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

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 (1H and 13C), 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 β and α anomers in solution, the corresponding N-glycosyl amines were of only the β anomeric form as determined by NMR and FTIR spectroscopy. On the other hand, N-glycosyl amines synthesised from 2-(o-aminophenyl)benzimidazole prefer the α anomeric form, and in two cases a mixture of both the β and the α anomers were observed. The trends observed in the chemical shifts were compared among different products.