Methyl iodide → Methyl 5-(4-bromo-2-chloroanilino)-4-fluoro-1-methyl-1H-benzimidazole-6-carboxylate

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Reaction Steps

A solution of 6-(4-bromo-2-chloro-phenylamino)-7-fluoro-3H-benzoimidazole-5-carboxylic acid methyl ester 8b (150 mg, 0.38 mmol), iodomethane (28 μL, 0.45 mmol) and potassium carbonate (78 mg, 0.56 mmol) in dimethylformamide (1.5 mL) is stirred at 75° C. for one hour. The reaction mixture is diluted with ethyl acetate, washed with saturated aqueous potassium carbonate (2×), brine, and dried (Na2SO4). Flash column chromatography (20:1 methylene chloride/ethyl acetate) provides 56 mg (36%) of the more mobile 6-(4-bromo-2-chloro-phenylamino)-7-fluoro-3-methyl-3H-benzoimidazole-5-carboxylic acid methyl ester 9a as a white solid. 19F NMR (376 MHz, CD3OD) −133.5 (s). MS APCI (+) m/z 412, 414 (M+, Br pattern) detected. Also isolated is 54 mg (35%) of 6-(4-bromo-2-chloro-phenylamino)-7-fluoro-1-methyl-1H-benzoimidazole-5-carboxylic acid methyl ester as a white solid. 19F NMR (376 MHz, CD3OD) −139.9 (s). MS APCI (+) m/z 412, 414 (M+, Br pattern) detected.

Provenance & Evidence