摘要:
We have explored the rich structural diversity provided by an a-azido ester derived from D-arabinose as the source of sugar templates with reduced conformational flexibility. Using transient alpha-thioureido(selenoureido) esters we have prepared spiranic thio(seleno)hydantoins at the C-3 position of the sugar moiety. In this context, the first example of a stable spiranic alpha-lactam (or aziridinone) was isolated as a by-product in the hydrogenolysis of the starting alpha-azido ester. Furthermore, using copper(I)-catalyzed azido-alkyne cycloaddition (click chemistry), we have accessed bicyclic cis-fused alpha-triazolyl lactones fixed in the furanose form. Spiranic thiohydantoins turned out to be moderate, though selective, inhibitors of glycosidases, whereas their selenium isosters behaved as good free radical scavengers. (C) 2012 Elsevier Ltd. All rights reserved.