N,N-Diethylaniline → 3-Bromo-2-(4-chloro-2-fluorophenyl)-2,4,5,6-tetrahydrocyclopenta[c]pyrazole

HRID 1763211Notes

Reaction equation

HRID 1763211 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([N:8]2[C:12](=O)[C:11]3[CH2:14][CH2:15][CH2:16][C:10]=3[NH:9]2)=[C:4]([F:17])[CH:3]=1.P(Br)(Br)([Br:20])=O.C(N(CC)C1C=CC=CC=1)C.[OH-].[Na+]>O.CN(C)C=O>[Br:20][C:12]1[N:8]([C:5]2[CH:6]=[CH:7][C:2]([Cl:1])=[CH:3][C:4]=2[F:17])[N:9]=[C:10]2[CH2:16][CH2:15][CH2:14][C:11]=12

Participants

7

Reactant 4

HCID 7061N,N-DiethylanilineHCID 14798Sodium HydroxideHCID 24613Phosphorus oxybromideHCID 227622242-(4-chloro-2-fluorophenyl)-1,4,5,6-tetrahydrocyclopentapyrazol-3(2H)-one

Product 1

HCID 203091013-Bromo-2-(4-chloro-2-fluorophenyl)-2,4,5,6-tetrahydrocyclopenta[c]pyrazole

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6228DimethylformamideSolvent

Procedure

A mixture of 6.3 parts of 2-(4-chloro-2-fluorophenyl)-1,4,5,6-tetrahydrocyclopentapyrazol-3(2H)-one, 7.9 parts of phosphorous oxybromide, 3.7 parts of N,N-diethylaniline and 10 parts of N,N-dimethylformamide was refluxed 24 hours and poured into 100 parts of water. After neutralizing with 50% aqueous sodium hydroxide solution, the mixture was extracted twice with 100 parts of diethyl ether. The ether extract was dried over anhydrous magnesium sulfate and the solvent was removed under a reduced pressure of 100 mm. Hg at ambient temperature. The crude product was recrystallized from ethanol-water to yield 2.1 parts of 3-bromo-2-(4-chloro-2-fluorophenyl)-2,4,5,6-tetrahydrocyclopentapyrazole melting at 106°-110°.

Workup

  1. temperaturewas refluxed 24 hours
  2. extractionthe mixture was extracted twice with 100 parts of diethyl ether
  3. extractionThe ether extract
  4. dry with materialwas dried over anhydrous magnesium sulfate
  5. customthe solvent was removed under a reduced pressure of 100 mm. Hg at ambient temperature
  6. customThe crude product was recrystallized from ethanol-water

Sources & evidence

ORD record
ord-81191662caa842c8bfe1d3273643f4ac
Source dataset
uspto-grants-1978_09
Patent number
US04111681

Reaction notes

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