3-[(4-Iodo-2-methylphenyl)amino]isonicotinic acid (example 3) (50 mg, 0.141 mmol) was dissolved in 4 ml dry THF followed by the addition of 1,1″-carbonyldiimidazole (CDI) (0.311 mmol, 50 mg), methanesulfonamide (0.169 mmol, 16.1 mg) and DBU (0.169 mmol, 26 mg). The mixture was stirred for 16 h at 40° C. and the volatiles were removed in vacuo. The crude material was purified by preparative HPLC to give 20.3 mg (47 μmol; 33% yield) of pure desired product. LC-MS (method III): rt=2.74 min; m/z [M+H]+ 432.
