Patent ID: 7781460

Claim:
A compound having the structure of Formula Ia its pharmaceutically acceptable salts, enantiomers, or diastereomers wherein R 1 and R 2 are independently selected from hydrogen, alkyl, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heterocyclyl, cycloalkyl, alkoxy, halogen or —OH; R 3 is alkyl, alkenyl, alkynyl, cycloalkyl, carboxy, heteroaryl, heterocyclyl, aryl, heteroarylalkyl, heterocyclylalkyl, aralkyl or carboxyalkyl; and R 4 is cyano, cycloalkyl, aryl, heteroaryl, heterocyclyl, aralkyl, heteroarylalkyl, heterocyclylalkyl, —CONHNH 2 , —C(═NOH)NH 2 or carboxyalkyl.