An Improved Synthesis of 2‐Acetamido‐2‐deoxy‐ D‐gluconohydroximolactone (PUGNAc), A Strong Inhibitor of β‐N‐Acetylglucosaminidases

O‐(2‐Acetamido‐3,4,6‐tri‐O‐acetyl‐D ‐glucopyranosylidene)amino N‐phenylcarbamate ( 1 ), an established inhibitor of β‐N‐acetylglucosaminidases, has been prepared by an improved six‐step synthesis from N‐acetyl‐D ‐glucosamine.