Sodium Sulfite → 2-bromo-1-(1-methyl-1H-pyrazol-4-yl)ethan-1-one

HRID 1498016Notes

Reaction equation

HRID 1498016 reaction equation
[CH3:1][N:2]1[CH:6]=[C:5]([C:7](=[O:9])[CH3:8])[CH:4]=[N:3]1.[Br-:10].[Br-].[Br-].[NH+]1C=CC=CC=1.[NH+]1C=CC=CC=1.[NH+]1C=CC=CC=1.S([O-])([O-])=O.[Na+].[Na+]>ClCCl.C(O)C.O>[Br:10][CH2:8][C:7]([C:5]1[CH:4]=[N:3][N:2]([CH3:1])[CH:6]=1)=[O:9]

Participants

7

Reactant 3

HCID 24437Sodium SulfiteHCID 35969391-(1-methyl-1H-pyrazol-4-yl)ethan-1-oneHCID 21124087Pyridiniumtribromide

Product 1

HCID 431441522-bromo-1-(1-methyl-1H-pyrazol-4-yl)ethan-1-one

Reagents, catalysts & solvents 3

HCID 702EthanolSolventHCID 962WaterSolventHCID 6344DichloromethaneSolvent2×

Procedure

A solution of 1-(1-methyl-1H-pyrazol-4-yl)ethanone (28.5 g, 230 mmol) in dichloromethane (400 mL) was diluted with absolute ethanol (100 mL) and treated portion-wise with pyridinium tribromide (95%, 77.3 g, 230 mmol). The reaction was stirred at room temperature for 3 hours, during which time it solidified; the mixture was diluted with dichloromethane (300 mL) and water (400 mL), treated with sodium sulfite (5 g) and stirred for 10 minutes. The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was washed with water (200 mL), collected by filtration, washed again with water, and dried to afford the product as an off-white solid. Yield: 41.6 g, 205 mmol, 89%. 1H NMR (500 MHz, CDCl3) δ 7.97-7.98 (m, 1H), 7.95 (br s, 1H), 4.17 (s, 2H), 3.95-3.96 (m, 3H).

Workup

  1. stirringstirred for 10 minutes
  2. dry with materialThe organic layer was dried over magnesium sulfate
  3. filtrationfiltered
  4. concentrationconcentrated in vacuo
  5. washThe residue was washed with water (200 mL)
  6. filtrationcollected by filtration
  7. washwashed again with water
  8. customdried

Sources & evidence

ORD record
ord-ab5ebd51107f4f7e81e4f693321566fd
Source dataset
uspto-grants-2015_12
Patent number
US09200000B2

Reaction notes

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