Synthesis of 5-substitutd 1-Hydroxy-1,2,3-trizaoles through directed lithiation of 1-(benzyloxy)-1,2,3-triazole

摘要

1-(Benzyloxy)-1,2,3-triazole, prepared by selective benzylation of 1-hydroxy-1,2,3-triaxole or by oxidative cyclization of 2-hydroazonoglyoxal O-bnzyloxime, was metalated exclusively at the 5-position upon treatment with n-butyllithium. The anion formed reacted with a series of electrophiles. In this way carbon, halogen, sulfur, silicon, and tin substituents could be introducd at the 5-position. Subsequent removl of the benzyl group by palladium-ctalyzed hydrogenolysis or by treatment with hydrochloric acid afforded the corresponding 5-substituted 1-hydroxyl-1,2,3-triazoles.