| abstract |
Compounds of general formula (I) or salts thereof are useful as preventive o r therapeutic agents for diabetes and so on wherein R1 is an optionally substituted hydrocarbon group or the like; X is a free valency or the like; Y is oxygen or the like; A is a heterocycle or the like; R2 is hydrogen or the like; R3 is OR9 or the like; and R4 and R5 are each hydrogen or the like, wi th the provisos that when A is optionally substituted indole, Y is not oxygen o r sulfur, that when Y is oxygen, sulfur, -SO-, -SO2-, or -NR8-, A is not an optionally substituted benzene ring, and that when Y is oxygen and A is an optionally substituted, 4-pyrone, 4-pyridone, or pyridine N-oxide ring, R2 i s not a thiazolyl or thiadiazolyl group substituted with optionally protected amino. |