Commercially available 4-trifluoromethylbenzylamine (1 ml, 7 mmol) was dissolved in 20 ml of AcOEt and at 0° C. triphosgene (2 g, 7 mmol) was added to the solution. The mixture was warmed at 80° C. for 4 hours then evaporated and the residue was dissolved in 5 ml of DMF. The solution of the isocyanate was added dropwise to a solution in DMF (10 ml) of compound 1e (766 mg, 4.66 mmol) and the mixture was warmed at 80° C. for 8 hours. (TLC AcOEt). The solvent was evaporated and the crude was dissolved in AcOEt (30 ml) and washed with water (1×20 ml) and brine. The organic phase was dried over sodium sulfate and concentrated under vacuum. The purification of the crude residue by chromatographic column gave 550 mg of a white solid. Yield=32% 1HNMR (DMSO, 400 MHz) δ 4.40 (2H, d, J=5.6 Hz), 4.52 (2H, s), 6.70 (1H, dd, J=8 Hz, J′=1.2 Hz), 6.86 (2H, t, J=8 Hz), 7.16 (1H, dd, J=8 Hz, J′=1.2 Hz), 7.54 (2H, d, J=8 Hz), 7.70 (2H, d, J=8.4 Hz), 8.18 (1H, s), 10.11 (1H, bs); [M+1] 366.2 (C17H14F3N3O3 requires 365.31).
