A series of selenophene derivatives 3 were synthesized as potential CHK1 inhibitors. The effects of substitution on the 4′-or 5′-position of selenophene moiety and shifting the hydroxyl group position on C6-phenolic ring of oxindole were explored. This study led to the discovery of the most potent CHK1 inhibitors 29–33 and 39–43, which had IC50 values in the subnanomolar range.
