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4-Hydroxycoumarin derivatives are of interest because of their physiological, photodynamic, anticoagulant, spasmolytic, bacteriostatic, and rodenticidal activities. Some coumarin derivatives are known for their antibiotic and antifungal activities. They are also used as analytical reagents. The most widely used antithrombotic in USA and Canada is racemic sodium Warfarin. It is possible to obtain compounds with good biological activity, but with lower toxicity and fewer side effects, by chemical modifications of the Warfarin structure. The title compound, (4-(4-fluorophenyl)-2-hydroxy-2-methyl3,4-dihydropyrano[3,2-c]chromen-5(2H)-one, (Fig. 1), was synthesized from 4-hydroxycoumarin (3.56 g, 22 mmol) and 4(4-fluorophenyl)-3-buten-2-one (3.63 g, 22 mmol) and water. The reaction mixture was refluxed for 21 h. After cooling, the product crystallized out and was filtered off. The product was recrystallized from acetonitrile; yield, 2.86 g (40%), m.p. 164 – 165.5 ̊C. Colourless prisms, suitable for X-ray diffraction analysis, were grown by slow evaporation of an ethyl acetate solution. Xray data were collected at room temperature with an EnrafNonius KappaCCD diffractometer using graphitemonochromated Mo-Ka (l = 0.71069 Å) radiation, and monitored by COLLECT.1 Crystal unit-cell and orientation parameters were obtained from an auto-indexing procedure, as implemented in DENZO-HKL2000.2 Intensities recorded up to a diffraction angle, q of 25 ̊ were also integrated with DENZO, scaled, and then reduced using SCALEPACK-HKL2000,2 after post-refinement of the unit-cell parameters and absorption X-ray Structure Analysis Online

Crystal Structure of (4-(4-Fluorophenyl)-2-hydroxy-2-methyl-3,4-dihydropyrano[3,2-c]chromen-5(2H)-one