Abstract
N-Benzyloxycarbonyl-DL-aspartic acid α-benzyl ester was prepared from N-benzyl-oxycarbonyl-L-aspartic anhydride on racemisation in the prersence of dicyclohexylamine and condensed with 2-acetamido-2-deoxy-3, 4, 6-tri-O-acetyl-β-D-glucosylamine to give diastereomeric two glycopeptide acetates, 1-(α-benzyl N-benzyloxycarbonyl-L-β-aspart-amido)-2-acetamido-1, 2-dideoxy-3, 4, 6-tri-O-acetyl-β-D-glucose and 1-(α-benzyl N-benzyloxycarbonyl-D-β-aspartamido)-2-acetamido-1, 2-dideoxy-3, 4, 6-tri-O-acetyl-β-D-glucose. Both compounds were subjected to hydrogenolysis and de-O-acetylation to give the resulting two glycopeptide, N-(L-β-aspartyl)-2-acetamido-2-deoxy-β-D-glucosylamine and N-(D-β-aspartyl)-2-acetamido-2-deoxy-β-D-glucosylamine.
