Hydrogen Bromide → 3-Bromo-1-(4-fluorophenyl)-5-[4-(methylthio)phenyl]pyrazole

HRID 654803Notes

Reaction equation

N([O-])=O.[Na+].[F:5][C:6]1[CH:11]=[CH:10][C:9]([N:12]2[C:16]([C:17]3[CH:22]=[CH:21][C:20]([S:23][CH3:24])=[CH:19][CH:18]=3)=[CH:15][C:14](N)=[N:13]2)=[CH:8][CH:7]=1.S(=O)(=O)(O)O.[Br-:31].[Na+].Br>O.C(#N)C>[Br:31][C:14]1[CH:15]=[C:16]([C:17]2[CH:22]=[CH:21][C:20]([S:23][CH3:24])=[CH:19][CH:18]=2)[N:12]([C:9]2[CH:10]=[CH:11][C:6]([F:5])=[CH:7][CH:8]=2)[N:13]=1

Participants

Conditions

Temperature: 0 °C

Procedure

A solution of sodium nitrite (0.26 g) in water (0.3 ml) was added to an ice-salt cooled mixture of 1-(4-fluorophenyl)-5-[4-(methylthio)phenyl]-3-pyrazolamine (1 g), acetonitrile (1 ml), sulfuric acid (0.6 ml) and water (1.6 ml). The mixture was stirred at 0° C. for 30 minutes. The resulting mixture was added portionwise to a mixture of cuprous bromide (645 mg), sodium bromide (582 mg), hydrobromic acid (1.7 ml) and water (3 ml) at 80° C. The mixture was stirred at 80° C. for 30 minutes and extracted with toluene. The extract was washed with water, dried, and evaporated in vacuo. The obtained residue was purified by column chromatography on silica gel (10 g) to give crystals of 3-bromo-1-(4-fluorophenyl)-5-[4-(methylthio)phenyl]pyrazole (0.35 g).

Workup

temperaturecooled
stirringThe mixture was stirred at 80° C. for 30 minutes
extractionextracted with toluene
washThe extract was washed with water
customdried
customevaporated in vacuo
customThe obtained residue was purified by column chromatography on silica gel (10 g)

Sources & evidence

ORD record: ord-1f43d160377141a1a4d09d4d0dd9aca5
Source dataset: uspto-grants-1992_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05134142

Reaction notes

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