反应详情

A mixture of 2′-methanesulfonyl-biphenyl-3,4-diamine (8.09 g, 0.0308 mol) and 2-bromoacetimidic acid ethyl ester hydrochloride salt (11.82 g, 0.0370 mol) in anhydrous ethanol (200 proof, 120 mL) was stirred at room temperature for 12 h. The reaction mixture was concentrated under reduced pressure and extracted with ethyl acetate and brine. The organic layer was dried over Na2SO4, filtered, and the filtrate was concentrated in vacuo to provide 2-bromomethyl-5-(2-methanesulfonyl-phenyl)-1H-benzoimidazole (10.36 g, 92%) as a yellow oil. To a solution of this material in CH2Cl2, was added Boc2O (7.39 g, 0.0339 mol), Et3N (12.9 mL, 0.0924 mol), and DMAP (0.19 g, 0.00154 mol). After stirring 1 h at room temperature, the reaction mixture was concentrated under reduced pressure and the residue was purified by chromatography (silica, EtOAc: hexanes, 1:2) to afford the title compound as a yellow oil (10.17 g, 77%).

1. concentrationThe reaction mixture was concentrated under reduced pressure
2. extractionextracted with ethyl acetate and brine
3. dry with materialThe organic layer was dried over Na2SO4
4. filtrationfiltered
5. concentrationthe filtrate was concentrated in vacuo