Sodium hydride (95% dry, 253 mg, 10.00 mmol) was added to a stirred solution of 2,2,2-tirluoroethanol (1.00 g, 10.00 mmol) in THF (15 mL) at 0° C. under nitrogen atmosphere. After stirring for 15 minutes at room temperature, the temperature was lowered to −80° C. using an ethanol-dry ice bath. Trifluoromethanesulfonyl chloride (1.69 g, 10.00 mmol) dissolved in THF (5 mL) was then added in small portions, and the mixture was then left to reach room temperature over night. The reaction mixture was centrifuged and the white precipitate was separated. The solvent was diluted with THF to 25 mL (assumed concentration: 0.4 M). The prepared 2,2,2-trifluoroethyl trifluoromethanesulfonate solution (7.5 mL, 0.4 M) was added to a mixture of EXAMPLE 181A (500 mg, 1.5 mmol) and sodium hydride (95% dry, 94 mg, 3.73 mmol) in THF (10 mL) at 0° C. under nitrogen atmosphere. After stirring at 0° C. for 1.5 h an additional amount of sodium hydride (95% dry, 76 mg, 3.00 mmol) and 2,2,2-trifluoroethyl trifluoromethanesulfonate solution (7.5 mL) was added. After 1 h at 0° C. was die mixture poured on to ice and neutralized with 2.0 M HCl and extracted with DCM. Evaporation of the organic solvent gave a residue which was purified by flash chromatography on silica gel eluting with a 2-5% acetone gradient in DCM. This gave 174 mg (28%) of a white solid: MS (Ionspray, [M+H]+) m/z 414. Anal. Calcd. (found) for C14H14ClF3N2O3S2: C, 40.5 (40.5)%; H, 3.4 (3.4)%; N, 6.7 (6.7)%.
