Catalyst-free assembly of a polyfunctionalized 1,2,4-triazole-fused N-heterocycle, 6-acylated pyrrolo[1,2-a][1,2,4]triazolo[5,1-c]pyrazine

A catalyst-free synthetic route to a new 1,2,4-triazole-pyrrolo[1,2-a]pyrazine hybrid system, 6-acylpyrrolo[1,2-a][1,2,4]triazolo[5,1-c]pyrazine, was realized upon sequential exposure of pyrrole-2-carbonitrile-derived substrates to DMF-DMA and acyl hydrazide through which acylated pyrazine and 1,2,4-triazole rings were consecutively formed with the formation of multiple bonds (one C-C bond and three C-N bonds). This annulative functionalization approach towards N-fused polycycles enabled us to install various substituents at specific positions on the core skeleton.