Benzyl Bromide → 1-benzyl-3-nitro-1H-pyrazole

HRID 546020

Reaction equation

HRID 546020 reaction equation
[N+:1]([C:4]1[CH:8]=[CH:7][NH:6][N:5]=1)([O-:3])=[O:2].[H-].[Na+].[CH2:11](Br)[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1>CN(C)C=O>[CH2:11]([N:6]1[CH:7]=[CH:8][C:4]([N+:1]([O-:3])=[O:2])=[N:5]1)[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1

Participants

5

Reactant 3

HCID 7498Benzyl BromideHCID 24758Sodium hydrideHCID 178526745HCID 178526745, compound

Product 1

HCID 9736491-benzyl-3-nitro-1H-pyrazoleYield 84.2%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of 3-nitro-1H-pyrazole (prepared in example 3, 200 mg, 1.77 mmol) in anhydrous N,N-dimethylformamide (2 mL), a 60% dispersion of sodium hydride in mineral oil (92 mg, 2.30 mmol) was added while stirring under nitrogen. After the effervescence ceased and the mixture was stirred for additional 10 min, benzylbromide (273 μL, 2.33 mmol) was added. The mixture was continued to stir under nitrogen for an additional 2 h. The solvent was removed in vacuo and purification by ISCO flash column chromatography (Teledyne Isco RediSep Flash Column 40 g; 2% methanol/methylene chloride to 5% methanol/methylene chloride) afforded 1-benzyl-3-nitro-1H-pyrazole (303 mg, 84%) as a white solid: H1-NMR (400 MHz, CDCl3) δ: 5.33 (2H, s), 6.84 (1H, d, J=2.7 Hz), 7.26 (2H, m), 7.32 (3H, m), 7.40 (1H, d, J=1.5 Hz).

Workup

  1. stirringthe mixture was stirred for additional 10 min
  2. stirringto stir under nitrogen for an additional 2 h
  3. customThe solvent was removed in vacuo and purification by ISCO flash column chromatography (Teledyne Isco RediSep Flash Column 40 g; 2% methanol/methylene chloride to 5% methanol/methylene chloride)

Sources & evidence

ORD record
ord-4386fe748a4843d1b23c1514536c0660
Source dataset
uspto-grants-2011_05
Patent number
US07935699B2

Linked notes

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