Ammonium Chloride → 5-(8-Bromooctyl)-2-(tert-butyldimethylsilyl)-1-(N,N-dimethylsulfamoyl)imidazole

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Reaction Steps

A solution of 2-(tert-butyldimethylsilyl)-1-(N,N-dimethylsulfamoyl) imidazole (Example 29 step a) (2.62 g, 9.05 mmol) in dry tetrahydrofuran (30 ml) was cooled under an atmosphere of argon to -78° C. n-Butyl lithium (1.5M in hexanes) (7.25 ml, 10.9 mmol) was added over 15 min and the solution stirred for a further 30 min. A solution of 1,8-dibromooctane (2.55 ml 13.6 mmol) in dry tetrahydrofuran (5 ml) was added over 10 min. The solution was stirred for 2 h, allowed to warm to room temperature and stirred for 18 h. Saturated ammonium chloride solution (30 ml) and diethyl ether (30 ml) were added and the ethereal extract was washed with brine and dried over sodium sulfate. Filtration, evaporation of the filtrate and purification by flash column chromatography (silica; 20%; ethyl acetate/hexane) to afford the product (Rf 0.43) as a white solid (2.36 g, 54%).

Provenance & Evidence