2,4-Difluorophenylhydrazine hydrochloride → 5-(3-bromo-4-fluoro-phenyl)-1-(2,4-difluoro-phenyl)-3-pentafluoroethyl-4,5-dihydro-1H-pyrazole

HRID 2207882Notes

Reaction equation

[Br:1][C:2]1[CH:3]=[C:4]([CH:9]=[CH:10][C:11](=O)[C:12]([F:18])([F:17])[C:13]([F:16])([F:15])[F:14])[CH:5]=[CH:6][C:7]=1[F:8].Cl.[F:21][C:22]1[CH:27]=[C:26]([F:28])[CH:25]=[CH:24][C:23]=1[NH:29][NH2:30]>C(O)(=O)C>[Br:1][C:2]1[CH:3]=[C:4]([CH:9]2[N:29]([C:23]3[CH:24]=[CH:25][C:26]([F:28])=[CH:27][C:22]=3[F:21])[N:30]=[C:11]([C:12]([F:18])([F:17])[C:13]([F:16])([F:15])[F:14])[CH2:10]2)[CH:5]=[CH:6][C:7]=1[F:8]

Participants

Conditions

Temperature: 125 °C

Procedure

1-(3-Bromo-4-fluoro-phenyl)-4,4,5,5,5-pentafluoro-pent-1-en-3-one (2.5 g, 7.1 mmol) prepared in Step 4 and 2,4-difluorophenylhydrazine hydrochloride (1.4 g, 7.8 mmol) were added to acetic acid (35.0 mL). The reaction mixture was stirred at 125° C. for 2 hours, concentrated under reduced pressure, and then ethyl acetate was added thereto. The mixture was washed with a saturated solution of sodium hydrogen carbonate, dried on anhydrous magnesium sulfate, and then concentrated under reduced pressure to give a yellow liquid residue. The resulting residue was purified by silica gel column chromatography (eluent: ethyl acetate/n-hexane=1/30) to give 2.1 g of the titled compound as a yellow liquid.

Workup

concentrationconcentrated under reduced pressure
additionethyl acetate was added
washThe mixture was washed with a saturated solution of sodium hydrogen carbonate
dry with materialdried on anhydrous magnesium sulfate
concentrationconcentrated under reduced pressure
customto give a yellow liquid residue
customThe resulting residue was purified by silica gel column chromatography (eluent: ethyl acetate/n-hexane=1/30)

Sources & evidence

ORD record: ord-5c6fa24679be4214b91c461a0705066a
Source dataset: uspto-grants-2016_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09376420B2

Reaction notes

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