To a solution of 2,4,5-trifluorobenzoic acid ethyl ester (Example 1e, 14.8 g, 72.4 mmol) in acetonitrile (225 mL) is added triethylamine (65 mL, 466 mmol) and pyrrolidin-3-ylcarbamic acid tert-butyl ester (16.07 g, 86.2 mmol). After 45 hours, the reaction mixture is diluted with ethyl acetate and washed with saturated NaHCO3, water, and brine. The organic layer is dried over MgSO4, filtered, and the filtrate is concentrated to afford an oil. The resulting residue is purified by flash chromatography (1:5 ethyl acetate/hexanes) to afford the title compound. MS (ES, M+1) m/z 371, mp 98–100° C.
