反应详情

A solution of 20 g (0.112 mole) of 4-methyl-2-piperidinecarboxylic acid hydrochloride, 24 g (0.224 mole) of benzyl alcohol and 25.6 g (0.134 mole) of p-toluenesulfonic acid monohydrate in 100 ml of benzene was refluxed for 5 hours with the continuous removal of water through a Dean-Stark water trap. At the end of this period, the solvent was distilled off, and the residue was washed with ether-n-hexane and recrystallized to give 10 g (22%) of benzyl 4-methyl-2-piperidinecarboxylate p-toluenesulfonate, M.P. 160°-163° C. The following 2-piperidinecarboxylates not previously reported in the chemical literature were synthesized by the aforementioned procedure.

1. distillationAt the end of this period, the solvent was distilled off
2. washthe residue was washed with ether-n-hexane
3. customrecrystallized