Ethanol → 2,3-Difluoro-N-[4-(2-trifluoromethyl-imidazo[1,2-a]pyridin-3-yl)-phenyl]-benzamide

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Reaction Steps

To a solution of 690 mg (2.3 mmol) of 3-(4-Nitro-phenyl)-2-trifluoromethyl-imidazo[1,2-a]pyridine (n) in 30 mL of a 1:1 mixture of CH2Cl2 and ethanol (EtOH) was added 4.3 g (23 mmol) of SnCl2 and 4 drops of H2O. The reaction was allowed to stir overnight at which time it was concentrated in vacuo, and the resulting oil dissolved in 40 mL of EtOAc and washed 3 times with 50 mL of 2N NaOH. The organic layer was then dried over MgSO4 filtered and concentrated in vacuo. 73 mg (0.26 mmol) of the resulting solid was dissolved in 4 mL of CH2Cl2 to which 0.035 mL (0.27 mmol) of 3,4 difluorobenzoylchloride and 0.09 mL (0.52 mmol) diisopropyl ethyl amine (DIPEA) were added. The reaction was allowed to stir for 4 hrs at which time it was diluted with 20 mL CH2Cl2, quenched with 15 mL saturated aqueous NaHCO3 and washed with 15 mL brine. The organic layer was then dried over MgSO4 filtered and concentrated in vacuo. The crude oil was purified by silica gel chromatography 1:3 (EtOAc:Hexanes) to yield 91 mg (84%) of 2,3-Difluoro-N-[4-(2-trifluoromethyl-imidazo[1,2-a]pyridin-3-yl)-phenyl]-benzamide (Compound 70) as a white solid.

Provenance & Evidence