Synthesis of Two New Heterocyclic Systems: Furo[3′,2′:5,6]pyrimido[2,1-c][1,2,4]triazines and Furo[3,2-e][1,2,3,4]tetrazolo[1,5-a]pyrimidine

Two novel heterocyclic triazines and tetrazole systems were synthesized through cyclization of 2-hydrazino-furo[2,3-d]pyrimidine with alpha-haloketones and nitrous acid respectively in high yields. The starting 2-hydrazino-pyrimidine was synthesized from 4-imino-3,6-diphenyl-furo[2,3-d]pyrimidine-2(1H)-thione by methylation and subsequent nucleophilic displacement of methylthio group with hydrazine hydrate.