Abstract The synthesis of ten coumarin derivatives of 4-hydroxycoumarin and various unsaturated ketones and aldehydes is described. The structures of the synthesized compounds were confirmed by IR, 1 H-NMR, and mass-spectral data. Acute toxicity studies of the compounds were performed on mice by oral and intraperitoneal administration. A comparative pharmacological study of the in vivo anticoagulant effects of the derivatives ...