Methyl chloroformate → Methyl 4-(6-(2-(4-(2-methylpyridin-4-yl)phenyl)acetamido)pyridin-3-yl)piperazine-1-carboxylate

To the solution of 2-(4-(2-methylpyridin-4-yl)phenyl)-N-(5-(piperazin-1-yl)pyridin-2-yl)acetamide 131-1 (20 mg, 0.05 mmol) in THF (1 mL) was added DIEA (19 mg, 0.15 mmol) and methyl chloroformate (5.2 mg, 0.055 mmol). The reaction was stirred at room temperature for 40 min. The solvent was removed by rotary evaporation and the residue was purified by reverse phase HPLC to give N-(5-(4-acetylpiperazin-1-yl)pyridin-2-yl)-2-(4-(2-methylpyridin-4-yl)phenyl)acetamide 132 as off-white solid. MS m/z 446.2 (M+1); 1H NMR 400 MHz (DMSO-d6) δ10.55 (s, 1H), 8.72 (d, 1H), 8.18 (s, 1H), 8.08 (m, 1H), 7.96 (d, 1H), 7.90 (d, 2H), 7.84 (d, 1H), 7.50 (d, 2H), 7.35 (dd, 1H), 3.72 (s, 2H), 3.54 (s, 3H), 3.43 (t, 4H), 3.03 (t, 3H), 2.65 (s, 3H).