Ethanamine, 2,2,2-trifluoro- → N-methyl-N-((1R)-2-phenyl-1-((2,2,2-trifluoroethyl)carbamoyl)ethyl)carbamic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

At 0° C., N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (2.18 g, 11.4 mmol) was added to a solution of (2R)-2-(N-(tert-butoxycarbonyl)-N-methylamino)-3-phenylpropionic acid (3.0 g, 11.4 mmol) and 1-hydroxybenzotriazole hydrate (1.54 g, 11.4 mmol) in N,N-dimethylformamide (2 ml) and dichloromethane (4 ml). The reaction mixture was stirred for 15 min at 0° C. 2,2,2-Trifluoroethylamine (0.91 ml, 11.4 mmol) and ethyldiisopropylamine (2.0 ml, 11.39 mmol) were added successively. The reaction mixture was stirred for 16 h, while it was warming up to room temperature. It was diluted with ethyl acetate (150 ml) and washed with 10% aqueous sodium hydrogen sulfate solution (200 ml). The aqueous phase was extracted with ethyl acetate (2×30 ml). The combined organic layers were washed with saturated sodium hydrogen carbonate solution (150 ml) and dried over magnesium sulfate. The solvent was removed in vacuo. The crude product was purified by flash chromatography on silica (240 g), using ethyl acetate/heptane 1:2 as eluent, to give 3.52 g of N-methyl-N-((1R)-2-phenyl-1-((2,2,2-trifluoroethyl)carbamoyl)ethyl)carbamic acid tert-butyl ester.

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