Synthesis and Glycosidase Inhibitory Activity of 5a-Carba-α-DL-fucopyranosylamine and -galactopyranosylamine

5a-Carba-α-DL-fucopyranosylamine (DL-5) and -galactopyranosylamine (DL-4) have been synthesized in a conventional manner from 2,3,4,6-tetra-O-acetyl-5a-carba-β-DL-glucopyranosyl bromide (6). Only compound DL-5 has been shown to be a strong inhibitor (Ki = 2.3 × 10−7M) of α-fucosidase (bovine kidney). They did not exhibit any inhibitory activity towards five glycoside hydrolases, namely α- and β-glucosidases and α- and β-galactosidases.