosures of the treatises recited above are hereby incorporated by reference in their entirieties for their teachings regarding methods for synthesizing organic compounds and their precursors.

The skilled artisan will also readily appreciate that certain reactions are best carried out when other functionality is masked or protected in the molecule, thus avoiding any undesirable side reactions and/or increasing the yield of the reaction. Often the skilled artisan utilizes protecting groups to accomplish such increased yields or to avoid the undesired reactions. These reactions are found in the literature and are also well within the scope of the skilled artisan. Examples of many of these manipulations can be found for example in T. Greene and P. Wuts, Protecting Groups in Organic Synthesis, 3 ^r Ed., John Wiley & Sons (1999).

Some exemplary synthetic methods for preparing the present compounds are illustrated in the Schemes 1 to 4 below.

Scheme 1:

As shown in Scheme 1 , compounds IV can be prepared starting by the conversion of carboxylic acids I to the acid chlorides II. Subsequently, II can be coupled, under basic conditions, with various amino acids III to yield IV, directly, or the corresponding ester intermediate which can be hydro lyzed to give IV. Alternatively, a direct condensation of I with III in the presence of a variety of well known amide coupling reagents can also yield IV, directly, or the corresponding ester intermediate followed by hydrolysis of to give IV.

Scheme 2: 1) Pd catalyzed

coupling R ⁴ R ⁵

2) Ol-r, for R ⁴ = 2) OH ^" , for R ⁴ = OR'

IVa: R ⁵ = Br IVe: R ⁵ = B' IVb: R ⁵ = OH

^] Tf ₂ 0, Base OR' IVc: R ⁵ = OTf

As shown in Scheme 2, aryl halides IVa and IVd as well as the aryl triflate IVc can be submitted to appropriate palladium catalyzed "Suzuki" coupling reactions with various organic boronic acids and boronic esters to yield compounds IVe and byaryls IVf,

respectively, (see DeVasher, Rebecca B.; Moore, Lucas R.; Shaughnessy, Kevin H. J. Org. Chem. (2004), 69(23), 7919-7927. Alternatively, compounds IVe and IVf may be prepared by "Suzuki" coupling of IVg and IVh with various aryl halides and aryl Inflates. (Gong, Yong; Barbay, J. Kent; Dyatkin, Alexey B.; Miskowski, Tamara A.; Kimball, Edward S.; Prouty, Stephen M.; Fisher, M. Carolyn; Santulli, Rosemary J.; Schneider, Craig R.; Wallace, Nathaniel H.; Ballentine, Scott A.; Hageman, William E.; Masucci, John A.; Maryanoff, Bruce E.; Damiano, Bruce P.; Andrade-Gordon, Patricia; Hlasta, Dennis J.; Hornby, Pamela J.; He, Wei. J. Med. Chem. (2006), 49(11), 3402-3411).

Scheme 3:

V As shown in Scheme 3, coumarins la can be prepared in one step by condensation of various ort/zo-hydroxybenzaldehydes of Formula V with malonic acid VI. (see Kurien, P. N.; Pandya, K. C; Surange, V. R. J. Indian Chem. Soc. (1934), 11 823-6). Alternatively, la can be prepared by condensation of various ort/zo-hydroxybenzaldehydes of Formula V with Meldrum's acid Via. (see Bandgar, B. P.; Uppalla, L. S.; Kurule, D. S. Green Chemistry (1999), 1(5), 243-245). In addition, coumarins la can be prepared in two steps starting with the condensation of ort/zo-hydroxybenzaldehydes of Formula V with dialkyl malonates VIb followed by hydrolysis of the intermediate alkyl 2-oxo-2H-chromene-3-carboxylate. (see Hori, Yuichiro; Ueno, Hideki; Mizukami, Shin; Kikuchi, Kazuya. J. Am. Chem. Soc. (2009), 131(46), 16610-16611).

Scheme 4:

CNH

O

3) H

VII cr

^(CH ₂ ) _a ^/ °-(CH ₂ ) _b ^/Ar2

VIII

As shown in Scheme lc, compound Ilia can be prepared by O-alkylation of the N- protected serine methyl ester VII with various alkyl halides in the presence of base, (see Faul, Margaret M.; Winneroski, Leonard L.; York, Jeremy S.; Reinhard, Matt R.; Hoying, Richard C; Gritton, William H.; Dominianni, Samuel J. Heterocycles (2001), 55(4), 689-704 and Vedejs, Edwin; Naidu, B. N.; Klapars, Artis; Warner, Don L.; Li, Ven-shun; Na, Younghwa; Kohn, Harold. J. Am. Chem. Soc. (2003), 125(51), 15796-15806). Altenatively, Ilia can be prepared by refluxing VII in an acidic methanolic solution.

Examples

Having now generally described the invention, the same will be more readily understood by reference to the following examples, which are provided by way of illustration and are not intended as limiting. It is understood that various modifications and changes can be made to the herein disclosed exemplary embodiments without departing from the spirit and scope of the invention.

Example 1: (S)-3-(benzylo -2-(5-phenylfuran-2-carboxamido)propanoic acid

Method A: (S)-2-amino-3-(benzyloxy)propanoic acid (0.62 g, 3.20 mmol) was dissolved in 10% Na ₂ C0 ₃ aqueous solution (15mL) at 0°C and a solution of 5-phenylfuran-2-carbonyl chloride (Example la) (0.55 g, 2.66 mmol) in dioxane (15mL) was added dropewise at the same temperature. After stirring for 1 hour at 0°C, the reaction mixture was quenched with 2M HC1 solution and extracted with DCM. The organic extract was washed with brine, dried over Na ₂ S0 ₄ and evaporated to give a residue that was purified by chromatography over silica gel using hexanes/ethyl acetate (gradient 2/8 to 0/100) as eluent to furnish the title compound (0.72 g, 1.97 mmol, 74%). 1H NMR (DMSO, 400 MHz): δ 3.86 (m, 2H), 4.55 (pseudoq, J = 12.4 Hz, 2H), 4.73 (m, 1H), 7.13 (d, J = 3.6 Hz, 2H), 7.23-7.44 (m, 7H), 7.49 (t, 7.6 Hz, 2H), 7.93 (m, 2H), 8.61 (d, J= 8.4 Hz, 1H), 12.95 (brs, 1H). [M+H] ⁺ 366.

Example la: 5-phenylfuran-2-carbonyl chloride

5-phenylfuran-2-carboxylic acid (500 mg, 2.66 mmol) was suspended in dry toluene (5mL) and treated with thionyl chloride (300 mg, ~10 equiv.). The mixture was heated to 80°C for 3 h and volatiles materials were removed under vacuum to yield the desired product as yellow solid which was used in the next step without further purification.

Method B:

Sodium carbonate (21.60 g) in water (216 mL) was cooled down to 0°C and (S)-2- amino-3-(benzyloxy)propanoic acid (SMI) (9.00 g, 46.46 mmol) was added. The mixture was stirred at 0°C until complete dissolution. A solution of 5-phenylfuran-2-carbonyl chloride (Example lb) (8.00 g, 38.70 mmol) in dioxane (216 mL) was added continuously at the same temperature. The final 1/3 of the dioxane solution was added in nearly one portion. After addition was completed, the reaction mixture was stirred vigorously for lh. During that time, a suspension is formed. The reaction was then acidified at 0°C with a 2M aq. HC1 solution and extracted with diethyl ether. The organic extract was washed (x3) with a 2M aq. HC1 solution and concentrated to give a light yellow sticky material. That material was dissolved in diethyl ether (25 mL) and while stirring, a 10%> aq. Na ₂ C0 ₃ solution (200 mL), pre-cooled to 0°C, was added. Stirring continued at 0°C while slowly removing ethyl ether with a flow of nitrogen gas. During that time a white aqueous suspension is formed. After complete dispersion of the organic into the aqueous phase, a nice homogeneous white suspension was observed. Ice water was then added until complete dissolution and the solution was washed with diethyl ether to removed residual colorful organic materials. The aqueous solution was acidified with a 1M aq. HC1 solution, extracted (x3) with diethyl ether, dried over Na ₂ C0 ₃ , filtered and concentrated under reduced pressure. The residue was re- dissolved in ethanol and evaporated under reduced pressure to give (S)-3-(benzyloxy)-2-(5- phenylfuran-2-carboxamido)propanoic acid (12.80 g, 35.03 mmol, 91%). 1H NMR (DMSO, 400 MHz): 53.86 (m, 2H), 4.55 (pseudoq, J= 12.4 Hz, 2H), 4.73 (m, 1H), 7.13 (d, J = 3.6 Hz, 2H), 7.23-7.44 (m, 7H), 7.49 (pseudot, 7.6 Hz, 2H), 7.93 (m, 2H), 8.62 (d, J= 8.4 Hz, 1H), 12.96 (brs, 1H). [MH] ⁺ 366.

Example lb: 5-phenylfuran-2-carbonyl chloride

5-phenylfuran-2-carboxylic acid (15.00 g, 79.71 mmol) was suspended in thionyl chloride (30 mL) and heated at 70°C for 4h. The reaction mixture was dried under vacuum at 60°C to give a light green solid in quantitative yield. This material was used in the next step without further purification.

Example 2: (S)-3-(benzylo -2-(3,7-dimethoxy-2-naphthamido)propanoic acid

Prepared as in Example 1 from 3,7-dimethoxy-2-naphthoyl chloride (Example 2a) and (S)-2- amino-3-(benzyloxy)propanoic acid; [M+HJ 410

Example 2a: 3,7-dimethoxy-2-naphthoyl chloride

Prepared as in Example la from 3,7-dimethoxy-2-naphthoic acid (Example 2b).

Example 2b: 3,7-dimethoxy-2-naphthoic acid

3 -hydroxy-7-methoxy-2 -naphthoic acid (1.00 g, 4.58 mmol) was dissolved in anhydrous acetone (lOOmL) and potassium carbonate (4.00 g, 29.8 mmol) was added follow by dimethyl sulfate (1.50 g, 11.9 mmol). The mixture was refluxed for 6 h and cooled own to room temperature. Water (2mL) was added and the mixture was stirred at room temperature for 2 h. Insoluble material were removed by filtration. After removing acetone from the filtrate, the residue was dissolved in DCM and washed with water, dried over MgSC^ and concentrated under vacuum to give a yellow solid that was used in the next step without further

purification.

Compounds described in Table A were prepared as in Example 1 from (S)-2-amino-3- (benzyloxy)propanoic acid and the corresponding acid chlorides. The latter acid chlorides were either commercially available or prepared as in Example la from the corresponding carboxylic acids. Table A:

Example 3: (S)-3-(benzyloxy)-2-(6-methyl-2-oxo-2H-chromene-3- carboxamido)propanoic aci

Prepared as in Example 1 from 6-methyl-2-oxo-2H-chromene-3-carbonyl chloride (Example 3a) and (S)-2-amino-3-(benzyloxy)propanoic acid. 1H NMR (400 MHz, DMSO): 2.40 (s, 3H), 3.77 (dd, J=3.2 Hz, J=9.6 Hz, IH), 3.95 (dd, J=3.2 Hz, J=9.6 Hz, IH), 4.54 (s, 2H), 4.71 (m, IH), 7.33 (m, 5H), 7.47 (d, J=8.4 Hz, IH), 7.60 (dd, J=2.0 Hz, J=8.8 Hz, IH), 7.81 (s, IH), 8.88 (s, IH), 9.37 (d, J=7.2 Hz, IH), 13.12 (br, IH). [M+H] ⁺ 382.

Example 3a: 6-methyl-2-oxo-2H-chromene-3-carbonyl chloride

Prepared as in Example la from 6-methyl-2-oxo-2H-chromene-3-carboxylic acid (Example 3b).

Example 3b: 6-methyl-2-oxo-2H-chromene-3-carboxylic acid

2-Hydroxy-5-methylbenzaldehyde (272 mg, 2 mmol), 2,2-dimethyl-l,3-dioxane-4,6-dione (288 mg, 2 mmol), piperidine (3.4 mg, 0.04 mmol), and acetic acid (2.4 mg, 0.04 mmol) were dissolved in 3 mL ethanol and stirred at room temperature for 20 minutes. The reaction mixture was then refluxed for 2 hours. The mixture was allowed to cool down to room temperature and poured in ice bath for 1 h. The crystallized product was filtered, washed with ethanol and dried under vacuum to give the title compound. The compound was used in the next step without further purification.

Compounds described in Table B were prepared as in Example 1 from (S)-2-amino-3- (benzyloxy)propanoic acid and the corresponding acid chlorides. The starting 2-oxo-2H- chromene-3-carboxylic acids or 2-oxo-l,2-dihydroquinoline-3-carboxylic acids were either commercially available or prepared as in Example 3b.

Table B

Example 4: (S)-3-(benzyloxy)-2-(5-(p-tolyl)furan-2-carboxamido)propanoi c acid

/?-Tolylboronic acid (14 mg, 0.1 mmol), (S)-3-(benzyloxy)-2-(5-bromofuran-2- carboxamido)propanoic acid (Example 4a) (37 mg, 0.1 mmol) were dissolved in DME (lmL). Potassium carbonate (21 mg, 0.15 mmol) was dissolved in water (0.3mL) and added to the reaction mixture. The mixture was purged for 3 minutes with nitrogen gas. The reaction was irradiated using a microwave at 150°C for 5 min. The reaction mixture was filtered and the clear solution obtained was purified using Varian HPLC (10%-95% ACN in H ₂ 0: 25 minute gradient). The combined fractions were concentrated under vacuum to give the title compound (32 mg, 84%). 1H NMR (400 MHz, DMSO): δ 2.35 (s, 3H), 3.85 (m, 2H), 4.58 (s, 2H), 4.71 (m, IH), 7.05 (d, J=3.6 Hz, IH), 7.31 (m, 8H), 7.81 (d, J=8.0 Hz, 2H), 8.56 (d, J=8.4 H¾ IH), 12.93 (br.s, IH). [M+H] ⁺ 380.

Example 4a: (S)-3-(benzyloxy)-2-(5-bromofuran-2-carboxamido)propanoic acid Prepared as in Example 1 from 2-bromofuran-2-carbonyl chloride (Example 4b) and (S)-2- amino-3-(benzyloxy)propanoic acid. [M+H] ⁺ 368.

Example 4b: 5-bromofuran-2-carbonyl chloride

Prepared as in Example la from 5-bromofuran-2-carboxylic acid.

Compounds described in Table C were prepared as in Example 4 from (S)-3-(benzyloxy)-2- (5-bromofuran-2-carboxamido)propanoic acid (Example 4a) and the corresponding aryl boronic acids.

Table C

Example 5: (S)-3-(benzyloxy)-2-(4-(4-cyanophenyl)furan-2-carboxamido)pr opanoic acid

Prepared as in Example 4 from (4-cyanophenyl)boronic acid and (S)-3-(benzyloxy)-2-(4- bromofuran-2-carboxamido)propanoic acid (Example 5a). [M+H] ⁺ 391.

Example 5a: (S)-3-(benzyloxy)-2-(4-bromofuran-2-carboxamido)propanoic acid Prepared as in Example 1 from 4-bromofuran-2-carbonyl chloride (Example 5b) and (S)-2- amino-3-(benzyloxy)propanoic acid. [M+H] ⁺ 368.

Example 5b: 4-bromofuran-2-carbonyl chloride

Prepared as in Example la from 4-bromofuran-2-carboxylic acid (Example 5c).

Example 5c: 4-bromofuran-2-carboxylic acid

4,5-Dibromofuran-2-carboxylic acid (5.5 g, 20.6 mmol) was suspended in water (63mL). Ammonium hydroxide (18mL) was added and the mixture was stirred vigorously at room temperature followed by the addition of Zn powder (1.3 g, 20.6 mmol). The reaction was stirred for 3 h at room temperature, filtered through celite and the clear solution was acidified to pH 2-3 with a 1M HCl solution. The product was extracted using ethyl acetate and the combined organic layer was evaporated under vacuum to give the final product which was used without further purification.

Compounds described in Table D were prepared as Example 5 from (S)-3-(benzyloxy)-2-(4- bromofuran-2-carboxamido)propanoic acid (Example 5 a) and the corresponding aryl boronic acids.

Table D

Example 6: (S)-3-(benzyloxy)-2-(5-butoxybenzofuran-2-carboxamido)propan oic acid

Prepared as in Example 1 from 5-butoxybenzofuran-2-carbonyl chloride (Example 6a) and (S)-2-amino-3-(benzyloxy)propanoic acid. 1H NMR (400 MHz, DMSO): δ 0.95 (t, J=7.6 Hz, 3H), 1.46 (m, 2H), 1.72 (m, 2H), 3.85 (m, 2H), 4.00 (t, J=6.4 Hz, 2H), 4.51 (pseudo-dd, J=3.2 Hz, 12 Hz, 2H), 4.70 (m, 1H), 7.05 (d, J=1.6 Hz, 8.8 Hz, 1H), 7.27 (m, 2H), 7.32 (m, 4H), 7.55 (m, 2H), 8.63 (d, J=8.0 Hz, 1H), 13.00 (br, 1H). [M+H] ⁺ 412

Example 6a: 5-butoxybenzofuran-2-carbonyl chloride

Prepared as in Example la from methyl 5-butoxybenzofuran-2-carboxylic acid (Example 6b).

Example 6b: 5-butoxybenzofuran-2-carboxylic acid

Methyl 5-hydroxybenzofuran-2-carboxylate (Example 6c) (192 mg, 1 mmol) was dissolved in DMF and placed in ice bath. 1-Bromobutane (205 mg, 1.5 mmol) was added, followed by the addition of NaH (60 mg, 60% in mineral oil, 1.5 mmol). The reaction was stirred in ice bath for 5 minutes and was irradiated using the microwave at 165°C for 5 minutes. The mixture was dissolved in ethyl acetate and washed with water and brine. The organic layer was evaporated under vacuum to give a residue that was suspended in 1M aqueous solution of LiOH (6mL) and heated in a capped vial at 70°C for lh. The reaction mixture was cooled down to room temperature and acidified to pH ~3 with 1M HC1 solution. The product was extracted by ethyl acetate and the organic solution was evaporated under vacuum to give the title compound (50 mg). The compound was used in the next step without further

purification.

Example 6c: methyl 5-hydroxybenzofuran-2-carboxylate

5-Hydroxybenzofuran-2-carboxylic acid (Example 6d) (500 mg, 2.8 mmol) was dissolved in DCM (20mL). PS 4-(methylazoamino)phenoxymethyl resin was added and stirred at room temperature for 2 hours. The resin was removed by filtration and the solution was evaporated under vacuum to give the desired methyl ester product in quantitative yield.

Example 6d: 5-hydroxybenzofuran-2-carboxylic acid

Ethyl 5-methoxybenzofuran-2-carboxylate (2.2 g, 10 mmol), was dissolved in 25mL DCM and cooled to -78°C. 1M BBr ₃ in DCM (11 mL, 11 mmol), was added slowly at -78°C. The reaction was allowed to warm up to room temperature and stirred overnight. The reaction mixture was concentrated under vacuum and the residue was dissolved in methanol and purified using Varian HPLC (10%-95% ACN in H ₂ 0: 25 minute gradient) to give 1.3 g of the title compound.

Compounds described in Table E were prepared as in Example 6 from (S)-2-amino-3- (benzyloxy)propanoic acid and the corresponding acid chlorides.

Table E

Example 7: (S)-3-(benzyloxy -2-(7-hydroxybenzofuran-2-carboxamido)propanoic acid

Prepared as in Example 1 from 7-hydroxybenzofuran-2-carbonyl chloride (Example 7a) and (S)-2-amino-3-(benzyloxy)propanoic acid. 1H NMR (400 MHz, DMSO): δ 3.87 (m, 2H), 4.55 (pseudo-dd, J=3.6 Hz, J=12.4 Hz, 2H), 4.73 (m, IH), 6.89 (d, J=7.6 Hz, IH), 7.14 (m, 2H), 7.30 (m, 5H), 7.58 (d, J=0.8 Hz, IH), 8.46 (d, J=8.0 Hz, IH), 10.30 (s, IH), 13.00 (br.s, IH). [M+H] ⁺ 356.

Example 7a: 7-hydroxybenzofuran-2-carbonyl chloride

Prepared as in Example 6a from 7-hydroxybenzofuran-2-carboxylic acid (Example 7b). Example 7b: 7-hydroxybenzofuran-2-carboxylic acid

7-methoxybenzofuran-2-carboxylic acid (725 mg, 5.65 mmol) and pyridine HC1 (1.3 g, 16 mmol) were mixed as solid and heated in oil bath at 200°C for 30 minutes. The crude reaction was diluted with methanol (10 mL) and purified using Varian HPLC (10%-95% ACN in H ₂ 0: 25 minute gradient) to give the title compound (350 mg).

Example 8: S)-3-(benzylox -2-(5-hydroxybenzofuran-2-carboxamido)propanoic acid

Prepared as in Example 1 from 5-hydroxybenzofuran-2-carbonyl chloride (Example 8a) and

(S)-2-amino-3-(benzyloxy)propanoic acid. 1H NMR (400 MHz, DMSO): δ 3.85 (m, 2H), 4.54 (pseudo-dd, J=3.2 Hz, J=12.0 Hz, 2H), 4.70 (m, 1H), 6.92 (dd, J=2.8 Hz, J=8.8 Hz, 1H), 7.04 (dd, J=0.4 Hz, J=2.4 Hz, 1H), 7.28 (m, 1H), 7.32 (m, 4H), 7.48 (m, 2H), 8.57 (d, J=8.0 Hz, 1H), 9.40 (s, 1H), 13.00 (br.s, 1H). [M+H] ⁺ 356.

Example 8a: 5-hydroxybenzofuran-2-carbonyl chloride

Prepared as in Example la from 5-hydroxybenzofuran-2-carboxylic acid (Example 6d). Example 9: (S)-3-(benzyloxy)-2-(5-cyanobenzofuran-2-carboxamido)propano ic acid

Prepared as in Example 1 from 5-cyanobenzofuran-2-carbonyl chloride (Example 9a) and

(S)-2-amino-3-(benzyloxy)propanoic acid. 1H NMR (400 MHz, DMSO): δ 3.86 (m, 2H), 4.53 (pseudo-dd, J=2.8 Hz, J=12.4 Hz, 2H), 4.70 (m, 1H), 7.27 (m, 1H), 7.30 (m, 4H), 7.77 (s, 1H), 7.92 (pseudo-t, J=10.0 Hz, 2H), 8.39 (s, 1H), 8.91 (br.d, J=6.0 Hz, 1H), 13.00 (br.s, 1H). [M+H] ⁺ 365.

Example 9a: 5-cyanobenzofuran-2-carbonyl chloride

Prepared as in Example la from 5-cyanobenzofuran-2-carboxylic acid (Example 9b).

Example 9b: 5-cyanobenzofuran-2-carboxylic acid

5-Bromobenzofuran-2-carboxylic acid (482 mg, 2 mmol) and CuCN (213 mg, 2.4 mmol) were suspended in NMP (lOmL). The reaction was irradiated using a microwave at 200°C for 20 minutes. The reaction mixture was dissolved in ethyl acetate and washed with water and brine. The organic layer was evaporated under vacuum. The product was purified using Varian HPLC (10%-95% ACN in H ₂ 0: 25 minute gradient). The combined fractions were concentrated under vacuum to give the title compound (115 mg).

(S)-methyl 2-(2-amino-3-(benzyloxy)propanamido)acetate (Example 10a) (150 mg, 0.56 mmol) and triethylamine (57 mg, 0.56 mmol) were dissolved in DCM (5mL). 5- methoxybenzofuran-2-carbonyl chloride (example 13b) (118 mg, 0.56 mmol) was added and the mixture was stirred overnight at room temperature. The reaction was concentrated under vacuum, the residue was dissolved in methanol (3mL) and purified by Varian HPLC (10%- 95% ACN in H ₂ 0: 25 minute gradient). The combined fractions were concentrated under vacuum to give the ester intermediate (32 mg, 13%); [M+H] ⁺ 441. The obtained ester intermediate was dissolved in ethanol (lmL) and added to a 1M NaOH solution (2mL). The reaction was heated in a capped vial at 80°C for 1 h. The reaction was washed with ethyl acetate and the aqueous layer was acidified using 1M HC1 to pH ~3. The product was extracted using ethyl acetate and the organic layer was evaporated under vacuum to give the title compound (22 mg, 71%). 1H NMR (400 MHz, DMSO): δ 3.17 (s, 2H), 3.80 (m, 5H), 4.53 (s, 2H), 4.82 (m, 1H), 7.07 (m, 1H), 7.29 (m, 6H), 7.58 (m, 2H), 8.47 (t, J=6.0 Hz, 1H), 8.55 (d, J=8.4 Hz, 1H), 12.70 (br.s, 1H). [M+H] ⁺ 427.

Example 10a: (S)-methyl 2-(2-amino-3-(benzyloxy)propanamido)acetate

(S)-3-(benzyloxy)-2-((tert-butoxycarbonyl)amino)propanoic acid (295 mg, 1 mmol), HOBt (135mg, 1 mmol), EDC (191 mg, 1 mmol), triethylamine (202 mg, 2 mmol) and methyl 2- aminoacetate (89 mg, 1 mmol) were dissolved in 5 mL DMF. The reaction was stirred at room temperature overnight. The crude product was dissolved in ethyl acetate and washed with water and brine. The organic layer was concentrated under vacuum to a residue that was dissolved in 5mL 50% DCM/TFA and let to stir for 30 minutes at room temperature. The reaction was concentrated under vacuum to give the desired product (150 mg) that was used directly for the next step without purification. [M+H] ⁺ 267.

Example 11: (S)-4-(benzyloxy)-3-(5-methoxybenzofuran-2-carboxamido)butan oic acid

(S)-methyl 4-(benzyloxy)-3-(5-methoxybenzofuran-2-carboxamido)butanoate (560 mg) (Example 11a) was dissolved in ethanol and treated with 1M aqueous NaOH solution (5 equiv.) and stirred at room temperature for lh. The mixture was acidified at 0 °C with 1M aqueous HC1 solution extracted with DCM and dried under vacuum to give the desired product as a white solid. 1H NMR (400 MHz, DMSO): δ 2.60 (m, 2H), 3.50 (m, 2H), 3.80 (s, 3H), 4.53 (m, 3H), 7.05 (dd, J=2.4 Hz, J=8.8 Hz, 1H), 7.27 (m, 2H), 7.32 (m, 4H), 7.46 (d, J=0.8 Hz, 1H), 7.55 (dm, J=9.2 Hz, 1H), 8.54 (d, J=8.4 Hz, 1H), 12.24 (br.s, 1H). [M+H] ⁺ 384.

Example 11a: (S)-methyl 4-(benzyloxy)-3-(5-methoxybenzofuran-2- carboxamido)butanoate

Prepared as in Example 1 from 5-methoxybenzofuran-2-carbonyl chloride (Example 13b) and (S)-methyl 3-amino-4-(benzyloxy)butanoate hydrochloride (Example l ib); [M+H] ⁺ 398.

Example l ib: (S)-methyl 3-amino-4-(benzyloxy)butanoate hydrochloride

(S)-methyl 4-(benzyloxy)-3-((tert-butoxycarbonyl)amino)butanoate (1.00 g, 3.23 mmol) was dissolved in anhydrous methanol and treated with 2M ethereal solution of HC1 (20 equiv). The mixture was refluxed for 4h and volatiles were removed under vavuum to give the desired product in quantitative yield.

Example 12: (R)-4-(benzyloxy)-3-(5-methoxybenzofuran-2-carboxamido)butan oic acid

Prepared as in Example 11 from (R)-methyl 4-(benzyloxy)-3-(5-methoxybenzofuran-2- carboxamido)butanoate (Example 12a); [M+H] ⁺ 384. Example 12a: (R)-methyl 4-(benzyloxy)-3-(5-methoxybenzofuran-2- carboxamido)butanoate

Prepared as in Example 1 from 5-methoxybenzofuran-2-carbonyl chloride (Example 13b) and (R)-methyl 3-amino-4-(benzyloxy)butanoate hydrochloride (Example 12b); [M+H] ⁺ 398.

Example 12b: (R)-methyl 3-amino-4-(benzyloxy)butanoate hydrochloride

Prepared as in Example l ib from (R)-methyl 4-(benzyloxy)-3-((tert- butoxycarbonyl)amino)butanoate to give the desire product in quantitative yield.

Example 13: (S)-3-(2'-cyano-[l, l'-biphenyl]-4-yl)-2-(5-methoxybenzofuran-2- carboxamido) propanoic acid

(S)-3-(4-bromophenyl-2-(5-methoxybenzofuran-2-carboxamido) propanoic acid (Example 13a) (0.10 g, 0.24 mmol) was dissolved in dioxane (2mL) and treated with solution of K ₂ C0 ₃ (0.07 g, 0.48 mmol) in H ₂ 0 (0.20 mL) and 2-cyanophenyl boronic acid (0.04 g, 0.25 mmol). N ₂ gas was bubbled into the mixture for 10 minutes and Pd(PPh ₃ ) ₄ (1 mg, 0.5% mole) was added. The vial was sealed and irradiated with microwave for 30 minutes at 150°C. The crude mixture was dissolved in 2N NaOH (lOmL) and washed with ethyl acetate (lOmL). The aqueous layer was then acidified with HCl until pH=2.0 and extracted with ethyl acetate. The organic layer was concentrated down and purified by prep HPLC to give (S)-3-(2'- cayno-[l, l '-biphenyl]-4-yl)-2-(5-methoxybenzofuran-2-carboxamido) propanoic acid (28 mg, 27%) as a white solid. 1H NMR (DMSO, 400 MHz): δ 3.21-3.34 (m, 2H), 3.80 (s, 3H), 3.69-4.74 (m, 1H), 7.05 (dd, J=2.8 Hz, J=9.2 Hz, 1H), 7.26 (d, J=2.8 Hz 1H), 7.43-7.59 (m, 8H), 7.75 (dt, J=1.2 Hz, J=7.6 Hz, 1H), 7.92 (dd, J=0.8, J=7.6 Hz, 1H), 8.94 (d, J=8.0 Hz 1H), 12.98 (br.s, 1H). [M+H] ⁺ 411

Example 13a: (S)-3-(4-bromophenyl-2-(5-methoxybenzofuran-2-carboxamido) propanoic acid

Prepared as in Example 1 from (S)-2-amino-3-(4-bromophenyl)propanoic acid (0.36 g, 1.46 mmol) and 5-methoxybenzofuran-2-carbonyl chloride (Example 13b) (0.28 g, 1.46 mmol) to give (S)-3-(4-bromophenyl-2-(5-methoxybenzofuran-2-carboxamido) propanoic acid as a white solid (350 mg, 57%). [M+H] ⁺ 419

Example 13b: 5-methoxybenzofuran-2-carbonyl chloride

Method A:

Prepared as in Example la from 5-methoxybenzofuran-2-carboxylic acid.

Method B:

5-methoxybenzofuran-2-carboxylic acid (8.00 g, 41.63 mmol) was suspended in thionyl chloride (20 mL) and refluxed until a homogeneous solution was obtained (~ 3h). The reaction mixture was dried under vacuum at 60°C to give a yellowish solid in quantitative yield. This material was used in the next step without further purification. Example 14: (S)-3-(3'-hydroxy-[l, l'-biphenyl]-4-yl)-2-(5-methoxybenzofuran-2- carboxamido) propanoic acid

Prepared as in Example 13 from (S)-3-(4-bromophenyl-2-(5-methoxybenzofuran-2- carboxamido) propanoic acid (Example 13 a) and 3-hydroxyphenyl boronic acid to furnish (S)-3-(3'-hydroxy-[l, 1 '-biphenyl]-4-yl)-2-(5-methoxybenzofuran-2-carboxamido) propanoic acid (49 mg, 45%) as a white solid. [M+H] ⁺ 432. Example 15: (S)-3-(2'-hydroxy-[l, l'-biphenyl]-4-yl)-2-(5-methoxybenzofuran-2- carboxamido) propanoic acid

Prepared as in Example 13 from (S)-3-(4-bromophenyl-2-(5-methoxybenzofuran-2- carboxamido) propanoic acid (Example 13 a) and 2-hydroxyphenyl boronic acid to yield (S)- 3-(2'-hydroxy-[l, 1 '-biphenyl]-4-yl)-2-(5-methoxybenzofuran-2-carboxamido) propanoic acid (56 mg, 52%) as a white solid. 1H NMR (DMSO, 400 MHz): δ 3.13-3.26 (m, 2H), 3.79 (s, 3H), 4.63-4.66 (m, IH), 6.82 (dt, J=1.2 Hz, J=7.6 Hz, IH), 6.90 (dd, J=0.8 Hz, J=8.0 Hz, IH), 7.04 (dd, J=2.8 Hz, J=8.8 Hz, IH), 7.11 (dt, J=1.6 Hz, J=8.0 Hz, IH), 7.20 (dd, J=1.6 Hz, J=7.6 Hz, IH), 7.26 (d, J=2.4 Hz, 2H), 7.30 (d, J=8.0 Hz, 2H), 7.44 (d, J=8.0 Hz, IH), 7.50 (d, J=0.8 Hz, IH), 7.58 (d, J=9.2 Hz, IH), 8.85 (d, J=8.0 Hz, IH), 9.47 (s, IH), 13.93 (br.s, IH). [M+H] ⁺ 432.

Example 16: (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(2'-methoxymethy l-[l, 1'- biphenyl]-4-yl)-propanoic acid

Prepared as in Example 13 from (S)-3-(4-bromophenyl-2-(5-methoxybenzofuran-2- carboxamido) propanoic acid (Example 13 a) and 2-(methoxymethyl) phenyl boronic acid to give (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(2'-methoxymethy l-[l, 1 '-biphenyl]-4- yl)- propanoic acid (59 mg, 51%) as a white solid. [M+H] ⁺ 460.

Example 17: (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(3'-(N-methylsul famoyl)- [1, l'-biphenyl]-4-yl)-propanoic acid

Prepared as in Example 13 from (S)-3-(4-bromophenyl-2-(5-methoxybenzofuran-2- carboxamido) propanoic acid (Example 13a) and methyl 3-boronobenzensulfonamide to yield (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(3'-(N-methylsul famoyl)-[l, 1 '- biphenyl]-4-yl)- propanoic acid (55 mg, 45%) as a white solid. 1H NMR (DMSO, 400 MHz) δ 2.40 (br.s, 3H), 3.16-3.32 (m, 2H), 3.79 (s, 3H), 4.10-4.14 (m, IH), 7.01 (dd, J=2.8 Hz, J=9.2 Hz, IH), 7.22-7.26 (m, 3H), 7.40 (d, J=1.2 Hz IH), 7.50-7.55 (m, 4H), 7.64 (m, IH), 7.70 (dt, J=1.6 Hz, J=8.0 Hz, IH), 7.89 (dt, J=1.6 Hz, J=8.0 Hz, IH), 7.95 (t, J=1.6 Hz, IH), 7.99 (d, J=6.0 Hz, IH). [M+H] ⁺ 509.

Example 18 : (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(naphthalene-2-y l)- propanoic acid

Prepared as in Example 1 from (S)-2-amino-3-(naphthalen-2-yl)propanoic acid and (Example 13b) to give (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(naphthalene-2-y l)-propanoic acid (280 mg, 62%) as a brown solid. [M+H] ⁺ 390.

Compounds described in Table F were prepared as in Example 13 from (S)-3-(4- bromophenyl-2-(5-methoxybenzofuran-2-carboxamido) propanoic acid (Example 13 a) and the corresponding boronic acids:

Table F

Compound No. Compound [M+H] ⁺

F30

444

(S)-3-(4'-ethyl-[l,r-biphenyl]-4-yl)-2-(5- methoxybenzofuran-2-carboxamido)propanoic acid

F31

432

(S)-3-(4'-hydroxy-[l , l'-biphenyl]-4-yl)-2-(5- methoxybenzofuran-2-carboxamido)propanoic acid

F32

460

(S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(4'- (methoxymethyl)- [ 1 , 1 '-bipheny 1] -4-yl)propanoic

acid

F33

446

(S)-3-(4'-methoxy-[l , l'-biphenyl]-4-yl)-2-(5- methoxybenzofuran-2-carboxamido)propanoic acid

F34

441

(S)-3-(4'-isocyano-[l,r-biphenyl]-4-yl)-2-(5- methoxybenzofuran-2-carboxamido)propanoic acid

Example 19: (S)-3-(2\ 6'-dimethyl-[l, l'biphenyl]-4-yl)-2-(5-methoxybenzofuran-2- carboxamido) propanoic acid

(S)-methyl 3-(2', 6 '-dimethyl- [1,1 'biphenyl]-4-yl)-2-(5-methoxybenzofuran-2- carboxamido)propanoate (Example 19a) (0.05 g, 0.12 mmol) was dissolved in THF (0.8 mL) and MeOH (0.1 mL) and treated with 1M LiOH solution (0.1 mL). The mixture was stirred at room temperature for 2 h. The solution was concentrated. The residue was dissoved in ethyl acetate (5 mL) and washed with water (5 mL) and an aqueous solution of 10% citric acid (5 mL). The organic layer was dried over Na ₂ S0 ₄ , filtered, and dried under vacuum to give(S)- 3-(2', 6'-dimethyl-[l, 1 'biphenyl]-4-yl)-2-(5-methoxybenzofuran-2-carboxamido)propan oic acid (35 mg, 67%) as a white solid; [M+H] ⁺ 444.

Example 19a: (S)-methyl 3-(2', 6'-dimethyl-[l, 1 'biphenyl]-4-yl)-2-(5- methoxybenzofuran-2-carboxamido) propanoate

(S)-methyl-2-(5-methoxybenzofuran-2-carboxamido)-3-(4-

(((trifluoromethyl)sulfonyl)oxy)phenyl) propanoate (Example 19b) (0.11 g, 0.22 mmol) and 2,6 dimethylphenyl boronic acid (0.10 g, 0.66 mmol) were dissolved in DME (2.5 mL) and treated with a solution of K ₂ C0 ₃ (0.17 g, 1.21 mmol) in H ₂ 0 (0.5 mL). N ₂ gas was bubbled into the mixture for 10 minutes followed by addition of Pd(PPh ₃ ) ₄ (0.14 g, 0.12 mmol ) and the mixture was heated for 24 h at 80°C. The mixture was cooled down to room temperature, diluted with H ₂ 0 (10 mL) and extracted with ethyl acetate (15 mL). The organic layer was dried over Na ₂ S0 ₄ , filtered, and concentrated. The crude product was isolated by column chromatography using hexane/ethyl acetate as eluent. The fractions containing the desired product were then purified by prep HPLC to give(S)-methyl 3-(2', 6'-dimethyl-[l, l 'biphenyl]-4-yl)-2-(5-methoxybenzofuran-2-carboxamido)propan oate (54 mg, 54%) as a white solid.

Example 19b: (S)-methyl-2-(5-methoxybenzofuran-2-carboxamido)-3-(4- (((trifluoromethyl) sulfonyl)oxy)phenyl) propanoate

Pyridine (0.33 mL, 4.06 mmol) was added to a solution of (S)-methyl-3-(4-hydroxyphenyl)- 2-(5-methoxybenzofuran-2-carboxamido) propanoate (Example 19c- JF) (0.50 mg, 1.35 mmol) in DCM (12 mL) under N ₂ . The mixture was cooled down to 0°C by an ice bath and triflic anhydride (0.27 mL, 1.62 mmol) was added dropwise with stirring. After addition, the solution was stirred at room temperature for 3 hours. The solution was dissolved in DCM (20 mL) and washed with water (15 mL), IN HC1 (15 mL), and brine(15 mL). The organic layer was then washed with aqueous saturated bicarbonate (15 mL) and water (15 mL), dried over Na ₂ S0 ₄ , filtered, and concentrated down. The crude product was isolated by column chromatography using DCM/MeOH as eluent to give (S)-methyl-2-(5-methoxybenzofuran-2- carboxamido)-3-(4-(((trif uoromethyl)sulfonyl)oxy)phenyl) propanoate (0.55 g, 81%) as an oil. [M+H] ⁺ 502.

Example 19c: (S)-methyl-3-(4-hydroxyphenyl)-2-(5-methoxybenzofuran-2- carboxamido) propanoate

(S)-methyl 2-amino-3-(4-hydroxyphenyl)propanoate (0.99 g, 5.08 mmol) was added to a solution of Na ₂ C03 (1.62 g, 15.24 mmol) in H ₂ 0 (7 mL) and stirred until the solution became homogeneous. 5-Methoxybenzofuran-2-carbonyl chloride (Example 13b) (0.98 g, 5.08 mmol) in dioxane (7 mL) was then added. The mixture was stirred at room temperature for 16 h. The solution was diluted with H ₂ 0 (20 mL) and extracted with ethyl acetate. The combined organic layers were dried over Na ₂ S0 ₄ , filtered and concentrated down to give (S)- methyl-3-(4-hydroxyphenyl)-2-(5-methoxybenzofuran-2-carboxam ido) propanoate (1.29 g, 95%) as a solid; [M+H] ⁺ 370.

Compounds described in Table G were prepared as in Example 19 from the corresponding esters which were obtained as in Example 19a from (S)-methyl 2-(5-methoxybenzofuran-2- carboxamido)-3-(4-(((trifluoromethyl)sulfonyl)oxy)phenyl)pro panoate (Example 19b) and the appropriate boronic acids:

Table G

Compound No. Compound [M+H] ⁺

G2

476

(S)-3-(2 6 ^, -dimethoxy-[l ,l ^, -biphenyl]-4-yl)-2-(5- methoxybenzofuran-2-carboxamido)propanoic acid

Example 20: (S)-2(5-methoxybenzofuran-2-carboxamido) 3-(4-(pyridine-2-yl)phenyl) propanoic acid

(S)-3-(4-bromophenyl-2-(5-methoxybenzofuran-2-carboxamido ) propanoic acid (Example 13a) (0.15 g, 0.36 mmol) was added to a solution of CS ₂ CO ₃ (0.23 g, 0.72 mmol), dppf (0.02 g, 0.04 mmol), CuBr (0.05 g, 0.36 mmol), pyridine-2-boronic acid pinacol ester (0.18 g, 0.90 mmol) , and Pd(OAc) ₂ (0.01 g, 0.02 mmol) in DMF (4 mL). The vial was purged with nitrogen, sealed and the mixture was heated to 100°C for 16 h. The solution was filtered over a pad of celite and washed several time with ethyl acetate. The filtrate was dissolved with IN HC1 (20 mL). The aqueous layer was extracted and washed with a solution of DCM/IPA (3 : 1). The combined organic layers were dried over Na ₂ S0 ₄ , filtered, and concentrated down. The crude product was then purified by prep HPLC to give (S)-2(5-methoxybenzofuran-2- carboxamido) 3-(4-(pyridine-2-yl)phenyl) propanoic acid (13 mg, 9%) as a white solid;

[M+H] ⁺ 417.

Example 21: (R)-3-(benzylthio)-2-(5-methoxybenzofuran-2-carboxamido)prop anoic acid

To 5-methoxybenzofuran-2-carbonyl chloride (769 mg, 3.65 mmol) (Example 13b) in tetrahydrofuran (50 mL) at room temperature was added (R)-2-amino-3- (benzylthio)propanoic acid (771 mg, 3.65 mmol) and triethylamine (0.607 mL, 4.38 mmol). The reaction was stirred at room temperature for 16 hours. The crude reaction mixture was concentrated on the rotovap. The residue was dissolved in dichloromethane and washed consecutively with brine, 0.1 M HC1, and water. The organics were dried over sodium sulfate, filtered and concentrated on the rotovap. The crude product was purified by silica gel chromatography (methanol/dichloromethane gradient). The pure fractions were collected and concentrated on the rotovap. The crude solid was recrystallized from ethanol affording (R)-3- (benzylthio)-2-(5-methoxybenzofuran-2-carboxamido)propanoic acid (502 mg, 36%) as a white solid. 1H NMR (DMSO, 400 MHz): δ 2.84-2.96 (m, 2H), 3.76 (s, 2H), 3.79 (s, 3H), 4.57-4.65 (m, 1H), 7.06 (dd, J= 8.8, 2.8 Hz, 1H), 7.18-7.25 (m, 2H), 7.26 (d, J= 2.8 Hz,

1H), 7.28 (d, J= 1.2 Hz, 2H), 7.30 (s, 1H), 7.53 (d, J= 0.8 Hz, 1H), 7.56 (d, J= 8.8 Hz, 1H), 8.87 (d, J= 8.4 Hz, 1H), 12.98 (s, 1H); [M+H] ⁺ 386.

Example 22: (S)-3-(benzyloxy)-2-(5-methoxybenzofuran-2-carboxamido)propa noic acid

Method A:

To (S)-2-amino-3-(benzyloxy)propanoic acid (255 mg, 1.31 mmol) and sodium carbonate (413 mg, 3.90 mmol) in water (8 mL) and dioxane (3 mL) at room temperature was added 5-methoxybenzofuran-2-carbonyl chloride (275 mg, 1.31 mmol) (Example 13b). The reaction was stirred at room temperature for 1 hour. The crude reaction mixture was acidified with 0.1 M HC1, extracted with EtOAc and purified by HPLC. The pure fractions were concentrated on the rotary evaporator. The white solid was recrystallized from ethanol and to give (S)-3-(benzyloxy)-2-(5-methoxybenzofuran-2-carboxamido)propa noic acid (427mg, 66%) as a white crystalline solid. 1H NMR (DMSO, 400 MHz): δ 3.79 (s, 3H), 3.79-3.89 (m, 2H), 4.52 (d, J= 2.8 Hz, 2H), 4.67-4.72 (m, 1H), 7.05 (dd, J= 8.8, 2.8 Hz, 1H), 7.24-7.31 (m, 6H), 7.55 (d, J= 1.2 Hz 1H), 7.57 (d, J= 8.8 Hz, 1H), 8.62 (d, J= 7.6 Hz, 1H), 12.98 (s, 1H); [M+H] ⁺ 370.

Method B:

Sodium carbonate (23.50 g) in water (235 mL) was cooled down to 0°C and (S)-2- amino-3-(benzyloxy)propanoic acid (9.70 g, 49.70 mmol) was added. The mixture was stirred at 0°C until complete dissolution. A solution of 5-methoxybenzofuran-2-carbonyl chloride (Example 13b) (8.60 g, 41.00 mmol) in dioxane (235 mL) was added continuously at the same temperature. The final 1/3 of the dioxane solution was added in nearly one portion. After addition was completed, the reaction mixture was stirred vigorously for lh. During that time, a suspension is formed. The reaction was then acidified at 0°C with a 2M aq. HC1 solution and extracted with ethyl acetate. The organic extract was washed (x3) with a 2M aq. HC1 solution, dried over Na ₂ C0 ₃ , filtered and concentrated to give a beige solid that was recristallized from ethanol and water affording (S)-3-(benzyloxy)-2-(5-methoxybenzofuran- 2-carboxamido)propanoic acid (13.40 g, 36.28 mmol, 89%) as a white solid. 1H NMR

(DMSO, 400 MHz): δ 3.80 (s, 3H), 3.81-3.92 (m, 2H), 4.54 (d, J = 2.8 Hz, 2H), 4.70-4.75 (m, 1H), 7.07 (dd, J = 8.8, 2.8 Hz, 1H), 7.24-7.33 (m, 6H), 7.56-7.58 (m, 2H), 8.65 (d, J = 8.0 Hz, 1H), 13.01 (s, 1H). [MH] ⁺ 370.

Example 23: (S)-2-(5-methoxybenzofuran-2-carboxamido)-5-phenylpentanoic acid

To (S)-2-amino-5-phenylpentanoic acid (94 mg, 0.489 mmol) and sodium carbonate (156 mg, 1.47 mmol) in water (8 mL) and dioxane (3 mL) at room temperature was added 5- methoxybenzofuran-2-carbonyl chloride (103 mg, 0.489 mmol) (Example 13b-JF). The reaction was stirred at room temperature for 1 hour. The crude reaction mixture was acidified with 0.1 M HC1 and extracted with ethyl acetate (3 X 20 mL). The organics were dried over sodium sulfate, filtered and concentrated on the rotovap. The crude product was purified by biotage Si0 ₂ chromatography followed by RP HPLC. The pure fractions were collected and concentrated on the rotary evaporator. The frozen water was sublimed on the lyophilizer. The white solid was recrystallized from ethanol and water affording (S)-2-(5- methoxybenzofuran-2-carboxamido)-5-phenylpentanoic acid (145 mg, 81%) as a white solid. 1H NMR (DMSO, 400 MHz): δ 1.56-1.72 (m, 2H), 1.75-1.89 (m, 2H), 2.56-2.60 (m, 2H),

3.78 (s, 3H), 4.36-4.42 (m, 1H), 7.04 (dd, J= 9.2, 3.2 Hz, 1H), 7.12-7.18 (m, 3H), 7.23-7.26 (m, 3H), 7.52 (s, 1H), 7.55 (d, J= 8.0 Hz, 1H), 8.77 (d, J= 7.6 Hz, 1H), 12.72 (s, 1H).

[M+H] ⁺ 368. Example 24: (S)-3-(lH-indol-2-yl)-2-(5-methoxybenzofuran-2-carboxamido)p ropanoic acid

Prepared as in Example 22 from (S)-2-amino-3-(lH-indol-3-yl)propanoic acid and 5- methoxybenzofuran-2-carbonyl chloride (Example 13b) to give (S)-3-(lH-indol-2-yl)-2-(5- methoxybenzofuran-2-carboxamido)propanoic acid. 1H NMR (DMSO, 400 MHz): δ 3.20- 3.36 (m, 2H), 3.78 (s, 3H), 4.62-4.72 (m, 1H), 6.94 (td, J= 8.0, 1.2 Hz, 1H), 7.00-7.06 (m, 2H), 7.16 (d, J= 2.4 Hz, 1H), 7.23 ( d, J= 2.4 Hz, 1H), 7.29 (d, J = 7.6 Hz, 1H), 7.47 (d, J = 0.4 Hz, 1H), 7.52 (d, J = 9.2 Hz, 1H), 7.56 (d, J= 8.4 Hz, 1H), 8.70 (d, J= 8.0 Hz, 1H), 10.80 (s, 1H), 13.84 (s, 1H).

Example 25: (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(2- methoxyphenyl)propanoic acid

Prepared as in Example 22 from (S)-2-amino-3-(2-methoxyphenyl)propanoic acid and 5- methoxybenzofuran-2-carbonyl chloride (Example 13b) to give (S)-2-(5-methoxybenzofuran- 2-carboxamido)-3-(2-methoxyphenyl)propanoic acid. 1H NMR (DMSO, 400 MHz): 5 3.15 (dd, J = 13.6, 10.0 Hz, 1H), 3.24 (dd, J = 17.2, 7.6 Hz, 1H), 3.78 (s, 3H), 3.81 (s, 3H), 4.60- 4.70 (m, 1H), 6.80 (td, J = 7.2, 0.4 Hz, 1H), 6.94 (d, J = 8 Hz, 1H), 7.03 (dd, J = 8.8, 2.4 Hz, 1H), 7.14-7.20 (m, 2H), 7.23 (d, J = 2.0 Hz, 1H), 7.43 (d, J = 0.8 Hz, 1H), 7.54 (d, J = 8.8 Hz, 1H), 8.67 (d, J = 8.0 Hz, 1H), 10.80 (s, 1H), 12.78 (s, 1H).

Example 26 : (S)-3-(3-cyanophenyl)-2-(5-methoxybenzofuran-2-carboxamido)p ropanoic acid

Prepared as in Example 22 from (S)-2-amino-3-(3-cyanophenyl)propanoic acid and 5- methoxybenzofuran-2-carbonyl chloride (Example 13b) to give (S)-3-(3-cyanophenyl)-2-(5- methoxybenzofuran-2-carboxamido)propanoic acid. 1H NMR (DMSO, 400 MHz): δ 3.14 (dd, J = 13.6, 10.0 Hz, 1H), 3.24-3.29 (m, 1H), 3.78 (s, 3H), 4.64-4.70 (m, 1H), 7.03 (dd, J = 8.8, 2.8 Hz, 1H), 7.24 (d, J = 2.0 Hz, 1H), 7.43-7.47 (m, 2H), 7.54 (d, J = 9.2 Hz, 1H), 7.60- 7.64 (m, 2H), 7.74 (s, 1H), 8.87 (d, J = 7.6 Hz, 1H), 12.95 (s, 1H

Example 27: (S)-3-cyclohexy -2-(5-methoxybenzofuran-2-carboxamido)propanoic acid

Prepared as in Example 22 from (S)-2-amino-3-cyclohexylpropanoic acid and 5- methoxybenzofuran-2-carbonyl chloride (Example 13b) to give (S)-3-cyclohexyl-2-(5- methoxybenzofuran-2-carboxamido)propanoic acid. 1H NMR (DMSO, 400 MHz): δ 0.75- 1.41 (m, 6H), 1.51-1.23 (m, 7H), 3.71 (s, 3H), 4.39-4.50 (m, 1H), 7.03 (dd, J= 8.8, 2.4 Hz, 1H), 7.25 (d, J= 2.4 Hz, 1H), 7.52 (d, J= 0.8 Hz, 1H), 7.55 (d, J= 8.8 Hz, 1H), 8.77 (d, J = 8.0 Hz, 1H), 12.67 (s, 1H). [M+H] ⁺ 346.

Compounds described in Table HI were prepared as in Example 22 from 5- methoxybenzofuran-2-carbonyl chloride and the corresponding amino acid:

Table HI:

Example 28 : (S)-2-(5-methoxybenzofur an-2-carboxamido)-3-(2-methylbenzyloxy) propanoic acid

To a solution of (S)-methyl 3-(2-methylbenzyloxy)-2-(tritylamino)propanoate (Example 28a) (41 mg, 0.18 mmol) in dichloromethane was added a solution of trifluoroacetic acid (100 uL, 20% in DCM). The reaction was stirred for 30 minutes at room temperature then extracted with water. The aqueous solution was basified with 0.1 M potassium carbonate and extracted with dichloromethane. The organic layer was dried over sodium sulfate, filtered and evaporated. To the resulting amine in dichloromethane (3 mL) was added triethylamine (30 uL, 0.216 mmol) followed by 5-methoxybenzofuran-2-carbonyl chloride (example 13b) (38 mg, 0.18 mmol). The reaction mixture was stirred at room temperature for 2h then washed with water and brine. The organic layer was dried over sodium sulfate, filtered and evaporated. The resulting ester was dissolved in ethanol (2 mL) and 2 N NaOH (180 uL, 0.36 mmol) was added. The reaction was stirred at room temperature for 4 hours then neutralized with 1 M HCl solution, extracted with dicholormethane, dried over sodium sulfate, filtered and evaporated. The crude product was purified by RP HPLC (eluent: 10% to 25% acetonitrile/water) to give (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(2- methylbenzyloxy) propanoic acid (18 mg, 26 %). 1H NMR (DMSO, 400 MHz): δ 2.23 (s, 3H), 3.79 (s, 3H), 3.76-3.90 (m, 2H), 4.50 (q, J = 8.0 Hz, 2H), 4.66-4.70 (m, 1H), 7.05 (dd, J = 8.8, 2.0 Hz, 1H), 7.09-7.20 (m, 3H), 7.23-7.27 (m, 2H), 7.546 (d, J = 1.2 Hz 1H), 8.57 (d, J = 8.4 Hz, 1H), 13.00 (s, 1H). LC/MS; [M-H] expected 382.4; found 382.4.

Example 28a: (S)-methyl 3-(2-methylbenzyloxy)-2-(tritylamino)propanoate

(S)-methyl 3-(2-methylbenzyloxy)-2-(tritylamino)propanoate benzyltriethyl ammonium chloride (198 mg, 0.872 mmol), l-(Bromomethyl)-2-methylbenzene (128 uL, 0.959 mmol) and 40 % NaOH in water (113 uL, 1.13 mmol) were added sequentially to a solution of N- Trityl-L-serine methyl ester (315 mg, 0.872 mmol) in dichloromethane at 0° C. The resulting two phase mixture was allowed to warm to room temperature and stirred vigorously for 18h. The reaction mixture was washed with water, dried over sodium sulfate, filtered and evaporated. The residue was chromatographed on silica gel (hexane/ethyl acetate 85: 15 to 80:20) to give (S)-methyl 3-(2-methylbenzyloxy)-2-(tritylamino)propanoate as a colorless oil (332 mg, 82 %). MS466 [M+H].

Example 29: (S)-3-(2-hydroxybenzyloxy)-2-(5-methoxybenzofuran-2- carboxamido)propanoic acid

To a solution of (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(2-

(methoxymethoxy)benzyloxy)propanoic acid (Example 29a) (21.2 mg, 0.050 mmol) in THF (2 mL) at room temperature was added concentrated HCl (50 uL) and the reaction was stirred at room temperature overnight then poured into water and extracted with dichloromethane. The organic layer was dried over sodium sulfate filtered and evaporated. Purification on RP HPLC (eluent: 10% to 25% acetonitrile/water) gave (S)-3-(2-hydroxybenzyloxy)-2-(5- methoxybenzofuran-2-carboxamido)propanoic acid (15 mg, 78 %) as a white solid. 1H NMR (DMSO, 400 MHz): δ 3.79 (s, 3H), 3.76-3.90 (m, 2H), 4.48 (s, 2H), 4.64-4.70 (m, 1H), 6.72(td, J = 7.6, 0.8 Hz, 1H), 6.78 (dd, J = 8.0, 1.2 Hz, 1H), 7.05 (dd, J = 8.8, 2.0 Hz, 2H), 7.20 (dd, J = 7.6, 1.6 Hz, 1H), 7.25 (d, J = 2.4 Hz 1H), 7.54 (d, J = 0.4 Hz, 1H), 7.57 (d, J = 9.2 Hz, 1H), 8.58 (d, J = 8.0 Hz, 1H), 9.45 (s, 1H), 12.94 (s, 1H). LC/MS; [M-H] expected 384.4; found 384.4.

Example 29a: (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(2-(methoxymetho xy) benzyloxy)propanoic acid

Prepared as in Example 28 from (S)-methyl 3-(2-(methoxymethoxy)benzyloxy)-2- (tritylamino)propanoate (Example 29b) and 5-methoxybenzofuran-2-carbonyl chloride (Example 13b). Yield: 40 %. MS: 430 [M+H]

Example 29b: (S)-methyl 3-(2-(methoxymethoxy)benzyloxy)-2- (tritylamino)propanoate

Prepared as in Example 28a from l-(bromomethyl)-2-(methoxymethoxy)benzene (Example 29c). Yield 30%. MS: 512 [M+H]

Example 29c: 1 -(bromomethyl)-2-(methoxymethoxy)benzene To (2-(methoxymethoxy)phenyl)methanol (Example 29d) (1.3 g, 7.7 mmol) in dichloromethane (10 mL) and triethylamine (1.4 mL, 10.0 mmol) at 0 °C was added methanesulfonyl chloride (774 uL, 10.0 mmol). The reaction was stirred for lh at 0 °C. The reaction was quenched with 0.1 M potassium carbonate, diluted with water, extracted with dichloromethane, filtered and evaporated. The residue was dissolved in DMF (10 mL) and potassium bromide was added (3.6 g, 30 mmol). The reaction was stirred overnight at room temperature then diluted with water and extracted with diethyl ether. The organics were dried over sodium sulfate, filtered and evaporated to give l-(bromomethyl)-2- (methoxymethoxy)benzene (1.4 g, 80%).

Example 29d: (2-(methoxymethoxy)phenyl)methanol

To a solution of 2-(methoxymethoxy)benzaldehyde (1.08 g, 6.51 mmol) in methanol at 0°C was added sodium borohydride (296 mg, 7.81 mmol). The reaction was allowed to warm to room temperature and stirred at room temperature for 30 min. The reaction was quenched with ice, diluted with water, and extracted with ethyl acetate. The organics were dried over sodium sulfate and evaporated. Chromatography on silica (1 :1 hexane:ethyl acetate) gave (2- (methoxymethoxy)phenyl)methanol (800 mg, 73 %). MS: 169 [M+H]

Example 29e: 2-(methoxymethoxy)benzaldehyde

To a solution of 2-hydroxybenzaldehyde (858 uL, 8.2 mmol) and diisopropylethylamine (2.8 mL, 16.4 mmol) in dichloromethane (10 mL) at 0 °C was added dropwise

chloro(methoxy)methane (747 uL, 9.8 mmol). The reaction was stirred for lh at 0°C, then warmed to room temperature and stirred overnight. The reaction was poured into water and extracted with dichloromethane. The organics were dried over sodium sulfate filtered and evaporated. The residue was purified on silica gel (eluent: DCM) to give 2- (methoxymethoxy)benzaldehyde (1.08 g, 79 %) as a clear oil.

Example 30: (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(pyridin-2- ylmethoxy)propanoic aci

Prepared as in Example 28 from (S)-methyl 3-(pyridin-2-ylmethoxy)-2- (tritylamino)propanoate (Example 30a) and 5-methoxybenzofuran-2-carbonyl chloride (example 13b). Yield: 42 %. 1H NMR (DMSO, 400 MHz): δ 3.79 (s, 3H), 3.92 (dd, J = 10.0, 4.0 Hz, 1H), 3.97 (d, J = 10.0, 6.8 Hz, 1H), 4.61 (s, 2H), 4.66-4.70 (m, 1H), 7.05 (dd, J = 8.8, 2.8 Hz, 1H), 7.25-7.30 (m, 2H), 7.40 (d, J = 8.0 Hz 1H), 7.55 (d, J = 1.2 Hz, 1H), 7.58 (d, J = 9.6 Hz, 1H), 7.75 (td, J = 7.6, 1.6 Hz, 1H), 8.49-8.53 (m, 1H), 8.80 (d, J = 7.6 Hz, 1H), 13.00 (s, 1H). MS: 369.4

Example 30a: (S)-methyl 3-(pyridin-2-ylmethoxy)-2-(tritylamino)propanoate

Prepared as in Example 28a from 2-(bromomethyl)pyridine hydrobromide . Yield: 30%. MS: 453 [M+H]

Prepared as in Example 28 from (S)-methyl 3-(biphenyl-3-ylmethoxy)-2- (tritylamino)propanoate (Example 31a) and 5-methoxybenzofuran-2-carbonyl chloride (Example 13b). Yield: 30 %. 1H NMR (DMSO, 400 MHz): δ 3.78 (s, 3H), 3.83 (dd, J = 9.6, 4 Hz, 1H), 3.89 (dd, J = 10.4, 6.8 Hz, 1H), 4.56 (d, J = 2.4 Hz, 2H), 4.66-4.70 (m, 1H), 7.05 (dd, J = 8.8, 2.8 Hz, 1H), 7.23 (dd, J = 12.8, 2.8 Hz, 1H), 7.30-7.70 (m, 11H), 8.62 (d, J = 7.6 Hz, 1H), 13.00 (s, 1H). MS: 444.5 [M-H].

Example 31a: (S)-methyl 3-(biphenyl-3-ylmethoxy)-2-(tritylamino)propanoate Prepared as in Example 28a from 4-(bromomethyl)biphenyl. Yield: 26%. MS: 528 [M+H].

Example 32 : (S)-2-(5-methoxybenzofuran-2-carboxamido)-3-(3-methoxybenzyl oxy) propanoic acid

Prepared as in Example 28 from (S)-methyl 3-(3-methoxybenzyloxy)-2- (tritylamino)propanoate (Example 32a) and 5-methoxybenzofuran-2-carbonyl chloride (Example 13b). Yield: 40 %. 1H NMR (DMSO, 400 MHz): 3.67 (s, 3H), 3.78 (s, 3H), 3.79 (dd, J = 10.0, 4.4 Hz, 1H), 3.85 (dd, J = 10.8, 7.2 Hz, 1H), 4.49 (d, J = 2.8 Hz, 2H), 4.66-4.73 (m, 1H), 6.78-6.87 (m, 2H), 7.05 (dd, J = 8.8, 2.8 Hz, 1H), 7.21 (t, J = 7.2 Hz, 1H), 7.25 (d, J = 2.4 Hz, 1H), 7.55 (s, 1H), 7.56 (d, J = 9.6 Hz, 1H), 8.62 (d, J = 8.0 Hz, 1H), 13.00 (s, 1H). MS: 368.4 [M-H]

Example 32a: (S)-methyl 3-(3-methoxybenzyloxy)-2-(tritylamino)propanoate Prepared as in Example 28a from l-(bromomethyl)-3-methoxybenzene Yield: 49 %. MS: 482 [M+H]

Prepared as in Example 28 from (S)-methyl 3-(3-cyanobenzyloxy)-2-

(tritylamino)propanoate (Example 33 a) and 5-methoxybenzofuran-2-carbonyl chloride (Example 13b). Yield: 30 %. 1H NMR (DMSO, 400 MHz): δ 3.79 (s, 3H), 3.82 (dd, J = 9.2, 3.6 Hz, 1H), 3.90 (dd, J = 10, 6.8 Hz, 1H), 4.58 (d, J = 7.6 Hz, 2H), 4.68-4.75 (m, 1H), 7.05 (dd, J = 9.2, 2.8 Hz, 1H), 7.25 (d, J = 2.8 Hz, 1H) 6H), 7.50-7.80 (m, 6H), 8.71 (d, J = 8.0 Hz, 1H), 13.00 (s, 1H). MS: 393.4 [M-H]

Example 33a: (S)-methyl 3-(3-cyanobenzyloxy)-2-(tritylamino)propanoate

Prepared as in Example 28a from 3-(bromomethyl)benzonitrile . Yield: 59 %. MS: 477 [M+H. Example 34: (S)-3-(4-isopropylbenzyloxy)-2-(5-methoxybenzofuran-2- carboxamido)propanoic acid

Prepared as in Example 28 from (S)-methyl 3-(4-isopropylbenzyloxy)-2- (tritylamino)propanoate (Example 34a) and 5-methoxybenzofuran-2-carbonyl chloride (Example 13b). Yield: 25 %. 1H NMR (DMSO, 400 MHz): δ 1.14 (d, J = 6.8 Hz, 6H), 2.82 (sept, J = 7.2 Hz, 1H), 3.75-3.81 (m, 1H), 3.79 (s, 3H), 3.85 (dd, J = 10, 6.8 Hz, 1H), 4.46 (d, J = 2.0 Hz, 2H), 4.66-4.70 (m, 1H), 7.03-7.09 (m, 1H), 7.14-7.28 (m, 5H), 7.54-7.61 (m, 2H), 8.60 (d, J = 8.0 Hz, 1H), 13.10 (s, 1H). LC/MS; [M-H] expected 410.4; found 410.4.

Example 34a: (S)-methyl 3-(4-isopropylbenzyloxy)-2-(tritylamino)propanoate Prepared as in Example 28a from l-(bromomethyl)-4-isopropylbenzene Yield: 20 %. MS: 494 [M+H].

Compounds described in Table I were prepared as in Example 28 from 5- methoxybenzofuran-2-carbonyl chloride (Example 13b) and the corresponding substituted (S)-methyl 3 -(benzyloxy)-2-(tritylamino)propanoates .

Table I

acid

acid

Example 35: Sodium (S)-3-(benzyloxy)-2-(5-phenylfuran-2-carboxamido)propanoate

(S)-ethyl 3-(benzyloxy)-2-(5-phenylfuran-2-carboxamido)propanoate (Example 35a) 12.00 g (30.5 mmol) was dissolved in ethanol (100 mL) and treated dropwise at 0°C with NaOH (2.5 equivalent as 2M aqueous solution). The solution was stirred at the same temperature until LC-MS indicates complete conversion. The reaction was then neutralized with HC1 (2M aqueous solution), diluted with water (400 mL) and extracted with diethyl ether. The organic extract was washed with water and brine and concentrated to give a light yellow sticky material. That material was dissolved in diethyl ether (20 mL) and while stirring, a 10% aq. Na ₂ C0 ₃ solution (150 mL), pre-cooled to 0°C, was added. Stirring continued at 0°C while slowly removing ethyl ether with a flow of nitrogen gas. During that time a white aqueous suspension is formed. After complete dispersion of the organic into the aqueous phase, a nice homogeneous white suspension was observed. The suspension was filtered and washed quickly with a small amount of ice water. The solid was collected in a 500 mL round bottom flask and diethyl ether (350 mL) was added. The mixture was stirred for 5h, filtered and the solid collected was evaporated from water under high vacuum to give sodium (S)-3- (benzyloxy)-2-(5-phenylfuran-2-carboxamido)propanoate as a white solid (9.50 g, 24.52 mmol, 80%). 1H NMR (DMSO, 400 MHz): δ 3.85 (m, 2H), 4.54 (pseudoq, J= 12.0 Hz, 2H), 4.68 (m, 1H), 7.13 (d, J = 3.6 Hz, 1H), 7.23-7.44 (m, 7H), 7.48 (m, 2H), 7.92 (m, 2H), 8.56 (d, J= 8.4 Hz, 1H),. [M+2H] ⁺ 366.

Example 35a: (S)-ethyl 3-(benzyloxy)-2-(5-phenylfuran-2-carboxamido)propanoate Sodium carbonate (19.00 g) in water (190 mL) was cooled down to 0°C and (S)-ethyl 2- amino-3-(benzyloxy)propanoate hydrochloride (Example 35b) (10.56 g, 40.65 mmol) was added in one portion. The mixture was stirred at 0°C until complete disappearance of solid material. At this time, an oily suspension of organic free base is observed. While stirring vigorously and maintaining the temperature at 0°C, a solution of 5-phenylfuran-2-carbonyl chloride (Example la) (7.00 g, 33.88 mmol) in dioxane (190 mL) was added continuously at the same temperature. The final 1/3 of the dioxane solution was added in nearly one portion. After addition was completed, vigorous stirring continued for lh at 0°C. The reaction was then acidified at 0°C with a 2M aq. HC1 solution and extracted with diethyl ether. The organic extract was washed (x3) with a 2M aq. HC1 solution and concentrated to give a light yellow sticky material. That material was purified over silica gel using Hexane/ethyl acetate (4: 1) as eluent to give (S)-ethyl 3-(benzyloxy)-2-(5-phenylfuran-2-carboxamido)propanoate as a light yellow oil (12.66, 32.18 mmol, 95%). 1H NMR (DMSO, 400 MHz): 51.19 (t, J = 7.2 Hz, 3H), 3.85 (m, 2H), 4.13 (m, 2H), 4.55 (pseudoq, J = 12.0 Hz, 2H), 4.76 (m, 1H), 7.13 (d, J = 3.6 Hz, 1H), 7.25-7.44 (m, 7H), 7.48 (m, 2H), 7.93 (m, 2H), 8.76 (d, J= 8.0 Hz, 1H). [MH] ⁺ 394.

Example 35b: (S)-ethyl 2-amino-3-(benzyloxy)propanoate hydrochloride

Ethanol (50 mL) was cooled down to -15°C and thionyl chloride (7 mL) was added dropewise. After the addition was completed, the mixture was stirred for 20 min at the same temperature and (S)-2-amino-3-(benzyloxy)propanoic acid (10.00 g) was added in one batch. The reaction mixture was slowly warmed up to room temperature and stirred for 48h. While stirring vigorously, diethyl ether was added slowly until a nice precipitate is form. At that time, -450 mL of diethyl ether was added. The precipitate was filtered, washed with diethyl ether and dried under vacuum to give (S)-ethyl 2-amino-3-(benzyloxy)propanoate hydrochloride as a white powder in quantitative yield. [M-C1] ⁺ 223.

Biological Tests

EXPERIMENT 1: Identification of Antagonists of hT2R61/hT2R67

To identify antagonists, cell lines stably expressing hT2R61 and hT2R67,

respectively, together with the promiscuous chimeric G16g44 protein were generated.

Human T2R61 and T2R67 stable cell lines were plated onto matrigel coated 384-well plates at a concentration of 20,000 cells per well. The cells were cultured overnight in DMEM medium supplemented with 10% fetal bovine serum. Before the assay, cells were loaded with Fluo-4 calcium dye (4.5 uM in DPBS) at room temperature for 1 hour. The assay was performed on FLIPR-3. For T2R61 cell line, aristolochic acid (20 nM) was used as the activator. For T2R67, andrographolide (1 uM) was used. Compounds of the present invention were added together with the activator molecule. For inhibition dose response curves, the compounds were tested in the concentration range of 40-0.16 uM. Compounds of the invention have shown IC ₅₀ <30μΜ for either human T2R61 or human T2R67.

EXPERIMENT 2: Sensory Evaluation of T2R61/67 antagonists

Experiment 2a - hT2R61/67 antagonists reduce bitter taste of whey proteins Taste tests were performed with hT2R61/67 antagonists using a 2-alternative forced choice method. Whey samples with the antagonists were given to the taste panelists together with the same sample without antagonists, the panelists were asked to identify the bitterer sample within the pair. As shown in Table 1 , the panelists consistently identified the whey samples without antagonists as being bitterer than the ones with antagonists, indicating that the representative antagonists, i.e., Compounds A and B, reduced the bitter taste of whey proteins (5%-7% Whey Protein). Compound A and Compound B are two of the Examples as described above. Table 1. Whey protein taste test results with T2R61/67 antagonists

Experiment 2b - hT2R61/67 antagonists reduce bitter taste of Green Tea

Taste tests were performed with hT2R61/67 antagonists using a 2-alternative forced choice method. Green Tea samples with the antagonists were given to the taste panelists together with the same sample without antagonists, the panelists were asked to identify the bitterer sample within the pair. As shown in Table 2, the panelists identified the Green Tea sample without antagonist as being bitterer than the one with antagonist, indicating that the representative antagonist, i.e., Compound A, reduced the bitter taste of Green Tea (0.6% Green Tea). Compound A is one of the Examples as described above.

Table 2. Green Tea taste test results with T2R61/67 antagonist

Experiment 2c - hT2R61/67 antagonists reduce bitter taste of Menthol

Taste tests were performed with hT2R61/67 antagonists using a 2-alternative forced choice method. Menthol samples with the antagonists were given to the taste panelists together with the same sample without antagonists, the panelists were asked to identify the bitterer sample within the pair. As shown in Table 3, the panelists identified the Menthol sample without antagonist as being bitterer than the one with antagonist, indicating that the representative antagonist, i.e., Compound B, reduced the bitter taste of Menthol (2.5mM Menthol). Compound B is one of the Examples as described above.

Table 3. Menthol taste test results with T2R61/67 antagonist

Experiment 2d - hT2R61/67 antagonists reduce bitter taste of Rebaudioside A

Taste tests were performed with hT2R61/67 antagonists using a 2-alternative forced choice method. Rebaudioside A samples with the antagonists were given to the taste panelists together with the same sample without antagonists, the panelists were asked to identify the bitterer sample within the pair. As shown in Table 4, the panelists consistently identified the Rebaudioside A sample without antagonist as being bitterer than the one with antagonist, indicating that the representative antagonist, i.e., Compound B, reduced the bitter taste of Rebaudioside A (1000 ppm). Compound B is one of the Examples as described above. Table 4. Rebaudioside A taste test results with T2R61/67 antagonist

Experiment 2e - hT2R61/67 antagonists reduce bitter taste of Ace

Taste tests were performed with hT2R61/67 antagonists using a 2-alternative forced choice method. Ace K samples with the antagonists were given to the taste panelists together with the same sample without antagonists, the panelists were asked to identify the bitterer sample within the pair. As shown in Table 5, the panelists consistently identified the Ace K samples without antagonists as being bitterer than the ones with antagonists, indicating that the representative antagonists, i.e., Compounds A and B, reduced the bitter taste of Ace K (1000 ppm). Compound A and Compound B are two of the Examples as described above.

Table 5. Ace K taste test results with T2R61/67 antagonists

All publications and patent applications herein are incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations should be understood therefrom as modifications will be obvious to those skilled in the art. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed inventions, or that any publication specifically or implicitly referenced is prior art.

Embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.