Patent ID: 7745657

Claim:
A compound of Formula I or a pharmaceutically acceptable salt thereof, wherein R 1 and R 2 are independently selected from the group consisting of: R a , —C(O)—R a , and —C(O)—N(R a )R a ; R 3 and R 4 are independently selected from the group consisting of: hydrogen, C 1-10 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-10 cycloalkyl, aryl, heteroaryl, heterocyclyl, and C 1-10 fluoroalkyl; and each Ra is independently selected from the group consisting of: hydrogen, C 1-10 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-6 cycloalkyl, aryl, heteroaryl, heterocyclyl, and C 1-10 fluoroalkyl.