Design, synthesis and structure--activity relationship (SAR) studies of imidazo[4,5-b]pyridine derived purine isosteres and their potential as cytotoxic agents.

Drug resistance to chemotherapeutic agents paved the way to develop novel synthetic molecules which are active on MDR cancer cell lines. Regio-isomeric imidazo[4,5-b]pyridine analogues were synthesized and evaluated for their cytotoxic activity against a range of cancer cell lines. The structure-activity relationship (SAR) studies of the imidazopyridine analogues are also described. Analogue 6b displayed strong cytotoxicity and good microsomal stability.