Sodium Carbonate → 4-bromo-5-(tert-butyl-dimethyl-silanyloxymethyl)-1-methyl-3-(4-trifluoromethyl-phenyl)-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

A solution of 5-(tert-butyl-dimethyl-silanyloxymethyl)-1-methyl-3-(4-trifluoromethyl-phenyl)-1H-pyrazole (162 mg, 437 μmol) in dichloromethane (1.7 ml) was added within 10 min to a mixture of bromine (20 μl, 480 μmol) and sodium carbonate (93 mg, 880 μmol) in dichloromethane (4.3 ml) at 0° C. under an argon atmosphere. After stirring at 0 to 5° C. for 1 h and then at ambient temperature for 1 h, the mixture was quenched with water (5 ml) and extracted two times with dichloromethane. The combined extracts were washed with aqueous saturated NaHSO3 solution and brine/ice water 1/1 and dried over sodium sulfate. Removal of the solvent under reduced pressure left off-white crystals which were purified by column chromatography (silica gel, heptane/AcOEt) to give 90 mg (0.2 mmol, 46%) of the title compound as colorless crystals.

Provenance & Evidence