Cascade Regioselective Heterocyclization of 2-Acyl-1,1,3,3-tetracyanopropenides: Synthesis of Pyrrolo[3,4-c]pyridine and Pyrrolo[3,4-d]thieno[2,3-b]pyridine Derivatives
les. The involvement of methyl mercaptoacetate to this reaction leads to the formation of the methyl 4,8-diamino-1-aryl-1-hydroxy-3-oxo-2,3-dihydro-1 H -pyrrolo[3,4- d ]thieno[2,3- b ]pyridine-7-carboxylates, containing a newfused heterocyclic scaffold.