Synthesis and Properties of 6-Amino-7-hetaryl-5-R-5H-pyrrolo[2,3-b]pyrazine-2,3-dicarbonitriles

We have established that when 5-chloro-6-cyano(2,3-dihydro-1-R-benzod]azol-2-yl)methyl]-2,3-pyrazinedicarbonitriles are reacted with nucleophilic reagents (aliphatic and aromatic amines, hydrogen sulfide), annelation of the five-membered ring occurs on the b] face of the pyrazine with formation of 6-amino-7-hetaryl-5-R-5H-pyrrolo2,3-b]pyrazine-2,3-dicarbonitriles and 6-amino-7-(1H-benzod]imidazol-2-yl)thieno2,3-b]pyrazine-2,3-dicarbonitrile respectively. Further heating with excess of acylating reagent leads to formation of a novel heterocyclic system 1H-benzo4,5]imidazo1,2-c]pyrazino2',3':4,5]pyrrolo3,2-e]pyrimidine. Reaction of vicinal dinitriles with hydrazine hydrate leads to the novel system 1H-pyrrolo2',3':5,6]pyrazino2,3-d]pyridazine.