SYNTHESIS OF 5-SUBSTITUTED 1-HYDROXY-1,2,3-TRIAZOLES THROUGH DIRECTEDLITHIATION OF 1-(BENZYLOXY)-1,2,3-TRIAZOLE

1-(Benzyloxy)-1,2,3-triazole, prepared by selective benzylation of 1-h ydroxy-1,2,3-triazole or by oxidative cyclization of 2-hydrazonoglyoxa l O-benzyloxime, was metalated exclusively at the 5-position upon trea tment with n-butyllithium. The anion formed reacted with a series of e lectrophiles. In this way carbon, halogen, sulfur, silicon, and tin su bstituents could be introduced at the 5-position. Subsequent removal o f the benzyl group by palladium-catalyzed hydrogenolysis or by treatme nt with hydrochloric acid afforded the corresponding 5-substituted 1-h ydroxy-1,2,3-triazoles.