[CH:1]([O:4][C:5]1[CH:10]=[CH:9][C:8]([CH:11](O)[CH3:12])=[CH:7][CH:6]=1)([CH3:3])[CH3:2].P(Cl)(Cl)(Cl)=O.[Cl-].[Na+].CN(C)[CH:23]=[O:24]>>[CH:1]([O:4][C:5]1[CH:10]=[CH:9][C:8](/[CH:11]=[CH:12]/[CH:23]=[O:24])=[CH:7][CH:6]=1)([CH3:3])[CH3:2]A solution of 1-(4-isopropyloxy phenyl) ethanol of formula 4 (4.8 g, 27 mmol) in dimethyl formamide (10 ml) is slowly added to phosphorus oxychloride (8 ml) in DMF (12 ml) with stirring at 0° C. The reaction mixture is stirred for 2 hours then allowed attaining room temperature followed by heating on an oil bath for 36 hour at 40° C. After the completion of the reaction as monitored by TLC, contents of the reaction mixture are poured into ice cold water (500 ml), neutralised with dilute alkali solution and saturated by adding sodium chloride. The aqueous portion is extracted with ethyl acetate (3×100 ml), organic layer washed with water, dried over anhydrous sodium sulphate and stripped off the solvent under vacuum to furnish crude product (4.8 g). It was purified by column chromatography over silica gel to yield a semisolid 3-(4-isopropyloxy phenyl)-2E-propenal of formula 3 (80%).
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