Syntheses of 2-acetamido-2-deoxy-4- O-α- D-glucopyranosyl-α- d-glucopyranose ( n-acetylmaltosamine) and 2-acetamido-2-deoxy-4- O-β- d-glucopyranosyl-α- d-glucopyranose

Abstract

Condensation of benzyl 2-acetamido-3,6-di- O-benzyl-2-deoxy-α- D-glucopyranoside with 2,3,4,6-tetra- O-benzyl-1- O-( N-methyl)acetimidoyl-β- D-glucopyranose gave benzyl 2-acetamido-3,6-di- O-benzyl-2-deoxy-4- O-(2,3,4,6-tetra- O-benzyl-α- D-glucopyranosyl)-α- D-glucopyranoside which was catalytically hydrogenolysed to crystalline 2-acetamido-2-deoxy-4- O-α- D-glucopyranosyl-α- D-glucopyranose ( N-acetylmaltosamine). In an alternative route, the aforementioned imidate was condensed with 2-acetamido-3- O-acetyl-1,6-anhydro-2-deoxy-β- D-glucopyranose, and the resulting disaccharide was catalytically hydrogenolysed, acetylated, and acetolysed to give 2-acetamido-1,3,6-tri- O-acetyl-2-deoxy-4- O-(2,3,4,6-tetra- O-acetyl-α- D-glucopyranosyl)-α- D-glucopyranose Deacetylation gave N-acetylmaltosamine. The synthesis of 2-acetamido-2-deoxy-4- O-β- D-glucopyranosyl-α- D-glucopyranose involved condensation of benzyl 2-acetamido-3,6-di- O-benzyl-2-deoxy-α- D-glucopyranoside with 2,3,4,6-tetra- O-acetyl-α- D-glucopyranosyl bromide in the presence of mercuric bromide, followed by deacetylation and catalytic hydrogenolysis of the condensation product.