Preparation and photolysis of 1-cyano-glycopyranosyl azides
作者:Jean-Pierre Praly、Carméla Di Stèfano、Gérard Descotes、René Faure、László Somsák、István Eperjesi
DOI:10.1016/0040-4039(95)00520-m
日期:1995.5
Treatment of 1-bromo-glycopyranosyl cyanides 1 and 4 with sodiumazide in dimethyl sulfoxide gave 1-cyano-glycopyranosyl azides 2 and 5 in high yield, which on photolysis resulted in new oxazepine derivatives 3 and 6.
Acetylated 1-azido-glycopyranosyl cyanides (of the (1R)- 2, and 16, 5, 7, (1R)- 11, and 12 configurations) and 19 were prepared fromacetylated 1-halogeno-d-glycopyranosyl cyanides and formamide, resp., by sodium azide in dimethyl sulfoxide. Acetylated (1S)- 14 and (1R)- 15 1-chloro-d-galactopyranosyl cyanides were obtained fromcyanide by lithium chloride in dimethyl sulfoxide. 1,3-Dipolar cycloaddition
Photolysis of glycopyranosyl azides C-1 substituted by cyano-, amido-, or tetrazolyl-groups
作者:Jean-Pierre Praly、Carméla Di Stèfano、László Somsák
DOI:10.1016/s0957-4166(99)00543-1
日期:2000.2
Photolysis of acetylated 1-cyano-D-glycopyranosyl azides led to the corresponding acetylated 4,5,6,7-tetrahydro-1,3-oxazepines, being isolated in moderate to good yields (34-58%). These ring-expanded compounds were formed by rearrangements involving migration of the endocyclic carbon atom attached to the anomeric centre. This seems to be the preferred reaction pathway, whatever the anomeric configuration (alpha/beta) of the acetylated 1-cyano-D-glycopyranosyl azide used as the substrate. Rearrangement occurred without changing the stereochemistry of the migrating carbon. Photo-rearrangement of D-glycopyranosyi azides having either a carboxamido- or a tetrazolyl-anomeric group gave complex reaction mixtures. (C) 2000 Elsevier Science Ltd. All rights reserved.