[Lengthening of the peptide chain at the C-terminal end of a glycosylamino acid].

An O-glycodipeptide was synthesized by lengthening the peptide chain on the C-terminal side of a glycosylamino acid unit. N-(Benzyloxycarbonyl)-3-O-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-L-threonine o-nitrophenyl ester and pentachlorophenyl ester were condensed with glycine benzyl ester to give both the same glycodipeptide, [N-(benzyloxycarbonyl)-3-O-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-L-threonyl]glycine benzyl ester (9). The two anomers, N-(benzyloxycarbonyl)-3-O-(2,3,4,6-tetra-O-acetyl-alpha- and beta-D-glucopyranosyl)-L-threonine pentachlorophenyl ester were also prepared. 1H-N.m.r. studies ascertained the structure and anomeric configuration expected.