A mixture of 2-(4-{[5-chloro-2-{[1,5-dimethyl-1H-pyrazol-3-yl)carbonyl]amino}-4-(trifluoromethyl)phenyl]amino}phenyl)ethyl (4-methylphenyl)sulfonylcarbamate (step 3, 145 mg, 0.223 mmol) in 2N NaOH (1 ml) and ethanol (2 ml) was stirred at 50° C. for 85 h. After cooling, the pH value was adjusted to 4.0 by addition of 2N HCl. The mixture was diluted with water (80 ml), and extracted with dichloromethane (80 ml×3). The combined organic layer was washed with brine (50 ml), dried (MgSO4), and concentrated. Purification by PTLC eluting with hexane/ethyl acetate (1:3) to afford 30 mg (21%) of the title compound as a red solid.
