1,2,4-TRIAZINES - SYNTHESIS OF SELECTED MEMBERS OF THE S-TRIAZOLO[3,4-F]-[1,2,4]TRIAZINE AND TETRAZOLO[1,5-F][1,2,4]TRIAZINE RING-SYSTEMS

A convenient synthesis of 3‐amino‐6‐hydrazino‐5(2H)[1,2,4]triazinone 4 has been developed and a study of the reactions of 4 with aliphatic acids, orthoesters and miscellaneous active carbonyl reagents has been undertaken. When 4 was refluxed in either neat acid or orthoester in dimethylformamide, a facile ring closure reaction with the N‐1 nitrogen of the 1,2,4‐triazine ring occurs affording a novel series of 3‐aIkyl(aryl)‐8(5H)‐s‐triazolo[3,4‐f] [1,2,4]triazinones (6–11). Ring closure with carbon disulfide and cyanogen bromide is also reported affording 6‐amino‐3(2H)thio‐8(5H)‐s‐triazolo[3,4‐f] [1,2,4]triazinone 12 and 3,6‐diamino‐8(5H)‐s‐triazolo‐[3,4‐f] [1,2,4]triazinone 14, respectively. In addition 4 has been converted into 3‐amino‐6‐azido‐5(2H)‐1,2,4‐triazinone 15 which was employed in a study of azide‐tetrazole equilibrium affording 6‐amino‐8(5H)tetrazolo[1,5‐f][1,2,4]triazinone 16. Rates for interconversion at various temperatures were measured and an activation energy for the process determined. Copyright © 1979 Journal of Heterocyclic Chemistry