A solution of trichloroacetyl chloride (11.1 ml, 99 mmol) in toluene (30 ml) was added dropwise over 45 minutes to a stirred, ice-cooled solution of 4-methoxybenzyl alcohol (12.4 ml, 99 mmol) and N,N-dimethylaniline (12.6 ml, 99 mmol) in toluene (100 ml). The cooling bath was removed and stirring continued at room temperature for 1.5 hours, then the reaction mixture was filtered to remove the N,N-dimethylaniline hydrochloride which was washed with toluene (30 ml). A stirred mixture of the combined filtrate and washings, ethyl 3-piperidinecarboxylate (14.0 ml, 90 mmol) and anhydrous potassium carbonate (13.7 g, 99 mmol), under nitrogen, was heated under reflux for 110 hours, allowed to cool and filtered. Evaporation of the filtrate under reduced pressure gave a brown oil which was dissolved in dichloromethane (100 ml) and the resulting solution washed successively with 2M aqueous sodium carbonate solution (100 ml) and ca. 5M hydrochloric acid (200 ml), dried (Na2SO4) and evaporated under reduced pressure to provide a viscous oil. This oil was stirred at room temperature with a 1:1 mixture of ethyl acetate:hexane (100 ml) to produce a solid which was purified by successive trituration with the same solvent mixture (4×50 ml) to afford the title compound (6.11 g). Rf 0.85 (SS 1). Found: C,59.41; H,7.50; N,4.15. C16H23NO3 ; HCl; 0.50 H2O requires C,59.52; H,7.80; N,4.34%
