反应详情

25 g (0.13 mol) of (E)-4-hydroxy-3-methoxycinnamic acid were dissolved in 180 ml of methanol and 5 ml of concentrated sulfuric acid was added. The solution was refluxed for 2 hours. Thereafter, the major part of the methanol (about 150 ml) was distilled off and the residue was poured onto 500 ml of ice water. The precipitated ester was filtered off with suction, washed in succession with cold water, with a little cold NaHCO3 solution and again with cold water and dried at 50° C. under reduced pressure from a water-jet pump. Chromatography over 250 g of silica gel using dichloromethane/diethyl ether (19:1) gave 21.78 g of methyl (E)-4-hydroxy-3-methoxycinnamate as a pale yellow oil.

1. temperatureThe solution was refluxed for 2 hours
2. distillationThereafter, the major part of the methanol (about 150 ml) was distilled off
3. additionthe residue was poured onto 500 ml of ice water
4. filtrationThe precipitated ester was filtered off with suction
5. washwashed in succession with cold water, with a little cold NaHCO3 solution and again with cold water
6. dry with materialdried at 50° C. under reduced pressure from a water-jet pump