Synthesis of pyrido[3,2-e]pyrrolo[2,1-c][1,2,4]triazines from pyrido[3,2-e][1,2,4]triazine derivatives

In carrying on our interest in heteropolycyclic structures with biological activities, we projected the preparation of compounds containing the pyrido3,2-e]1,2,4]triazine or pyrido2,3-b]1,4]triazepine systems. The established synthetic approach for the preparation of latter system led to the triazine derivatives 5a-f while a new bicyclic triazepine structure 6 is accomplished with difficulty. In expanding the pyridotriazine structure, we obtained derivatives of a new tricyclic structure, 5-substituted-6a-ethyloxycarbonyl-5,6,6a,7-tetrahydropyrido2,3-e]pyrrolo2,1-c]1,2,4]triazin-9(8H)-ones 8 in which the triazine ring is fused with a pyrrole nucleus. Compounds 5a-f and 8a,b will be tested as potential CNS depressant, antiinflammatory, analgesic and antibacterial agents.