Methanol → 4,4-Dimethoxy-2-[(4-methoxyphenyl)methyl]-1,3,3-trimethylpiperidine
Reaktionsgleichung
B(F)(F)F.C[CH2:6][O:7]CC.[CH3:10][O:11][C:12]1[CH:28]=[CH:27][C:15]([CH2:16][CH:17]2[C:22]([CH3:24])([CH3:23])[C:21](=[O:25])[CH2:20][CH2:19][N:18]2[CH3:26])=[CH:14][CH:13]=1.[OH-].[Na+].[CH3:31]O>>[CH3:31][O:25][C:21]1([O:7][CH3:6])[CH2:20][CH2:19][N:18]([CH3:26])[CH:17]([CH2:16][C:15]2[CH:14]=[CH:13][C:12]([O:11][CH3:10])=[CH:28][CH:27]=2)[C:22]1([CH3:24])[CH3:23]Komponenten
5
Versuchsvorschrift
40 ml of borontrifluoride etherate are added drop-wise over 20 minutes and with stirring to a solution of 52.2 g (0.2 Mol) 2-(4-methoxybenzyl)-1,3,3-trimethyl-4-piperidone in 500 ml methanol, the temperature being maintained below 35° C. After stirring for 16 hours at room-temperature 40 g pulverized sodium hydroxide are added. After stirring for a further 30 minutes the obtained sodium salts are filtered off and washed with methanol. The filtrate is evaporated under reduced pressure and after addition of 500 ml water, extracted 3 times with 150 ml of chloroform. The chloroform phases are dried over sodium sulphate and evaporated under reduced pressure. After crystallization from 200 ml petrol ether (b.p.: 60°-80° C.) and further recrystallization there are obtained 25.4 g 4,4-dimethoxy-2-(4-methoxybenzyl)-1,3,3-trimethylpiperidine, m.p.: 91°-92.5° C.