Heterocyclic compounds and methods of their use

A compound of formula (I):

• wherein:
• X is absent and Y is —CHR3CHR4CH2—, —CH2CHR3CHR4, —CH2CH2CHR3—, —CR3═CHCH2—, —CH═CHR3CH2— or —CH2CH═CR3—;
• or
• X is —CHR5 and Y is —CHR3CHR4—, —CHR3CR4═, —CH2CHR3—, —CR3═CH— or —CH═CR3—, wherein when Y is —CHR3CR4═, R2b is absent, or
• X is —CH2CHR5— or C(═O)CHR5— and Y is —CHR3—;
• R1 is —C(═O)CH(aryl)(aryl), —C(═O)CH(aryl)(cycloalkyl), —C(═O)CH(cycloalkyl)(cycloalkyl), —C(═O)N(aryl)(aryl), —C(═O)N(aryl)(cycloalkyl) or —C(═O)N(cycloalkyl)(cycloalkyl);
• R2 is —C1-4alkylenearyl, —OC1-3alkylenearyl, —OC2-3alkenylenearyl, —OC2-3alkynylenearyl, —OC1-3alkylenecycloalkylaryl, -OarylOaryl, —SC1-3alkylenearyl, —SO2C1-3alkylenearyl, —NHC1-8alkyl, —NHC1-3alkylenearyl, —NHC1-3alkyleneheteroaryl, —NHC2-3alkynylenearyl, —N(CH3)C1-8alkyl, —N(CH3)C1-3alkylenearyl, —N(CH3)C1-3alkyleneheteroaryl, —N(CH3)C2-3alkynylenearyl, —CH2OC1-3alkylenearyl, —N(CH3)C1-3alkylenecycloalkyl or —NHC1-3alkylenecycloalkyl;
• R2b is hydrogen;
• R3 is CO2H, —CH2CO2H, —C(═O)C(═O)OH, —C(═O)NHSO2C1-6alkyl, —C(═O)NHSO2phenyl, —C(═O)NHSO2CF3, —SO3H or —PO3H2;
• R4 is hydrogen or R3 and R4 together form a group:
• R5 is hydrogen;
• and
• wherein each cycloalkyl, cycloalkenyl, aryl, heterocyclyl and heteroaryl may be optionally substituted with one or more optional substituents selected from the group consisting of C1-6alkyl, C2-6alkenyl, C3-6cycloalkyl, oxo(═O), —OH, —SH, C1-6alkylO—, C2-6alkenylO—, C3-6cycloalkylO—, C1-6alkylS—, C2-6alkenylS—,
• C3-6cycloalkylS—, —CO2H, —CO2C1-6alkyl, —NH2, —NH(C1-6alkyl), —N(C1-6alkyl)2, —NH(phenyl), —N(phenyl)2, —CN, —NO2, -halogen, —CF3, —OCF3, —SCF3, —CHF2, —OCHF2, —SCHF2, -phenyl, -heterocyclyl, -heteroaryl, -Oheteroaryl, -Oheterocyclyl, -Ophenyl, —C(O)phenyl, —C(O)C1-6alkyl;
• wherein heterocyclyl is selected from the group consisting of azetidine, tetrahydrofuranyl, tetrahydrothiophenyl, pyrrolidinyl, 2-oxopyrrolidinyl, pyrrolinyl, pyranyl, dioxolanyl, piperidinyl, 2-oxopiperidinyl, pyrazolinyl, imidazolinyl, thiazolinyl, dithiolyl, oxathiolyl, dioxanyl, dioxinyl, dioxazolyl, oxathiozolyl, oxazolonyl, piperazinyl, morpholino, thiomorpholinyl, 3-oxomorpholinyl, dithianyl, trithianyl and oxazinyl;
• or a pharmaceutically acceptable salt thereof.