A solution of triphenylphosphine (279 mg, 1.06 mmol) in methylene chloride (5 mL) was cooled to 0° C. and then treated with N-bromosuccinimide (188.7 mg, 1.06 mmol). The reaction mixture was stirred at 0° C. for 30 min and then treated with a solution of 3-cyclohexyl-2-(4-methanesulfonyl-3-trifluoromethyl-phenyl)-propionic acid (237 mg, 0.626 mmol) in methylene chloride (4 mL). The clear solution was stirred for 15 min at 0° C. and then allowed to warm to 25° C. where it was stirred for 2 h. The reaction mixture was then treated with 2-aminothiazole (188 mg, 1.88 mmol), and the resulting suspension was stirred for 15 h at 25° C. The reaction mixture was concentrated in vacuo to remove methylene chloride, and the residue was diluted with ethyl acetate (50 mL) and a 1N aqueous hydrochloric acid solution (50 mL). The two layers were separated, and the aqueous layer was extracted with ethyl acetate (1×30 mL). The combined organic extracts were successively washed with a saturated aqueous sodium bicarbonate solution (1×50 mL) and a saturated aqueous sodium chloride solution (1×50 mL), dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo. Biotage chromatography (FLASH 40S, Silica, 4/1 to 2/1 hexanes/ethyl acetate) afforded 3-cyclohexyl-2-(4-methanesulfonyl-3-trifluoromethyl-phenyl)-N-thiazol-2-yl-propionamide (83 mg, 29%) as an amorphous solid: EI-HRMS m/e calcd for C20H23F3N2O3S2 (M+) 460.1102, found 460.1100.
