反应详情

A mixture of 4-methoxy phenylpropane (2 g), silica gel (0.5-0.8 g), DDQ (7.5 g) and dioxane (5-8 ml) was taken in a 100 ml Erlenmeyer flask fitted with a loose funnel at the top. The flask was placed inside a microwave oven operating at medium power (600 W) and irradiated for 2-8 minutes. After completion of the reaction (monitored by TLC), the contents of the flask were poured into chloroform and passed through a bed of Celite and further washed with chloroform. The filtrate and washing were combined and the chloroform layers were washed with an aqueous NaOH (15%, 3×15 ml). The combined aqueous layers were further extracted with chloroform (3×15 ml). The chloroform layers were then combined and washed with saturated sodium chloride (3×15 m), dried over anhydrous sodium sulphate and filtered. The solvent was removed to afford a crude product which was loaded on silica column and the column was first eluted with hexane (70-80 ml) and then with an increasing amount of hexane/ethyl acetate (9:1 to 1:9). The fractions were monitored on TLC plate and the desired fractions were combined and solvent was removed under vacuum to afford 4-methoxy cinnamaldehyde in 68% yield as a solid; mp 57-58° C.; (lit. mp 58° C.). The physical and spectral data was found to similar as reported.

1. customfitted with a loose funnel at the top
2. customThe flask was placed inside a microwave oven
3. customoperating at medium power (600 W) and irradiated for 2-8 minutes
4. customAfter completion of the reaction (monitored by TLC)
5. washfurther washed with chloroform
6. washThe filtrate and washing
7. washthe chloroform layers were washed with an aqueous NaOH (15%, 3×15 ml)
8. extractionThe combined aqueous layers were further extracted with chloroform (3×15 ml)
9. washwashed with saturated sodium chloride (3×15 m)
10. dry with materialdried over anhydrous sodium sulphate
11. filtrationfiltered
12. customThe solvent was removed
13. customto afford a crude product which
14. washthe column was first eluted with hexane (70-80 ml)
15. customsolvent was removed under vacuum