Triazolium perchlorate

The intramolecular iodine-promoted cyclization of 2-(2-methyl-2-propenylthio)-l,2,4-triazoles 317 exclusively afford the corresponding thiazolo[3,2-3][l,2,4]triazolium perchlorates 318 (Equation 55) <1999RJOC730>. 

Fig.2 The chiral triazolium perchlorate salt 2 synthesized in Enders group...

On the other hand, generation of free carbenes can be thermally achieved from C-protected NHC . In 1995, Enders reported the thermal elimination of methanol from 5-methoxy-l,3,4-triphenyl-4,5-dihydro-l//-l,2,4-triazole (12) affording the corresponding carbene l,2,4-triazol-5-ylidene (13) in quantitative yield (Scheme 2). Methanol adduct (12) is easily synthesized from reaction of triazolium perchlorate (11) and NaOCH3 in methanol. 

Triazolium salts. 2,3,5-Triphenyl-l,3,4-oxadiazolium perdilorate heated briefly with aniline in acetic acid -> l,3,4,5-tetraphenyl-l,2,4-triazolium perchlorate. Y ca. 100%. F. e., also triazoles with NH -acetate, s. G. V. Boyd and A. J. H. Summers, Chem. Commun. 1968, 549. 

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