Dicyclohexylcarbodiimide → 2-Propenamide, N-methoxy-N-methyl-2-(trifluoromethyl)-

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16.6 g (167 mmol) of N,O-dimethylhydroxylamine hydrochloride were suspended in 900 ml of CH2Cl2 and 29.1 ml (167 mmol) of N,N-diisopropylethylamine added dropwise at 0° C. The resulting solution was added dropwise to a solution of 20.0 g (143 mmol) of 2-(trifluoromethyl)propenoic acid in 500 ml of CH2Cl2 at −40° C. Afterwards, 34.5 g (167 mmol) of N,N′-dicyclohexylcarbodiimide were added and the mixture stirred at 0° C. for 16 h. The resulting suspension was then filtrated and the filtrate carefully evaporated (the desired product is volatile!). Afterwards, 100 ml of n-pentane were added and the suspension stirred for 30 minutes at ambient temperature. The precipitate was removed by filtration, the filtrate was carefully evaporated. Chromatography on silica gel using ethyl acetate/n-pentane 1:4 yielded 22.8 g of the desired product. Rt=0.56 min (Method P).

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