摘要:
EDC mediated coupling of the 4-O-succinoyl glycosyl azide 2 with glycosylamine 3 gave the protected glycosylazide 4. Hydrogenation of 4 afforded the glycosylamine 5. Chemoselective hydrolysis of the reducing end glycosylamine, followed by hydrogenation afforded N,N"-diacetylpseudochitotriose 7. Coupling of 5 with heterocyclic or with Cbz protected aliphatic amino acids yielded glycosyl amides 8-12. Deprotection of 11 and 12 afforded the N,N'-diacetylpseudochitotriosyl amides of beta-alanine, 13, and L-arginine, 14. Molecular modelling calculations revealed that the pseudotrisaccharides exist in low energy extended conformations which show similar space filling as N,N',N"-triacetylchitotriose.