Azobisisobutyronitrile → 4-Bromomethyl-1-(2-chloro-phenyl)-5-(4-chloro-phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester

HRID 1294840

Reaction equation

HRID 1294840 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[C:10]([CH3:11])=[C:9]([C:12]2[CH:17]=[CH:16][C:15]([Cl:18])=[CH:14][CH:13]=2)[N:8]([C:19]2[CH:24]=[CH:23][CH:22]=[CH:21][C:20]=2[Cl:25])[N:7]=1)=[O:5])[CH3:2].[Br:26]N1C(=O)CCC1=O.CC(N=NC(C#N)(C)C)(C#N)C>C(Cl)(Cl)(Cl)Cl>[CH2:1]([O:3][C:4]([C:6]1[C:10]([CH2:11][Br:26])=[C:9]([C:12]2[CH:17]=[CH:16][C:15]([Cl:18])=[CH:14][CH:13]=2)[N:8]([C:19]2[CH:24]=[CH:23][CH:22]=[CH:21][C:20]=2[Cl:25])[N:7]=1)=[O:5])[CH3:2]

Participants

5

Reactant 3

HCID 6547AzobisisobutyronitrileHCID 67184N-bromobutanimideHCID 58760952Ethyl 1-(2-chlorophenyl)-5-(4-chlorophenyl)-4-methyl-1h-pyrazole-3-carboxylate

Product 1

HCID 587609464-Bromomethyl-1-(2-chloro-phenyl)-5-(4-chloro-phenyl)-1H-pyrazole-3-carboxylic acid ethyl esterYield 64%

Reagents, catalysts & solvents 1

HCID 5943Carbon TetrachlorideSolvent

Procedure

A mixture of 1-(2-chloro-phenyl)-5-(4-chloro-phenyl)-4-methyl-1H-pyrazole-3-carboxylic acid ethyl ester I-4a (2.8 g, 7.46 mmol), N-bromosuccinimide (1.6 g, 8.95 mmol), AIBN (245 mg, 1.49 mmol) in CCl4 (60 ml) was heated under reflux for 17 hours. The reaction was cooled to room temperature, filtered to remove any solids, and concentrated under vacuum. The crude residue was purified via silica gel chromatorgraphy (Flash 40) using a solvent gradient of 10% EtOAc/hexanes to 20% EtOAc/hexanes to give the desired product (I-4b) as an amorphous solid (2.2 g, 64%): +APCI MS (M+1) 455.0.

Workup

  1. temperatureunder reflux for 17 hours
  2. filtrationfiltered
  3. customto remove any solids
  4. concentrationconcentrated under vacuum
  5. customThe crude residue was purified via silica gel chromatorgraphy (Flash 40)

Sources & evidence

ORD record
ord-855fbb13045b45dd9952a942241ecefb
Source dataset
uspto-grants-2007_07
Patent number
US07241788B2

Linked notes

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