Trans-4-(4-nitro-3-trifluoromethyl-phenylamino)-cyclohexanecarboxylic acid (500 mg, 1.50 mmol, prepared in accordance with Example 42), 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (570 mg, 1.5 mmol), and diisopropylethylamine (600 μL, 3.30 mmol) were dissolved in dry tetrahydrofuran (10 mL). The resulting mixture was stirred at room temperature for 10 min, and then cooled to 0° C. A solution of methylamine in tetrahydrofuran (750 μL, 2M, 1.50 mmol) and dimethylformamide (1 mL) was added, and the resulting mixture was stirred at room temperature for 3 hr. The mixture was then concentrated under vacuum. The resulting residue was taken up in dichloromethane (25 mL), and the organic phase was washed with water (10 mL), and then with aqueous saturated hydrogencarbonate (3×10 mL). The organic layer was collected, dried over magnesium sulfate, filtered, and concentrated under vacuum. The residue was diluted in dioxane (5 mL), and a concentrated solution of HCl in dioxane was added (10 mL, 4N). A precipitate formed, which was then washed with diethylether (10 mL) and dried under vacuum. The desired product was isolated as a yellow solid (498 mg, 87% yield).
