3-Methoxy-4-(2-nitrovinyl)phenyl glycosides as potential chromogenic substrates for the assay of glycosidases.

Selective glycosidation of 2,4-dihydroxybenzaldehyde with either 2,3,4, 6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide, 2-acetamido-3,4,6-tri-O-acetyl-alpha-D-glucopyranosyl chloride, or 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide afforded the corresponding 4-O-glycosyl derivatives. Subsequent O-methylation, O-deacetylation, and condensation with nitromethane afforded the appropriate beta-glycoside of 3-methoxy-4-(2-nitrovinyl)phenol. The phenol is highly coloured at alkaline pH so that these glycosides may be suitable as chromogenic substrates for the assay of glycosidases.