Cyclic meso-ionic compounds. Part 15. Synthesis, spectroscopic properties, and chemistry of 1,3,4-thiadiazolium-2-benzylidenehydrazinides and 1,2,4-triazolium-3-benzylidenehydrazinides

Abstract

The preparation of 1,3,4-thiadiazolium-2-benzylidenehydrazinides (8) and 1,2,4-triazolium-3-benzylidenehydrazinides (10), two novel types of meso-ionic heterocycle, is described. In aqueous ethanolic ammonia solution, rearrangement of the meso-ionic compound (8c) to the isomeric meso-ionic 1,2,4-triazolium-3-thiolate (18c) has been observed. The meso-ionic 1,3,4-thiadiazoles (8) yield the 1,3-dipolar cycloadducts (25) with 4-ptenyl-1,2,4-triazoline-3,5-dione (24).