Synthesis of fused and nonfused heterocycles from 5-and 8-substituted 3-hydrazino-1,2,4-triazino [5,6-b] indole

The 7-and 10-substituted 1,2,4-triazolo[4',3':2,3][1,2,4]triazino[5,6-b]ind oles were prepared by the reaction of 5- and 8-substituted-3-hydrazino-1,2, 4-triazino[5,6-b]indole with formic acid or triethyl orthoformate. Reaction of the hydrazines with acetylacetone, ethyl acetoacetate and ethyl cyanoac etate gave the respective biheterocycles containing pyrazole and pyrazolone rings. Reaction of the hydrazines with carbondisulphide, thiourea, urea, e thyl chloroformate as well as nitrous acid have been investigated. Reaction of 5-allyl-3-methylthio-1,2,4-triazino[5,6-b]indole with ethanolamine foll owed by cyclization gave the imidazotriazinoindole.