Synthesis and Reactions of 8-Hydrazinofuro[2',3':4,5]pyrrolo-[1,2-d][1,2,4]triazines

Abstract

5-Ethyl-8-hydrazinofuro[2',3':4,5]pyrrolo[1,2-d][1,2,4]triazine (4a) and its 2-methyl derivative 4b were prepared from 4H-furo[3,2-b]pyrrole-5-carbohydrazides 1a and 1b, respectively. Compounds 1a and 1b reacted with triethyl orthopropionate to give 2a and 2b which afforded with phosphorus(V) sulfide corresponding thiones 3a and 3b. The title compounds 4a and 4b were made by treatment of 3a and 3b with hydrazine hydrate. By reactions of triethyl orthoesters with the title compounds and similar derivatives furo[2'3':4,5]pyrrolo[1,2-d][1,2,4]triazolo[3,4-f][1,2,4]triazines 5a-5j were prepared. Reactions of compounds 4 with some aldehydes and isocyanates led to hydrazones 6a-6c and semicarbazones 7a and 7b, respectively.