Diversity-oriented decoration of pyrrolo[1,2-a]pyrazines

Diversity-oriented synthesis of a chemical library based on a pyrrolo1,2-a]pyrazine core is described by using palladium-catalyzed direct C6 arylation of pyrrolo1,2-a]pyrazines with various aryl bromides. The starting materials, pyrrolo1,2-a]pyrazines, were easily synthesized by the base-mediated N-alkylation of pyrrole-2-carboxaldehyde with several 2-bromoacetophenones followed by dehydrative cyclization with incorporation of nitrogen by the action of ammonium acetate. Introduction of other functional groups on this chemical scaffold is also discussed herein.