Synthesis of new pentaheterocyclic systems based on the triazolo[3,4-a]-2,7-naphthyridine core

Abstract

An efficient synthesis of new pentaheterocyclic systems based on the triazolo[3,4-a]-2,7-naphthyridine core is described. Thus, by cyclocondensation of thieno [2,3-c][1,2,4]triazolo[3,4-a]-2,7-naphthyridine with formamide, the corresponding thieno[3,2-d]pyrimidine was obtained, starting from which the N-alkyl, 11chloro and 11-amino(hydrazino) derivatives were synthesized. Furthermore, reaction of pyrazolo [3,4c][1,2,4]triazolo(tetrazolo)-2,7-naphthyridines, formed via a condensation/cyclization process, with acetylacetone gave new pentaheterocyclic pyrazolo [3,4-c][1,2,4]triazolo(tetrazolo)-2,7-naphthyridine system.