N,N'-Dicyclohexylurea → 2-Benzyloxy-5-fluoro-3-(2,2,2-trifluoroethylcarbamoyl)-benzoic acid-[2-hydroxy-2-(2,2-dimethyl-1,3-dioxolan-4-yl)-ethylamide]

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Reaction Conditions

Reaction Steps

4.46 g (12 mmol) of 2-benzyloxy-5-fluoro-3-(2,2,2-trifluoroethylcarbamoyl)-benzoic acid is dissolved in 30 ml of dry N,N-dimethylformamide with exclusion of moisture, 1.85 g (12 mmol) of hydroxybenzotriazolel, 2.43 g (15 mmol) of 2-hydroxy-2-(2,2-dimethyl-1,3-dioxolan-4-yl)-ethylamine are added and the solution is cooled to -10° C. 2.68 g (13 mmol) of dicyclohexylcarbodiimide is added by portions to the cooled solution, it is stirred for 1 hour at -10° C. and 6 hours at room temperature. The precipitate of the dicyclohexylurea is then suctioned off, the filtrate is evaporated to dryness in a vacuum and the residue is dissolved in about 100 ml of ethyl acetate. The solution is shaken out with saturated bicarbonate solution and with water, dried on sodium sulfate, filtered and concentrated by evaporation and chromatographed on silica gel 60 (Merck) with ethyl acetate/hexane. 4.22 g (8.2 mmol)=68.3% of the theoretical yield of the compound is obtained as an amorphous solid.

Provenance & Evidence