Hydrogen Bromide → HCID 22909691, compound

Participants

Reaction Steps

A solution of sodium nitrite (492 mg) in water (0.6 ml) was added dropwise to a mixture of 1-(4-methoxyphenyl)-5-[4-(methylthio)phenyl]pyrazol-3-amine (2 g) and sulfuric acid (1.2 ml) in water (3 ml) and acetonitrile (6 ml) at 5° C., and the mixture was stirred at the same temperature for 1 hour. The mixture was added portionwise to a mixture of cuprous bromide (1.25 g), sodium bromide (1.2 g) and hydrobromic acid (3.3 ml) in water (6 ml) at 70° to 80° C. during a period of 15 minutes, and the resulting mixture was stirred at 80° C. for 30 minutes. The aqueous layer was removed by decantation and the oily residue was extracted with toluene. The extract was washed with water, dried, and concentrated in vacuo. The residue (1.1 g) was purified by column chromatography on silica gel (20 g) eluting with a mixture of chloroform and n-hexane (2:1) to give crystals of 3-bromo-1-(4-methoxyphenyl)-5-[4-(methylthio)phenyl]pyrazole (0.62 g).

Provenance & Evidence