Functionalised 1,2,4-Triazino[5,6-b]indoles

Abstract

3-Ethoxycarbonylmethylthio-5 H-1,2,4-triazino[5,6- b]indole (2) and 5-ethoxycarbonylmethyl-3-ethoxycarbonyl-methylthio-5 H-1,2,4-triazino[5,6- b]indole (4) have been prepared from 2,5-dihydro-3 H-1,2,4-triazino[5,6- b]indole-3-thione (1). The reaction of 2 and 4 with hydrazine hydrate gave the respective mono- and bishydrazide derivatives 3 and 5. Reaction of the monohydrazide 3 with acetylacetone, various carbonyl compounds and monosaccharides afforded the respective hydrazones 6 and 8–14. Dehydrative cyclization of 6 and 9 with boiling acetic anhydride afforded the pyrazole and 1,3,4-oxadiazoline derivatives 7 and 15, and reaction of 3 with CS2/KOH followed by hydrazinolysis afforded 16.