The photohydration of N-glycosylpyridinium salts and of related pyridiniumN,O-acetals

The photolysis of N-MEM-pyridinium chloride (1e) in alkaline H2O gave N-MEM -6-azabicyclo[3.1.0]hexenol (2e). With benzoic acid in CHCl3, this bridged aziridine gave a complex aminal 7 reminiscent by its C-2 symmetry of Troger 's base. Photolysis of alpha-D-glucopyranosyl pyridinium chloride (alpha-12 ) gave a 1:1 mixture of the corresponding alpha-D-glucopyranosyl aziridines (alpha-13/alpha-14), which were separated, after peracetylation, by crysta llisation. The absolute configuration of one of the bridged aziridines (alp ha-16) was established by X-ray analysis. (C) 2000 Elsevier Science Ltd. Al l rights reserved.