Benzimidazole → 1-(3-Bromo-1-propyl)benzimidazole

HRID 50996Notes

Reaction equation

HRID 50996 reaction equation
[N:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[NH:3][CH:2]=1.[H-].[Na+].[Br:12][CH2:13][CH2:14][CH2:15]Br>CN(C=O)C>[Br:12][CH2:13][CH2:14][CH2:15][N:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[CH:2]1

Participants

5

Reactant 3

HCID 5798BenzimidazoleHCID 80011,3-DibromopropaneHCID 24758Sodium hydride

Product 1

HCID 222523291-(3-Bromo-1-propyl)benzimidazoleYield 74%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of benzimidazol (355 mg, 3.00 mmol) in dry DMF (10 mL) was added NaH (83 mg, 3.3 mmol) at 20° C. under N2 atmosphere. The reaction mixture was stirred for 30 min, and then 1,3-dibromopropane (1.82 g, 9.00 mmol) was added and stirres for additional 15 h at 20° C. The reaction was quenched by addition of H2O, and the product was extracted with EtOAc. The organic solution was then washed with H2O and brine, dried over MgSO4, filtered and concentrated in vacuo. 1-(3-Bromo-1-propyl)benzimidazole (530 mg, 74%) was isolated by flash chromatography on a silica gel column by elution with EtOAc/Hexanes a pale yellow oil. 1H NMR (CDCl3, 300 MHz) δ2.40 (qu, 2H, J=6.6 Hz), 3.33 (t, 2H, J=6.2 Hz), 4.42 (t, 2H, J=6.6 Hz), 7.12-7.20 (m, 1H), 7.27-7.48 (m, 2H), 7.43-7.49 (m, 1H), 7.78-7.86 (m, 1H) ppm.

Workup

  1. waitstirres for additional 15 h at 20° C
  2. customThe reaction was quenched by addition of H2O
  3. extractionthe product was extracted with EtOAc
  4. washThe organic solution was then washed with H2O and brine
  5. dry with materialdried over MgSO4
  6. filtrationfiltered
  7. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-898edd5d828f4588b33757d596d816f7
Source dataset
uspto-grants-2004_03
Patent number
US06713471B1

Reaction notes

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