Patent ID: 7271173

Claim:
A compound of formula I: or a pharmaceutically acceptable salt thereof, wherein X includes the carbon atoms at positions 1 and 2 and is selected from Y is H, oxo, or methyl; R is selected from H, C 1-7 alkyl, C 2-7 alkenyl, C 2-7 alkynyl, C 2-6 heterocyclyl, C 6-12 aryl, C 7-14 alkaryl, C 3-10 alkheterocyclyl, and C 1-7 heteroalkyl; R 1 is H; R 4 is H and R 2 and R 3 combine to form a fused six-membered ring in which position 4 is connected to position 5 by Z is —NHR 5 ; and R 5 is H.