To a solution of 2-{(2-methoxyethyl)[(trans-2-methylcyclopropyl)methyl]amino}-6-[methyl(methylsulfonyl)amino]isonicotinic acid (14.05 g, 37.8 mmol) in DCM (150 mL) was added diisopropylethyl amine (7.91 mL, 45.4 mmol), Boc-hydrazine (6 g, 45.4 mmol), HOAt (1.03 g, 7.6 mmol) and EDC (8.7 g, 45.4 mmol), and the reaction mixture was stirred at rt for 16 h. The reaction mixture was diluted with EtOAc, washed with 10% KHSO4, aq NaHCO3 and brine, dried over sodium sulfate, concentrated in vacuo, and purified by flash chromatography (silica, 30% to 70% EtOAc in hexane) to give tert-butyl 2-{2-{(2-methoxyethyl)[(trans-2-methylcyclopropyl)methyl]amino}-6-[methyl(methylsulfonyl)amino]isonicotinoyl}hydrazinecarboxylate. MS M+1=486.
