反应详情

To a solution of sodium ethoxide obtained from 15.2 g (0.661 mol) of sodium and 540 ml of dry ethanol 115 g (0.658 mol) of diethyl methylmalonate was added. This mixture was stirred for 15 min; then, 184 g (0.659 mol) of 1-bromo-2-(bromomethyl)-4-methoxybenzene was added with vigorous stirring at such a rate to maintain gentle reflux. This mixture was refluxed for an additional 2 h and then cooled to room temperature. A solution of 130 g of KOH in 400 ml of water was added. The resulting mixture was refluxed for 4 h to saponificate the formed ester. Ethanol and water were distilled off until the vapor temperature reached 95° C. To the residue cooled to room temperature 1500 ml of water and then 12 M HCl (to pH 1) were added. The formed precipitate of (2-bromo-5-methoxybenzyl)(methyl)malonic acid was filtered off, washed with 2×200 ml of cold water, and dried on air. Decarboxylation of the substituted methylmalonic acid at 180° C. gave 152 g (84%) of the title product.

1. additionwas added
2. stirringwith vigorous stirring at such a rate
3. temperatureto maintain gentle reflux
4. temperatureThis mixture was refluxed for an additional 2 h
5. temperatureThe resulting mixture was refluxed for 4 h
6. distillationEthanol and water were distilled off until the vapor temperature
7. customreached 95° C
8. temperatureTo the residue cooled to room temperature 1500 ml of water
9. addition12 M HCl (to pH 1) were added
10. filtrationThe formed precipitate of (2-bromo-5-methoxybenzyl)(methyl)malonic acid was filtered off
11. washwashed with 2×200 ml of cold water
12. customdried on air