Regioselective Access to 1,2,4-Triazole-Fused N -Heterocycle, Pyrrolo[1,2- a ][1,2,4]triazolo[5,1- c ]pyrazine, via Double Dehydrative Cyclizations.

A highly efficient and regioselective approach to a novel 1,2,4-triazole-fused N -heterocyclic scaffold, pyrrolo[1,2- a ][1,2,4]triazolo[3,4- c ]pyrazine, was established by base-promoted reaction of pyrrole-2-carbonitrile-derived substrate with acyl hydrazide where domino double ring closures comprised of enamine formation, attack on nitrile, and cyclodehydration enabled sequential construction of pyrazine and 1,2,4-triazole ring systems with formation of three C-N bonds.