| abstract |
The invention relates to a process for the preparation of 1,2,4,5-tetra-alkyl-4-aryl-piperidines, which are suitable for influencing the central nervous system and can be used as an analgesic. For example, 1,2,4,5-tetramethyl-4- (3-methoxyphenyl) -piperidine is prepared by adding 1,4,5-trimethyl-4- (3-methoxyphenyl) -3,4,5,6-tetrahydropyridinium tetrafluoroborane reacted with a 1.6 molar solution of methyllithium in diethyl ether. After verduennen the reaction mixture with ammonium chloride solution, the organic layer is separated. |