Synthesis of dipyrrolo[3,4-a:3,4-c]carbazoles: new kinase inhibitors

Abstract Two dipyrrolo[3,4- a :3,4- c ]carbazole stereoisomers were unexpectedly obtained by Diels–Alder dimerization of 3-indolylmaleimide. Three dimensional structures of both stereoisomers were confirmed by X-ray analysis. Moreover compound 4 inhibits protein kinases in vitro, especially Pim-3, in the sub-micromolar range.