Diphenylphosphoryl azide (DPPA) (0.09 mL, 0.423 mmol, 1.1 equiv.) and triethylamine (0.075 mL, 0.54 mmol, 1.4 equiv.) were added to 5-tert-butyl-2-(2-methylpyrimidin-5-yl)-2H-pyrazole-3-carboxylic acid (100 mg, 0.384 mmol, 1.0 equiv.) in 2.0 mL anhydrous dimethoxyethane in a sealed tube. The mixture was heated at 85° C. for 2.5 h, then a solution of the cyclopropylmethylaminopyrimidine-ether intermediate (see Example 4)(118 mg, 0.38 mmol, 1.0 equiv.) in 3.0 mL anhydrous THF was added and the resulting mixture stirred at room temperature overnight. The solvent was removed in vacuo and the crude urea was purified by column chromatography on silica gel using 0–65% EtOAc in hexanes eluent mixtures. The product was purified further by prep-HPLC affording 15 mg of the title compound (7% yield).
