Ethyl Acetate → rac-ethyl (1R,2S)-1-amino-2-ethenylcyclopropane-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

498.4 g (content: 484.49 g, 1.48 mol) out of the (1R,2S)-1-amino-1-ethoxycarbonyl-2-vinylcyclopropane p-toluenesulfonate obtained in Example 29 and 2.1915 kg of ethyl acetate were added into a 10-L separable flask, and the obtained mixture was then cooled to 6° C. To this mixture, a potassium bicarbonate aqueous solution consisting of 220.04 g (2.2259 mol) of potassium bicarbonate and 971.7 g of water was added dropwise over 20 minutes, so as to separate (1R,2S)-1-amino-1-ethoxycarbonyl-2-vinylcyclopropane. The mixture was stirred for 1 hour, while maintaining the temperature at 6° C., so that an ethyl acetate layer was separated. To a water layer, 48.54 g of sodium chloride and 876.8 g of ethyl acetate were added, and the obtained mixture was then stirred at 6° C. for 1 hour 20 minutes. Thereafter, an ethyl acetate layer was separated. After this operation, 438.3 g of ethyl acetate was added to the obtained water layer, the obtained mixture was then stirred at 26° C. for 1 hour, and an ethyl acetate layer was then separated. This operation was repeatedly carried out three times. All of the ethyl acetate layers were gathered in a 10-L separable flask, and the gathered layer was then cooled to 6° C. Then, 121.47 g of sodium sulfate was added thereto, and the obtained mixture was then stirred for 30 minutes. The sodium sulfate was then removed by filtration. The sodium sulfate was washed with 438.3 g of ethyl acetate, and the washing solution was then mixed with the filtrate, so as to obtain an ethyl acetate solution of (1R,2S)-1-amino-1-ethoxycarbonyl-2-vinylcyclopropane. As a result of analysis by HPLC, the content of the (1R,2S)-1-amino-1-ethoxycarbonyl-2-vinylcyclopropane was found to be 212.86 g (yield: 95.1%).

Provenance & Evidence