Patent ID: 8193357

Claim:
A compound of Formula I: wherein: R 1 and R 3 each independently is selected from among hydrogen, optionally substituted C 1 -C 4 alkyl, C 1 -C 4 heteroalkyl, C 1 -C 4 haloalkyl, optionally substituted heteroaryl, and optionally substituted aryl; or R 1 and R 3 taken together form a C 3 -C 8 carbocyclic ring; R 2 and R 4 are each hydrogen; or R 2 and R 4 taken together form a bond; R 5 is selected from among hydrogen, C 1 -C 8 alkyl, C 1 -C 8 haloalkyl, C 1 -C 8 heteroalkyl, C 7 -C 10 arylalkyl, and C 2 -C 8 heteroarylalkyl; and R 6 is hydrogen or F; and pharmaceutically acceptable salts thereof.