Cumylamine (1.97 ml), WSC.HCl (2.62 g), and HOBt.H2O (2.10 g) were added to a DMF (60 ml) solution containing 6-(cis-2-(tert-butoxycarbonylamino)cyclohexylamino)-2-chloro-5-fluoronicotinic acid obtained in the 1st step, followed by stirring at room temperature for 4 hours. A saturated aqueous ammonium chloride solution and ethyl acetate were added to the reaction mixture. The organic layer was collected, washed with a saturated aqueous sodium hydrogen carbonate solution and then with saturated saline, and dried over anhydrous magnesium sulfate, and the solvent was distilled away under reduced pressure. Diisopropylether and hexane were added to the obtained residue, solid matter was collected by filtration, and a white solid of tert-butyl cis-2-(6-chloro-3-fluoro-5-(2-phenylpropan-2-ylaminocarbonyl)pyridin-2-ylamino)cyclohexylcarbamate (4.41 g) was thus obtained.
