A mixture of [3-({5-chloro-3-[(4-chloro-3-trifluoromethyl-benzene sulfonyl)-methoxymethyl-amino]-pyridin-2-yl}-hydroxy-methyl)-pyridin-2-yl]-carbamic acid tert-butyl ester (750 mg, 1.18 mmol) and MnO2 (512.6 mg, 5.9 mmol) in THF (10 mL) was stirred at 50° C. for overnight. The reaction mixture was cooled to room temperature, filtered through sintered funnel, washed with THF (2×10 mL), dried (anhydrous Na2SO4) and concentrated. The obtained residue was column purified (SiO2, 50% EtOAc-hexanes) to afford (3-{5-chloro-3-[(4-chloro-3-trifluoromethyl-benzenesulfonyl)-methoxymethyl-amino]-pyridine-2-carbonyl}-pyridin-2-yl)-carbamic acid tert-butyl ester (456 mg) 61% in yield. ESMS m/z (relative intensity): 635 (M+H)+ (100).
