Methods for their preparation and Shiasutachin B derivative with a glycosidase inhibitory activity

摘要

A compound of the formula (I): CHEM and a compound of the formula (V): CHEM as well as a compound of the formula (X): CHEM which are each a novel siastatin B derivative having a potent inhibitory activity against a glycosidase, are now synthesized by new processes. The compound of the formula (I), the compound of the formula (V) and the compound of the formula (X) have a potent enzyme-inhibitory activity to a glycosidase, which is particularly N-acetyl-galactosaminidase, galactosidase, glucosidase and mannosidase.