A suspension of N-[5-bromo-4-methyl-3-(3-trifluoromethyl-phenyl)-pyridin-2-yl]-N′-hydroxy-2-(4-methanesulfonyl-phenyl)-acetamidine (Int. 12, 165 mg, 0.304 mmol) in toluene (6 mL) and pyridine (98 μL, 1.218 mmol) was cooled to 0° C. and p-toluenesulfonyl chloride (232 mg, 1.218 mmol) was added. The reaction mixture was stirred at 0° C. for 25 mins then at RT for 6 days. Sodium hydrogen carbonate (saturated solution, 30 mL) was added and the mixture was extracted with DCM (2×30 mL). The organic phase was concentrated and the resultant residue purified by flash chromatography eluting with a gradient of 0-100% EtOAc in cyclohexane to give the title compound as a yellow solid (164 mg).
