Methanol → 4-Methoxycinnamate methyl ester

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Reaktionsschritte

A homogeneous mixture containing 4-methoxycinnamaldehyde (7.5 mmol), DDQ (11.3 mmol), MeOH (15 mL) and toluene (10 mL) is taken in a round bottom flask and catalytic amount of AMBERLITE® IR 400 (0.1 g) is added to it. The mixture is refluxed for 6 hrs under Dean Stark apparatus. After completion of the reaction (observed by TLC and by GC analysis), the reaction mixture is filtered and washed with MeOH (5 ml×2). Concentrate the filtrate under reduced pressure and the crude product thus obtained is loaded on a neutral alumina column and eluted with diethyl ether. Methyl 4-methoxycinnamate (from formula I where X1═H, X2═H, X3═OCH3, X4═H, X5═H, R═CH3) is isolated in 91% yield. 1H-NMR (CDCl3, 300 MHz) δ7.56 (1H, d, J=16.55 Hz), 7.37 (2H, d), 6.80 (2H, d), 6.22 (1H, d, J=16.55 Hz), 3.73 (3H, s), 3.70 (3H, s); 13C-NMR (CDCl3, 75.4 MHz) δ167.7, 161.4, 144.5, 129.7, 127.1, 115.2, 114.3, 55.3, 51.5.

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