Hydrochloric Acid → (R)-3-(3-ethoxycarbonyl-4-methyl-phenyl)-piperidine-1-carboxylic acid 4-trifluoromethyl-benzyl ester

Participants

Reaction Steps

(R)-Ethyl 5-(3-piperidinyl)-2-methylbenzoate-D-tartaric acid (2.02 g, 5.08 mmol) was dissolved in 100 mL ethyl acetate and washed with 100 mL saturated aqueous NaHCO3. The organic phase was dried over Na2SO4 and concentrated under reduced pressure. The resultant oil was taken up in 10 mL toluene and imidazole-1-carboxylic acid 4-trifluoromethyl-benzyl ester (1.37 g, 5.08 mmol) was added. The reaction was stirred for 72 h at room temperature under nitrogen. The reaction was diluted with water (200 mL), acidified with 1N aqueous hydrochloric acid and extracted with diethyl ether (2×150 mL). The organic extracts were combined, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resultant oil was flash chromatographed with 10% ethyl acetate/hexanes to yield 2.12 g (93%) of the desired (R)-3-(3-ethoxycarbonyl-4-methyl-phenyl)-piperidine-1-carboxylic acid 4-trifluoromethyl-benzyl ester as a clear oil.

Provenance & Evidence