Potassium Carbonate → 6-(4-Bromo-2-chloro-phenylamino)-7-fluoro-3-(2-methanesulfonyl-ethyl)-3H-benzoimidazole-5-carboxylic acid methyl ester

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Reaction Steps

6-(4-Bromo-2-chloro-phenylamino)-7-fluoro-3H-benzoimidazole-5-carboxylic acid methyl ester 8b (1.55 g, 3.89 mmol) is dissolved in 15 mL DMF under N2. K2CO3 (0.70 g, 5.06 mmol) is added followed by methyl vinyl sulfone (0.41 mL, 4.67 mmol). After stirring 16 hours at room temperature, the reaction mixture is diluted with ethyl acetate and water. The layers are separated and the organic layer is washed with water (3×) and brine. The combined aqueous washes are extracted with ethyl acetate. The combined organic extracts are dried (MgSO4) and concentrated under reduced. Purification by dissolving the residue in methylene chloride and precipitating with diethyl ether, repeated several times, provides 1.16 g (59%) pure desired product as a yellow solid: MS APCI (+) m/z 506, 504 (M+ Br pattern) and 400, 398 (M− methyl ethyl sulfone Br pattern).

Provenance & Evidence