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.