A compound of formula (I):
or a pharmaceutically acceptable salt or cleavable ester thereof, wherein RCONH- represents an organic acylamino group, and E is a carboxy group or a pharmaceutically acceptable salt or C,.,o alkyl or substituted C1-10 alkyl ester thereof or is a cyano group.
式 (I) 的化合物:或其药学上可接受的盐或可裂解酯,其中 RCONH- 代表有机酰
氨基,而 E 是羧基或其药学上可接受的盐或 C,.,o 烷基或取代的 C1-10 烷基酯或
氰基。