Triethylborane → 4-[5-(4-fluorophenyl)-2-trifluoromethyl-1-(2-trimethylsilylethoxymethyl)-1H-imidazol-4-yl]benzenesulfonamide

Participants

Reaction Conditions

Reaction Steps

To a solution of the protected sulfone imidazole from step 1 (1.1 g, 2.0 mmol) in THF (15 ml) at 0° C. under an argon atmosphere, n-butyl magnesium bromide (n-BuMgBr) (2M solution in THF, 4.5 ml) was added and the temperature warmed to 25° C. over 30 minutes. Triethylborane (Et3B) (1M solution in THF, 9 ml) was added and the reaction was heated to reflux for 48 hours. The reaction mixture was cooled to 25° C. and a mixture of hydroxylamine-O-sulfonic acid (NH2OSO3H) (2 g) and sodium acetate (2 g) in water (8 ml) was added and rapidly stirred at 25° C. for 16 hours. Water (50 ml) was added and the product was extracted with ethyl acetate, dried (Na2SO4), and evaporated. The residue was purified by chromatography on silica gel using mixtures of ethyl acetate and toluene as the eluent to give 500 mg (45%) of the desired protected sulfonamide. The product was used directly in the next step.

Provenance & Evidence