Benzyl Bromide → 1-Benzyl-6-chloro-5-iodo-2-methanesulfonyl-1H-benzoimidazole

Participants

Reaction Steps

To a solution of 6-chloro-5-iodo-2-methanesulfonyl-1H-benzoimidazole (12.1 g, 34 mmol) in DMF (100 ml) at 0° C. was added NaH (60% dispersion in mineral oil, 1.5 g, 38 mmol). After 10 minutes, the mixture was warmed to rt and stirred for 45 minutes. Benzyl bromide (6.4 g, 38 mmol) was then slowly added and the reaction was stirred overnight at rt. The volatiles were then removed by rotary evaporation and the residue was partitioned between EtOAc and half-saturated ammonium chloride solution. The resulting emulsion was filtered through celite to obtain a cleaner partition. The EtOAc layer was washed with H2O, brine, and dried with MgSO4. After rotary evaporation, the oily residue was stirred in diethyl ether overnight. The mixture was filtered and the beige solid thus obtained was dried under vacuum at rt for 24 hours to yield the title compound. The filtrate was evaporated to an oil and purified by flash chromatography (SiO2, 220 g). A second crop of the title compound was eluted from the column with 40% EtOAc in hexane.

Provenance & Evidence