Syntheses of heterocyclic compounds. Part XXXI. Triazolium tetrafluoroborates from the cycloaddition of alkoxydiazenium salts to azines, hydrazones, and anils derived from aromatic aldehydes

Abstract

The azomethine group in aromatic aldehyde azines and in o-dialkylamino-substituted aromatic Schiff's bases undergoes cycloaddition with alkoxydiazenium salts in dry dichloromethane to yield triazolium salts. Aromatic aldehyde hydrazones gave the triazolium salts (15) by a regiospecific cycloaddition, confirmed by an independent synthesis. Some reactions and physical data of these heterocycles and mechanistic aspects of their formation are discussed.