Hydrochloric Acid → 1-Carbethoxy-4-[2-(1-methylethoxy)phenyl]-4-piperidinol

Participants

Reaction Conditions

Reaction Steps

To a suspended solution of Mg chips (10.07 g, 0.414 mol) in anhydrous ether (150 mL) at 22° C. under argon was added ca. 0.15 mL of 1,2-dibromoethane. Then 43.7 g (0.200 mol) of XIV in 200 mL of ether was added dropwise. After 50% of the aryl halide was added, the reaction began to reflux vigorously. The flask was cooled in an ice bath. After the refluxing had subsided somewhat, the ice bath was removed and the remaining aryl halide was added over a 1.5 h period. The resultant Grignard reagent was cooled in a dry ice/ether bath for 2 h and then treated with 34.0 mL (0.221 mol) of 98% 1-carbethoxy-4-piperidone. Upon complete addition of ketone, the reaction mixture was allowed to warm to 22° C. and stirred for 2 h. The reaction was then quenched with cold aqueous ammonium chloride which resulted in an emulsion. Addition of 1M aqueous HCl solution separated the two layers. The aqueous phase was extracted with additional ether and the combined organic solution was washed with 10% aqueous sodium bisulfite, 1.0M HCl, saturated NaHCO3, and dried (K2CO3). Filtration concentration yielded 56.36 g of XV as a yellow viscous oil which was carried on without further purification The structure of this oil was supported by 1H NMR.

Provenance & Evidence