Potassium Hydroxide → Brofaromine

Reaktionsgleichung

[Br:1][C:2]1[C:10]2[O:9][C:8]([CH:11]3[CH2:16][CH2:15][N:14](C(OCC)=O)[CH2:13][CH2:12]3)=[CH:7][C:6]=2[CH:5]=[C:4]([O:22][CH3:23])[CH:3]=1.[OH-].[K+]>C(O)CO.C1(C)C=CC=CC=1>[Br:1][C:2]1[C:10]2[O:9][C:8]([CH:11]3[CH2:12][CH2:13][NH:14][CH2:15][CH2:16]3)=[CH:7][C:6]=2[CH:5]=[C:4]([O:22][CH3:23])[CH:3]=1

Komponenten

Versuchsvorschrift

7.6 g of 4-(7-bromo-5-methoxy-benzofuran-2-yl)-1-ethoxycarbonyl-piperidine are dissolved in 80 ml of ethylene glycol. After the addition of 19.4 g of 86% potassium hydroxide, the resulting cloudy solution is heated at 160° with vigorous stirring for 18 hours. The reaction mixture is cooled to 100°, diluted with 80 ml of toluene, and cooled further to 20°. The reaction solution is extracted twice with 1000 ml of water each time and then four times with 200 ml of a 10% solution of methanesulfonic acid in water each time. The resulting solution in methanesulfonic acid is adjusted to pH 12 by the addition of 30% sodium hydroxide solution and extracted by shaking with 1000 ml of chloroform. The chloroform solution is dried over sodium sulfate, filtered and concentrated by evaporation. Crystallisation from ethyl acetate yields 4-(7-bromo-5-methoxybenzofuran-2-yl)-piperidine having a melting point of 149°-152°. There is obtained from the base by treatment with methanolic hydrochloric acid and recrystallisation from methanol/ether 4-(7-bromo-5-methoxy-benzofuran-2-yl)-piperidine-hydrochloride having a melting point of 242°-243°.