Certain coumarin α-methylene-γ-butyrolactones were synthesized and evaluated for antiproliferative and vasorelaxing activities. These compounds were synthesized via alkylation of hydroxycoumarins 2a–f followed by oxidation and the Reformatsky-type condensation. The results of this study are as follows (1) for the vasorelaxing activity, coumarin-7-yl α-methylene-γ-butyrolactone 6d, with an IC50 value of 9.4 μM against pig ...