Recherches en série triazépine-1,2,4 XIII. Hydrazinolyses de thioxo-3 oxo(thioxo)-5 triazépines-1,2,4

The ring interconversion of 2,7-dimethyl-3-thioxo-5-oxo(thioxo)-1,2,4-triazepines into pyrazolones, 3-hydrazinopyrazoles or tetrazocyne by hydrazinolysis are described. The hydrazine and methylhydrazine reactions afforded 2-methyl thiosemicarbazide and 3(5)-pyrazolones by breaking of the two N(1)-C(7) and N(4)-C(5) bonds in the triazepinone ring. The reaction with phenylhydrazine is different. In this case three reaction centres must be taken into account: 3, 5 and 7 positions. Hydrazinolysis of 5-thioxo-1,2,4-triazepine is more complicated and depends on the experimental conditions. The mechanism suggested is addition of two molecules of hydrazines in the 5 position followed by a transannular reaction to the 7 position for hydrazine and to the 3 and 7 position for phenylhydrazine.