Synthesis of 2,4-diaryl chromenopyridines and evaluation of their topoisomerase I and II inhibitory activity, cytotoxicity, and structure-activity relationship.

Designed and synthesized were a series of 5H-chromeno[4,3-b]pyridines with substitution at 2- and 4-positions with various 5- or 6-membered heteroaromatics as antitumor agents. They were evaluated for topoisomerase I and II inhibitory activities as well as cytotoxicities against several human cancer cell lines. Structure-activity relationship study showed that 2-furyl or 2-thienyl at 2- or 4-position of central pyridine is crucial in displaying topo I or II inhibitory activity and cytotoxicity.