N-bromobutanimide → Methyl 6-((4-bromophenyl)amino)-7-fluoro-1H-benzo[d]imidazole-5-carboxylate

Participants

Reaction Steps

7-Fluoro-6-phenylamino-3H-benzoimidazole-5-carboxylic acid methyl ester 27a (4.99 g, 17.51 mmol) is dissolved in N,N-dimethylformamide (275 mL). N-bromosuccinimide (3.15 g, 17.70 mmol) is added as a solid and the reaction mixture is stirred at room temperature under N2. After 30 minutes, the reaction mixture is quenched by the addition of aqueous saturated sodium bisulfite solution. The reaction mixture is then poured into a reparatory funnel, diluted with water and ethyl acetate and the layers separated. The aqueous layer is extracted with ethyl acetate. The combined organic extracts are washed three times with water, once with brine and then are dried (Na2SO4) and concentrated under reduced pressure to yield 6.38 g (100%) of the pure desired product as a tan solid. MS ESI (+) m/z 364, 366 (M+Br pattern) detected.

Provenance & Evidence