Synthesis of nu-triazole derivatives from anomeric sugar diazides

Staudinger reaction of acetylated glycopyranosylidene 1,1-diazides led to r esonance-stabilized iminophosphoranes (phosphinimines) of 6,7-dihydro[3,4-d ]-1,2,3-triazole. This unprecedented transformation involves p-elimination of acetic acid and cycloaddition of azide anion to the resulting C-2 double bond. Transformation of the new fused heterocyclic iminophosphoranes on tr eatment with aqueous ethanolic ammonia gives carboxamidine derivatives of v -triazole bearing a chiral trihydroxypropyl side-chain. Crystal structure o f 5-(D-erythro-1',2',3'-trihydroxypropyl)-1,2,3-triazole-4-carboxamidine wa s established by X-ray crystallography. (C) 1999 Elsevier Science Ltd. All rights reserved.