A solution of 8-chloro-7-[(2-fluoro-4-iodophenyl)amino]imidazo[1,2-a]pyridine-6-carboxylic acid (78 mg, 0.18 mmol) (prepared using procedures similar to those described in US 2006030610 and US 2005054701), 1,1-dimethylethyl 2-(3-hydroxyazetidin-3-yl)piperidine-1-carboxylate (46.7 mg, 0.18 mmol), 4-(dimethylamino)pyridine (66 mg, 0.55 mmol), and finally 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (42 mg, 0.21 mmol) in dimethylformamide (2 mL) was stirred at room temperature for 15 hours. The reaction mixture was partition between 5% aqueous lithium chloride and ethyl acetate and the aqueous portion was extracted twice using ethyl acetate. The combined organic portion was washed with 1 N HCl, brine, dried over sodium sulfate, filtered and concentrated in vacuo to afford a brown residue which was purified by column chromatography. Eluting with ethyl acetate, the isolated product was concentrated in vacuo to afford 101 mg, 0.15 mmol (83%) of 1,1-dimethylethyl 2-[1-({8-chloro-7-[(2-fluoro-4-iodophenyl)amino]imidazo[1,2-a]pyridin-6-yl}carbonyl)-3-hydroxyazetidin-3-yl]piperidine-1-carboxylate as a white solid. The solid was immediately dissolved in methanol (5 mL) and 4 N HCl in dioxane was added. The solution was briefly heated to reflux and then was concentrated in vacuo. The resultant residue was purified by preparative reverse phase HPLC. Isolated product was concentrated in vacuo to afford 36 mg, 0.06 mmol (40%) of 1-({8-chloro-7-[(2-fluoro-4-iodophenyl)amino]imidazo[1,2-a]pyridin-6-yl}carbonyl)-3-piperidin-2-ylazetidin-3-ol acetate as a white solid. 1H NMR (400 MHz, DMSO): 8.78 (s, 1H), 8.19 (s, 0.5H), 8.15 (s, 0.5H), 8.00 (s, 1H), 7.62 (s, 1H), 7.55 (d, 1H), 7.31 (d, 1H), 6.54-6.49 (m, 1H), 4.24-4.12 (m, 1H), 3.97-3.86 (m, 2H), 3.63-3.56 (m, 1H), 2.98-2.90 (m, 1H), 2.50-2.40 (m, 1H), 1.72-1.61 (m, 1H), 1.56-1.43 (m, 2H), 1.32-1.14 (m, 2H), 1.07-0.94 (m, 1H); MS (EI) for C22H22ClFIN5O2: 570 (MH+).
