反应详情

Methyl 3-hydroxybenzoate (75.5 g) is dissolved in trifluoroacetic acid (2 L), thereto is added hexamethylenetetramine (141.4 g) at room temperature and the mixture is heated under reflux for 3 hours. The reaction solution is concentrated under reduced pressure, to the resulting residue is added water, the mixture is adjusted to pH 8 with potassium carbonate and sodium hydrogen carbonate, diluted with water and extracted with ethyl acetate. The organic layer is washed with saturated brine, dried over sodium sulfate and evaporated to remove the solvent under reduced pressure. The resulting residue is purified by silica gel column chromatography (eluent: hexane/ethyl acetate=8/1, 5/1 followed by 2/1) to give methyl 2-formyl-3-hydroxybenzoate (54.6 g) (ESI-MS m/z: 179[M−H]−) and methyl 4-formyl-3-hydroxybenzoate (4.4 g)

1. temperaturethe mixture is heated
2. temperatureunder reflux for 3 hours
3. concentrationThe reaction solution is concentrated under reduced pressure, to the resulting residue
4. additionis added water
5. additiondiluted with water
6. extractionextracted with ethyl acetate
7. washThe organic layer is washed with saturated brine
8. dry with materialdried over sodium sulfate
9. customevaporated
10. customto remove the solvent under reduced pressure
11. customThe resulting residue is purified by silica gel column chromatography (eluent: hexane/ethyl acetate=8/1, 5/1 followed by 2/1)