反应详情

411 ml of a 2M solution of the sodium salt of hexamethyldisilazane in THF are cooled to −60° C., under a nitrogen atmosphere, 350 ml of THF are added, followed dropwise by a solution of 67.7 g of 2,4-dichlorophenylacetic acid in 70 ml of THF and the mixture is kept stirred for 2 hours while the temperature is maintained below −40° C. 53.5 g of methyl 4-chlorobenzoate are then added dropwise and at −60° C. and the mixture is kept stirred while the temperature is allowed to rise to 10° C. The reaction mixture is poured over an ice/1 liter 2N HCl mixture, the organic phase is washed with a saturated NaHCO3 solution, with water, extracted with ether, the organic phase is dried over Na2SO4 and the solvent is evaporated under vacuum. The residue is taken up in pentane and the crystallized product formed is drained. 70 g of the expected compound are obtained.

1. temperatureis maintained below −40° C
2. stirringthe mixture is kept stirred while the temperature
3. customto rise to 10° C
4. washthe organic phase is washed with a saturated NaHCO3 solution, with water
5. extractionextracted with ether
6. dry with materialthe organic phase is dried over Na2SO4
7. customthe solvent is evaporated under vacuum
8. customthe crystallized product formed