Synthesis and biological evaluation of novel substituted pyrrolo[1,2- a ]quinoxaline derivatives as inhibitors of the human protein kinase CK2

Herein we describe the synthesis and properties of substituted phenylaminopyrrolo[1,2- a ]quinoxaline-carboxylic acid derivatives as a novel class of potent inhibitors of the human protein kinase CK2. A set of 15 compounds was designed and synthesized using convenient and straightforward synthesis protocols. The compounds were tested for inhibition of human protein kinase CK2, which is a potential drug target for many diseases including inflammatory disorders and cancer. New inhibitors with IC 50 in the micro- and sub-micromolar range were identified. The most promising compound, the 4-[(3-chlorophenyl)amino]pyrrolo[1,2- a ]quinoxaline-3-carboxylic acid 1c inhibited human CK2 with an IC 50 of 49 nM. Our findings indicate that pyrrolo[1,2- a ]quinoxalines are a promising starting scaffold for further development and optimization of human protein kinase CK2 inhibitors.