Am. Amer, SYNTHESIS OF 1,2,4-TRIAZOLIUM SALTS - REACTION OF 1-AZO-2-AZONIA-ALLENE SALTS WITH NITRILES, Monatshefte fuer Chemie, 126(4), 1995, pp. 431-437
Alkyl ketone hydrazones 1 are oxidized with tert-butylhypochlorite to
give geminal chloro azo compounds 2. These react with SbCl5, to give 1
-aza-2-azonia-allene salts 3 as reactive intermediates which are inter
cepted with nitriles to yield 3H-1,2,4-triazolium salts 5. In most cas
es these salts rearrange spontaneously to form 1H-triazolium salts 6.
Hydrolysis of 6e-g by NaOH provide bases 7a-c, which react with picric
acid to give 1H-pyrazolium picrates 8.