N-bromobutanimide → 4-Bromo-1-(1,1-dimethylethyl)-1H-pyrazole

HRID 473338Notes

Reaction equation

HRID 473338 reaction equation
[C:1]([N:5]1[CH:9]=[CH:8][CH:7]=[N:6]1)([CH3:4])([CH3:3])[CH3:2].C1C(=O)N([Br:17])C(=O)C1.S(=O)(O)[O-].[Na+]>ClCCl>[Br:17][C:8]1[CH:7]=[N:6][N:5]([C:1]([CH3:4])([CH3:3])[CH3:2])[CH:9]=1

Participants

5

Reactant 3

HCID 67184N-bromobutanimideHCID 134698151-tert-Butyl-1H-pyrazole2×HCID 23665763Sodium Bisulfite

Product 1

HCID 532168984-Bromo-1-(1,1-dimethylethyl)-1H-pyrazoleYield 93.4%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To an ice cooled solution (0° C. to 10° C.) of 1-(tert-butyl)pyrazole (1.75 kg, 14.09 mol) in dichloromethane (12.9 kg) was added NBS (2.63 kg, 14.79 mol) portionwise. The solution was stirred at 0° C. until the content of 1-(tert-butyl)pyrazole<30% (GC), then warmed to RT and stirred until the sample taken shows <1.0% by GC. On receipt of a pass result, 10% sodium bisulfite aqueous was added to the reaction mixture until KI-starch did not turn to blue. The organic phase was then washed with 5% NaCl solution and brine in sequence, then evaporated to give the title compound as a brown liquid (2.67 kg, 93.4% yield; GC purity 99.1% a/a).

Workup

  1. customOn receipt of a pass result
  2. washThe organic phase was then washed with 5% NaCl solution and brine in sequence
  3. customevaporated

Sources & evidence

ORD record
ord-4075a5e729c5443db50c083ef0390bbf
Source dataset
uspto-grants-2014_01
Patent number
US08633319B2

Reaction notes

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