Stereospecificity of the O→N acyl migration in 2,3,4,6-tetra- O-benzoyl-β- D-mannopyranosylamine

Abstract

By heating tetra- O-benzoyl-α- D-mannopyranosyl bromide with sodium azide, 2,3,4,6-tetra- O-benzoyl-β- d-mannopyranosyl azide ( 3) was obtained. Catalytic hydrogenation of 3 produced 2,3,4,6-tetra- O-benzoyl-β- d-mannopyranosylamine ( 4). Ammonolysis of 4 afforded N-benzoyl-β- d-mannopyranosylamine ( 7) in good yield (60%) and a mixture of d-mannose and d-mannopyranosylamine (34%). No other compound was characterized. This result shows that, in O-acylated glycosylamines, O→N acyl migration is stereospecific and takes place when there is a cis relation between the O-acyl group at O-2 and the amino group at C-1.