2-Aminopyridine → 5-(3-(2-chloropyrimidin-4-yl)imidazo[1,2-a]pyridin-2-yl)-N-(2,6-difluorophenyl)-2-methoxybenzamide

Participants

Reaction Conditions

Reaction Steps

A tautomeric mixture of 5-[(2-Chloro-4-pyrimidinyl)acetyl]-N-(2,6-difluorophenyl)-2-(methyloxy)benzamide and 5-[(E)-2-(2-chloro-4-pyrimidinyl)-1-hydroxyethenyl]-N-(2,6-difluorophenyl)-2-(methyloxy)benzamide (1.26 g, 3.02 mmol) was dissolved in 60 mL of DCM with stirring. NBS (0.538 g, 3.02 mmol) was added in a single portion. The reaction was stirred for 20 minutes and concentrated in vacuo. The residue was dissolved in 60 mL of dioxane with stirring, and 2-aminopyridine (0.853 g, 9.06 mmol) was added in a single portion. The reaction was heated at 60° C. with an oil bath for 24 hours and cooled to rt. The reaction was stirred at rt for an additional 40 hours. The reaction was poured into half-saturated NaHCO3 solution and EtOAc, and the layers were separated. The organic layer was washed with brine, and the combined aqueous layers were extracted twice with EtOAc. The combined organic layers were dried over MgSO4, filtered, and concentrated in vacuo. The crude product was purified by flash chromatography. Impure fractions were concentrated and further purified by flash chromatography. The combined clean fractions (by TLC) from both runs were combined and concentrated in vacuo to afford 1.07 g (72%) of the desired product. 1H NMR (400 MHz, DMSO-d6): δ 9.80 (s, 1H), 9.40 (d, J=7.0 Hz, 1H), 8.57 (d, J=5.1 Hz, 1H), 8.10 (d, J=1.5 Hz, 1H), 7.84-7.77 (m, 2H), 7.57 (m, 1H), 7.39 (m, 1H), 7.33-7.26 (m, 2H), 7.24-7.14 (m, 3H), 3.99 (s, 3H).

Provenance & Evidence