beta-d-glucopyranosyl isocyanate in refluxing toluene. Deprotection of O-peracetylated N-beta-d-glucopyranosyl-N'-acyl ureas either under base (NaOMe in MeOH at or below rt) or under acid (KHSO(4) or AcCl in MeOH at rt) catalyzed transesterification conditions resulted in unavoidable partial cleavage of the N'-acyl moieties. Reaction of beta-d-glucopyranosylammonium carbamate with an isocyanate, isothiocyanate or isoselenocyanate