Synthesis and Pharmacological Investigations of Some 4‐Hydroxycoumarin Derivatives

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 with respect to warfarin, showed that the compounds have anticoagulant activity. Compounds 4-hydroxy-3-[1-phenyl-2-(4'-chlorobenzoyl)ethyl]-2H-1-benzopyran-2-one 2b, 4-hydroxy-3-[1-(4-fluorophenyl)-3-oxobutyl]-2H-1-benzopyran-2-one 3a, and 3, 3'-p-bromobenzylidene-bis-(4-hydroxy-2H-1-benzopyran-2-one) 4b showed slight acute toxicity and a greater anticoagulant effect than warfarin.