| 摘要 |
A compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein R1 is a group -CR6=CHR7 where R6 is hydrogen, C1-8 alkyl, C2-8 alkenyl, heteroaryl C1-8 alkyl, aryl C1-8 alkyl, aryl or heteroaryl; R7 is hydrogen, C1-8 alkoxycarbonyl, C2-8 alkenyloxycarbonyl, hydroxycarbonyl, hydroxymethyl or formyl; in which any aryl, heteroaryl or alkyl moiety is optionally substituted; R2 is C1-6 alkoxy or hydroxy; R3 is an amino group or a derivative thereof; R4 is hydrogen; R5 is hydrogen or hydroxy or R2 and R5 together represent a bond. |
