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 structureeactivity
relationship (SAR) studies of the imidazopyridine analogues are also described. Analogue 6b displayed
strong cytotoxicity and good microsomal stability.