P(Cl)(Cl)(Cl)=O.[C:6]1([C:12]2[C:17]3[CH:18]=[CH:19][CH:20]=[CH:21][C:16]=3[O:15][CH2:14][CH:13]=2)[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1.O.[OH-].[Na+].CN(C)[CH:27]=[O:28]>C(Cl)Cl.C1CCCCC1>[C:6]1([C:12]2[C:17]3[CH:18]=[CH:19][CH:20]=[CH:21][C:16]=3[O:15][CH2:14][C:13]=2[CH:27]=[O:28])[CH:7]=[CH:8][CH:9]=[CH:10][CH:11]=1
71 ml (0.773 mol) of phosphorus oxychloride are added dropwise to 300 ml of dimethylformamide maintained at 0° C. The reaction mixture is left stirring for 20 minutes at a temperature of between 0 and 5° C. A solution of 16.1 g (77.3 mmol) of 4-phenyl-2H-1-benzopyran in 22.5 ml of dimethylformamide is then added to the reaction mixture. The reaction mixture is allowed to return to room temperature and is then brought to 60° C. for 7 hours. The reaction mixture is then poured into a mixture of ice and water which is neutralized with NaOH. The organic phase is extracted with ethyl acetate and then the organic phase is washed 3 times with water. After drying over anhydrous sodium sulphate, the organic phase is concentrated under reduced pressure. A pasty solid is thus obtained, which solid, after silica column chromatography using a 1/1 methylene chloride/cyclohexane mixture as eluant, results in 15.3 g of the title compound in the form of a yellow solid, the melting point of which is 82-83° C. (yield=83%).
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