反应详情

2,4-dihydroxylbenzaldehyde (0.27 g, 2 mmol) and di-tert-buty malonic acid (0.43 g, 2 mmol) are dissolved in tert-butanol (5 mL), and three drops of piperidine are added. The mixture is refluxed for 16 hours to obtain a suspension. After being placed for cooling, insoluble material is removed by filtrating. The mother liquor is concentrated, and the ethyl acetate is added with stirring. The supernatant is separated, concentrated, and chromatographed over silica gel column with petroleum/ethyl acetate (3:4) as eluent to obtain 0.14 g of 7-hydroxyl-3-coumarin carboxylic acid tert-butyl ester, yield: 22.5%.

1. temperatureThe mixture is refluxed for 16 hours
2. customto obtain a suspension
3. temperaturefor cooling
4. custominsoluble material is removed
5. filtrationby filtrating
6. concentrationThe mother liquor is concentrated
7. additionthe ethyl acetate is added
8. customThe supernatant is separated
9. concentrationconcentrated
10. customchromatographed over silica gel column with petroleum/ethyl acetate (3:4) as eluent