1-Aminocyclohexanecarboxylic acid → 2-Cyclopentyl-3-oxa-1-azaspiro[4.5]dec-1-en-4-one

Beteiligte Stoffe

Reaktionsschritte

1.98 g (15 mmol) of cyclopentanecarbonyl chloride was added to a solution of 2.16 g (15 mmol) of 1-aminocyclohexanecarboxylic acid and 4.8 g (45 mmol) of sodium carbonate in 50 ml of ethyl acetate-50 ml of water under ice-cooling. After the mixture was stirred at room temperature overnight, ethyl acetate was added thereto, and the mixture was washed with a 10% aqueous potassium hydrogensulfate solution, a saturated aqueous sodium bicarbonate solution and then saturated brine. After the obtained organic layer was washed with saturated brine, it was dried with anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, methylene chloride was added thereto, and under ice-cooling, 1.59 g (8.3 mmol) of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride was added. After the mixture was stirred at room temperature overnight, under reduced pressure, the reaction solution was concentrated, ethyl acetate was added thereto, and the mixture was successively washed with water, a 10% aqueous potassium hydrogensulfate solution, a saturated aqueous sodium hydrogencarbonate solution and saturated brine, followed by drying with anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to obtain 1.41 g (42%) of the title compound.

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