Patent ID: 8394807

Claim:
A compound of the formula or a pharmaceutically acceptable salt, thereof; wherein R a is 6-aryloxy; R 1 is hydrogen; R 2 is cycloalkyl or heterocyclyl, each of which is optionally substituted; R 3 is selected from the group consisting of alkyl, alkenyl, heteroalkyl, cycloalkyl, cycloalkenyl, heterocyclyl, aryl, arylalkyl, heteroaryl, and heteroarylalkyl, each of which is optionally substituted; or R 3 and the attached nitrogen form an amino acid or an ester or amide derivative thereof; X 1 is C 1 -C 4 alkylene; and Y 1 is N(R 4 ) or OC(O)N(R 4 ); R 4 is hydrogen, or R 4 is X 2 —Z, where X 2 is a bond or a C 1 -C 4 alkylene group; and Z is alkyl, alkenyl, heteroalkyl, cycloalkyl, cycloalkenyl, heterocyclyl aryl, or heteroaryl, each of which is optionally substituted.