Patent ID: 8324265

Claim:
A compound represented by formula (I) or a pharmaceutically acceptable salt thereof, wherein R 1 optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted cycloalkyl, optionally substituted cycloalkenyl, optionally substituted aryl, optionally substituted heteroaryl or optionally substituted heterocycle, R 2 is a group of formula: —Y—R 5 , wherein Y is —O— or —S—, and R 5 is branched alkyl, R 3 is a group of formula: —C(═O)—Z—R 6 , wherein Z is —NR 7 — or —NR 7 —W—, and R 6 is optionally substituted cycloalkyl, optionally substituted cycloalkenyl, or optionally substituted heterocycle, R 7 is hydrogen or optionally substituted alkyl, and W is optionally substituted alkylene, R 4 is hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted cycloalkyl, optionally substituted cycloalkenyl, optionally substituted aryl, optionally substituted heteroaryl, or optionally substituted heterocycle, and X is ═N.