Patent ID: 8211933

Claim:
A compound of formula: or a pharmaceutically acceptable salt thereof, wherein: R 1 is hydrogen, or an optionally substituted group selected from C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 heteroalkyl, C2-C6 heteroalkenyl, C2-C6 heteroalkynyl, C3-C6 cycloalkyl, C3-C6 cycloalkenyl, C3-C6 heterocycloalkyl, C3-C6 heterocycloalkenyl, aryl, heteroaryl, alkoxy, thioalkyl, alkylsulfinyl, alkylsulfonyl, amino, thioamido, amidosulfonyl, alkoxycarbonyl, carboxamide, amino-carbonyl, and alkylamine-carbonyl; R 2 is an optionally substituted group selected from C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 heteroalkyl, C2-C6 heteroalkenyl, C2-C6 heteroalkynyl, C3-C6 cycloalkyl, C3-C6 cycloalkenyl, C3-C6 heterocycloalkyl, C3-C6 heterocycloalkenyl, aryl, heteroaryl, alkoxy, thioalkyl, alkylsulfinyl, alkylsulfonyl, amino, thioamido, amidosulfonyl, alkoxycarbonyl, carboxamide, amino-carbonyl, and alkylamine-carbonyl; R 3a is hydrogen; R 3b is hydrogen; R 4a and R 4b are each hydrogen; R 5a1 and R 5a2 are each hydrogen; R 5b1 and R 5b2 are each hydrogen; and R 6 is optionally substituted heterocycle selected from pyridinyl, pyrimidinyl, furanyl, thiophenyl, pyrrolyl, isoxazolyl, isothiazolyl, pyrazolyl, oxazolyl, thiazolyl, imidazolyl, 1,2,3-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, thiadiazolyl, 1,2,3-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, triazolyl, tetrazolyl, pyridazinyl, pyrazinyl, triazinyl, tetrazinyl, pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, azetidinyl, tetrahydropyranyl, tetrahydrofuranyl, and dioxanyl.