Benzoyl Peroxide → tert-Butyl 3-(bromomethyl)-1H-pyrazole-1-carboxylate

HRID 1825252Notes

Reaction equation

HRID 1825252 reaction equation
[C:1]([O:5][C:6]([N:8]1[CH:12]=[CH:11][C:10]([CH3:13])=[N:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[Br:14]N1C(=O)CCC1=O.C(OOC(=O)C1C=CC=CC=1)(=O)C1C=CC=CC=1>C(Cl)(Cl)(Cl)Cl.C(OCC)(=O)C.C([O-])(O)=O.[Na+]>[C:1]([O:5][C:6]([N:8]1[CH:12]=[CH:11][C:10]([CH2:13][Br:14])=[N:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2]

Participants

7

Reactant 3

HCID 7187Benzoyl PeroxideHCID 67184N-bromobutanimideHCID 21035385tert-Butyl 3-methyl-1H-pyrazole-1-carboxylate

Product 1

HCID 23573257tert-Butyl 3-(bromomethyl)-1H-pyrazole-1-carboxylateYield 51.3%

Reagents, catalysts & solvents 3

HCID 5943Carbon TetrachlorideSolventHCID 8857Ethyl AcetateSolventHCID 516892Sodium BicarbonateSolvent

Procedure

3-methyl pyrazole 1-carboxylic acid tert-butyl ester (4.0 g, 21.95 mmol) was dissolved in 73 mL of CCl4. N-bromosuccinimide (5.47 g, 30.73 mmol) and benzoyl peroxide (744 mg, 3.07 mmol) were added. This solution was warmed to reflux for 5.5 hours and then cooled to room temperature. The reaction mixture was diluted with ethyl acetate and saturated NaHCO3 solution. The phases were separated, and the organic phase was extracted with brine, dried over Na2SO4, filtered and concentrated to give a yellow oil. Purification by column chromatography (SiO2, ISCO chromatography system, elution with 5 to 10% ethyl acetate in hexanes) provided 3-bromomethyl pyrazole 1-carboxylic acid tert-butyl ester (53-2) as a pale yellow oil (2.94 g, 51% yield). 1H NMR was consistent with desired product.

Workup

  1. temperatureThis solution was warmed
  2. temperatureto reflux for 5.5 hours
  3. customThe phases were separated
  4. extractionthe organic phase was extracted with brine
  5. dry with materialdried over Na2SO4
  6. filtrationfiltered
  7. concentrationconcentrated
  8. customto give a yellow oil
  9. customPurification
  10. washby column chromatography (SiO2, ISCO chromatography system, elution with 5 to 10% ethyl acetate in hexanes)

Sources & evidence

ORD record
ord-2615b58493d3496d8efb05e24e75a39c
Source dataset
uspto-grants-2006_05
Patent number
US07045532B2

Reaction notes

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