3-(2,4-Dihydroxyphenyl)-4-(4-methoxyphenyl)-5-methyl-1H-pyrazole → 3-(5-Bromo-2,4-dihydroxyphenyl)-4-(4-methoxyphenyl)-5-methyl-1H-pyrazole

Participants

Reaction Steps

Benzyltrimethylammonium tribromide (4.0 g, 10.2 mmol) was added portion-wise to a suspension of 4-[4-(4-methoxy-phenyl)-5-methyl-1H-pyrazol-3-yl]-benzene-1,3-diol (2.95 g, 10 mmol) in dichloromethane (50 ml) and the mixture stirred for ˜90 mins. The mixture washed with water (3×50 ml) and saturated aqueous sodium chloride solution (25 ml). The solution was dried over anhydrous magnesium sulphate and concentrated to give a pale yellow solid. Crude product was purified by column chromatography, on silica, eluting with ethyl acetate/hexane (1:2) to give 4-bromo-6-[4-(4-methoxy-phenyl)-5-methyl-1H-pyrazol-3-yl]-benzene-1,3-diol (1.75 g)

Provenance & Evidence