One-Pot Synthesis of Thieno[3,2-e]pyrrolo[1,2-a]pyrimidine Derivative Scaffold: A Valuable Source of PARP-1 Inhibitors.

A new, efficient, and versatile one-pot cascade reaction of diverse Gewald's aminothiophenes, 2-hydroxy-4-oxobut-2-enoic acid, and derivatives of cyanoacetic acid catalyzed by Et3N is presented. It enables direct synthesis of diverse 1-(2-oxoethylidene)-2-oxothieno[3,2-e]pyrrolo[1,2-a]pyrimidine in good to excellent yields. The reaction exhibits a broad substrate scope and also presents an opportunity for further modification of the structure. The method offers a convenient practical alternative to the known procedures. The synthesized thieno[3,2-e]pyrrolo[1,2-a]pyrimidine scaffold is an important structural motif of new poly(ADP-ribose) polymerase (PARP) inhibitors, playing a useful role in multiple pharmacological applications.