Ethyl 4-oxo-1-piperidinecarboxylate → HCID 22111104, compound

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Reaction Steps

In a reactor equipped with a water trap, a solution of 3,3-diphenylpropylamine (4.9 g) and 1-ethoxycarbonyl-4-piperidone (4.0 g) in toluene (100 mL) was refluxed for 2 hours. This reaction mixture was concentrated under reduced pressure and the residue was dissolved in 80 mL of ethanol. After this solution was cooled with ice, 1.8 g of sodium cyanoborohydride and a small amount of bromocresol green were added. Then, 4N-hydrogen chloride solution in ethanol was added dropwise until the reaction mixture had turned yellow and, after completion of dropwise addition, the mixture was further stirred for 30 minutes. This reaction mixture was poured into an excess of aqueous sodium hydrogen carbonate and extracted with ethyl acetate. The extract was washed with saturated aqueous NaCl, dried over MgSO4, and concentrated under reduced pressure to give ethyl 4-[(3,3-diphenylpropyl)amino]-1-piperidinecarboxylate. This product was dissolved in 80 mL of N,N-dimethylformamide, followed by addition of 2.8 mL of benzyl bromide and 3.2 g of potassium carbonate, and the mixture was stirred at room temperature for 2 hours. This reaaction mixture was diluted with water and extracted with ethyl acetate. The extract was washed with saturated aqueous NaCl, dried over MgSO4, and concentrated. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=9:1 to 7:3 ) to provide 7.8 g of the title compound. Yield based on 3,3-diphenylpropylamine was 73%.

Provenance & Evidence