反应详情

413 ml of a 2M solution of the sodium salt of hexamethyldisilazane in THF are cooled to −65° C., under a nitrogen atmosphere, 300 ml of THF are added, followed dropwise by a solution of 55 g of 4-methoxyphenylacetic acid in 70 ml of THF and the mixture is kept stirred for 3 hours at a temperature of less than −45° C. 64.5 g of methyl 2,4-dichlorobenzoate are then added dropwise and the mixture is kept stirred while the temperature is allowed to rise to 0° C. The reaction mixture is poured over an ice/1 liter 2N HCl mixture, extracted with ether, the organic phase is washed with a saturated NaHCO3 solution, dried over Na2SO4 and the solvent is evaporated under vacuum. The residue is chromatographed on silica gel, eluted with heptane and then with the heptane/AcOEt mixture to (90/10; v/v). 29 g of the expected compound are obtained.

1. stirringthe mixture is kept stirred while the temperature
2. customto rise to 0° C
3. extractionextracted with ether
4. washthe organic phase is washed with a saturated NaHCO3 solution
5. dry with materialdried over Na2SO4
6. customthe solvent is evaporated under vacuum
7. customThe residue is chromatographed on silica gel
8. washeluted with heptane