Potassium Hydroxide → 3-(2-Bromo-5-methoxyphenyl)-2-methylpropanoic acid
Reaktionsgleichung
[Br:1][C:2]1[CH:7]=[CH:6][C:5]([O:8][CH3:9])=[CH:4][C:3]=1[CH2:10]Br.[OH-:12].[K+]>O>[Br:1][C:2]1[CH:7]=[CH:6][C:5]([O:8][CH3:9])=[CH:4][C:3]=1[CH2:10][CH:4]([CH3:3])[C:5]([OH:8])=[O:12]Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
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.