Synthesis of Pyrrolo[1′,2′:1′,2′]Pyrazino-[6′,5′:4,5]Thieno[2,3-c]Pyridazine Derivatives and Related Pentacyclic Heterocycles

Abstract

Abstract Ethyl-5-amino-3,4-diphenylthieno[2,3-c]pyridazine-6-carboxylate(1) was converted into ethyl 3,4-diphenyl-5-(1-pyrrolyl)-thieno[2,3-c]pyridazine-6-carboxylate(2). Several derivatives of the latter compound have been synthesized. Also, the synthesis of 3,4-diphenylpyrrolo[1″,2″:1′,2′]pyrazino[6′,5′:4,5]-thieno[2,3-c]pyridazines and other related fused heterocycles are described.