The Synthesis of Antigenic Glycopeptides, 2-Acetamido-N-(β-l-aspartyl)-2-deoxy-4-O-β-(d-galactopyranosyl)-β-d-glucopyranosylamine. (N-Acetyllactosaminyl-l-asparagine)

Abstract

Abstract The title compound, serving as intermediate in the chemical and biochemical synthesis of glycopeptides and as a reference substance in the structure elucidation of glycoproteins, was synthesized. 2-Acetamido-4-O-allyl-3,6-di-O-benzyl-2-deoxy-β-d-glucopyranosyl azide was reduced to the corresponding β-d-glucosylamine and coupled with 1-benzyl N-benzyloxycarbonyl-l-aspartate to give 2-acetamido-4-O-allyl-3,6-di-O-benzyl-N-[(S)-3-benzyloxycarbonyl-3-benzyloxycarbonylamino)propionyl]-2-deoxy-β-d-glucopyranosylamine. Removal of the allyl group of the latter followed by condensation with 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide gave the fully protected N-acetyllactosaminyl-l-asparagine. De-blocking of the O-acetyl, benzyl, and benzyloxycarbonyl groups gave the title compound.