Patent ID: 8859812

Claim:
A compound or pharmaceutically acceptable salt thereof selected from the formula (I): wherein X is selected from O, S and NR 5 ; R 1a and R 1b is optionally substituted aryl; R 2 is hydrogen, optionally substituted alkyl; R 3 is optionally substituted alkyl, optionally substituted aryl, optionally substituted cycloalkyl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted aralkyl, optionally substituted heteroaralkyl, or optionally substituted heterocyclylalkyl; R 4 is optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted heteroaralkyl, optionally substituted aralkyl or optionally substituted heterocyclylalkyl; R 5 is hydrogen, alkyl, aryl, or arylalkyl.