Ethyl 1-benzyl-3-oxopiperidine-4-carboxylate hydrochloride → HCID 178517783, compound

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Reaction Steps

To a solution of sodium ethoxide, prepared from 3.2 g (133 mmol) of sodium metal and 200 mL of absolute ethanol, at ambient temperature was added 8.3 g (74 mmol) of trifluoroacetamidine followed by 17.8 g (60 mmol) of ethyl 1-benzyl-3-oxopiperidine-4-carboxylate hydrochloride in portions over 15 min. The reaction mixture was stirred at ambient temperature for 1 h, then heated at reflux for 30 h. The mixture was concentrated in vacuo. The resultant red foam was partitioned between 300 mL of 1N aqueous sodium hydroxide solution and 300 mL of ether. The aqueous layer was washed with 300 mL of diethyl ether and the combined ether phases were extracted with 50 mL of 1N aqueous sodium hydroxide solution. The combined aqueous phases were cooled in an ice-water bath and neutralized to pH 7 with concentration hydrochloric acid. The solids were collected, washed with water, and dried in vacuo to give the title compound as a beige solid, which was used as is in Step B below. An analytical sample was prepared by recrystallization from isopropanol to give the title compound as a white powder.

Provenance & Evidence