Abstract 2-acetamido-2-deoxyaldohexopyranose polyacetates are transformed by the action of phosphorus pentachloride into 2-tetrachloroethylideneamino derivatives, the trans-2- acetamido-l-acetate system reacting more rapidly than the cis. A 1-acetamido-pyranosyl polyacetate afforded the 1-tetrachloroethylideneamino derivative and 2-O-trichloroacetyl-β- D-glucopyranosyl chloride. The latter was also observed, amongst other products, from ...