反应详情

温度

50 °C

Diethyl (alpha,alpha-dimethylbenzyl)malonate was prepared by the congugate addition of phenyl magnesium bromide to diethyl isopropylidenemalonate as described by C. Holmberg [Liebigs Ann. Chem., 748 (1981)]. A solution of this diester (42.1 g, 0.15 mole) in ethanol (100 mL) was treated by dropwise addition with a solution of potassium hydroxide (8.48 g, 0.13 mole) in 100 mL of ethanol. After heating at 90° C. for 1 h and at 50° C. for 20 h, the reaction mixture was evaporated on the rotary evaporator to a residue. The residue was diluted with water and extracted with ether to remove unreacted starting material. The aqueous phase was cooled to 5° C., acidified to pH 3, with 6N HCl and extracted with methylene chloride. The organic layer was washed with brine solution and dried over magnesium sulfate. Evaporation of the solvent gave 27.3 g (84%) of liquid product. NMR (CDCl3) 1.05 (3H, t), 1.6 (6H, s), 3.78 (1H, s), 3.96 (2H, m), 7.2-7.4 (5H, m).

1. customthe reaction mixture was evaporated on the rotary evaporator to a residue
2. additionThe residue was diluted with water
3. extractionextracted with ether
4. customto remove unreacted
5. temperatureThe aqueous phase was cooled to 5° C.
6. extractionextracted with methylene chloride
7. washThe organic layer was washed with brine solution
8. dry with materialdried over magnesium sulfate
9. customEvaporation of the solvent