Diversity-Oriented Synthesis of Imidazo-Dipyridines with Anticancer Activity via the Groebke-Blackburn-Bienaymé and TBAB-Mediated Cascade Reaction in One Pot.

A facile and metal-free one-pot protocol for the synthesis of fused imidazopyridine scaffolds has been developed. This novel protocol combines the Groebke-Blackburn-Bienaymé reaction (GBBR) with a sequential TBAB-mediated cyclization cascade. Biological evaluation demonstrated that compound 6a inhibits human prostate cancer cell DU-145 proliferation with an IC50 of 1.6 µM. The molecular mechanism study indicates that 6a significantly suppresses the oncogenic Erk kinase phosphorylation at 3 µM.