Patent ID: 7943653

Claim:
A compound having a structure according to formula (I): or a form thereof, wherein R 1a is hydrogen or alkyl; R 1b is selected from C 3-12 cycloalkyl, heterocyclyl, aryl, heteroaryl or alkyl, wherein alkyl is optionally substituted with carboxy, C 3-12 cycloalkyl, heterocyclyl, aryl or heteroaryl, wherein each instance of C 3-12 cycloalkyl, heterocyclyl, aryl or heteroaryl is optionally substituted with one, two, three or four substituents selected from alkyl, alkoxy, cyano, halogen, hydroxy, amino or alkylamino, and wherein heterocyclyl optionally has one nitrogen ring atom attached to the formula (I) nitrogen atom, wherein said nitrogen ring atom is optionally further substituted with alkyl to form a quaternary ammonium salt; alternatively, R 1a and R 1b are taken together with the nitrogen atom of attachment to form a ring selected from piperidinyl or piperazinyl; and, R 2 and R 3 are each selected from one or two alkyl, alkoxy, cyano or halogen substituents.