Reaktion von 2,3,4-tri- O-acetyl-1,6-anhydro-β- D-glucopyranose mit as.-Dihalogenmethyläther

Abstract

2,3,4-Tri- O-acetyl-1,6-anhydro-β- D-glucopyranose ( 1) reacts with excess of dichloromethyl methyl ether to give 2,3,4-tri- O-acetyl-6- O-(dichloromethyl)-α- D-glucopyranosyl chloride ( 4); with 1.2–1.3 moles/mole of the ether, compound 1 gives 2,3,4-tri- O-acetyl-6- O-formyl-α- D-glucopyranosyl chloride ( 3). Compound 4 was very readily hydrolysed by thin-layer chromatography on silica gel to give compound 3 and 2,3,4-tri- O-acetyl-α- D-glucopyranosyl chloride ( 6). With silver acetate-acetic acid, compounds 3 and 4 give 1,2,3,4-tetra- O-acetyl-6- O-formyl-β- D-glucopyranose ( 8) which may also be obtained by formylation of 1,2,3,4-tetra- O-acetyl-β- D-glucopyranose with the N, N-dimethylformamide-phosgene reagent. With 1.2 moles/mole of dibromomethyl methyl ether, compound 1 is converted into 2,3,4-tri- O-acetyl-6- O-formyl-η- D-glucopyranosyl bromide ( 10). Treatment of compounds 3 and 10 with ethanol-silver carbonate gives the ethyl β- D-glucoside derivative.