Cyclohexane → 5-bromo-N,N-dimethyl-3-(trifluoromethyl)-1H-pyrazole-1-sulfonamide

Participants

Reaction Steps

A stirred solution of N,N-dimethyl-3-(trifluoromethyl)-1H-pyrazole-1-sulfonamide (i.e. the product of Example 10, Step A) (4.25 g, 17.5 mmol) in tetrahydrofuran (50 mL) was cooled to −78° C., and then 2 M n-butyllithium in cyclohexane (10.0 mL, 20.0 mmol) was added dropwise. The reaction mixture was stirred a further 30 minutes, and then bromine (1.0 mL, 3.1 g, 18.7 mmol) was added dropwise. The reaction mixture was stirred for 10 minutes, warmed to room temperature, and quenched with brine (50 mL). The resulting mixture was extracted with diethyl ether, and the extract was dried (MgSO4), and concentrated under reduced pressure to give 6.77 g of title compound as a light yellow oil. This compound was of sufficient purity to use in subsequent reactions.

Provenance & Evidence