Synthesis and characterisation of N-glycosyl amines from the reaction between 4,6-0-benzylidene-D-glucopyranose and substituted aromatic amines and also between 2-(o-aminophenyl)benzimidazole and pentoses or hexoses

Twelve N-glycosyl amines were synthesised using 4,6-O-benzylidene-D-glucopyranose and different substituted aromatic amines, including some diamines that resulted in bis-glycosyl amines. Another set of six N-glycosyl amines was synthesised using different hexoses and pentoses and 2-(o-aminophenyl)benzimidazole. All compounds were isolated as solid products and purified, their elemental compositions were established, and these were characterised by NMR (H-1 and C-13), UV-Vis, and FTIR spectroscopy, by FAB mass spectrometry (molecular-ion peaks gave molecular weights), and by their optical rotations. While the protected saccharide, 4,6-O-benzylidene-D-glucopyranose, exists as a mixture of P and a anomers in solution, the corresponding N-glycosyl amines were of only the P anomeric form as determined by NMR and FTIR spectroscopy. On the other hand, N-glycosyl amines synthesised from 2-(o-aminophenyl)benzimidazole prefer the a anomeric form, and in two cases a mixture of both the P and the alpha anomers were observed. The trends observed in the chemical shifts were compared among different products. (C) 2001 Elsevier Science Ltd. All rights reserved.