2-Butene, 1-bromo-3-methyl- → [1-(3-methyl-but-2-enyl)-1H-benzoimidazol-2-yl]-methanol

HRID 250962Notes

Reaction equation

HRID 250962 reaction equation
[NH:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[C:2]1[CH2:10][OH:11].Br[CH2:13][CH:14]=[C:15]([CH3:17])[CH3:16].CCN(C(C)C)C(C)C>CN(C=O)C>[CH3:16][C:15]([CH3:17])=[CH:14][CH2:13][N:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[C:2]1[CH2:10][OH:11]

Participants

5

Reactant 3

HCID 700922-Butene, 1-bromo-3-methyl-HCID 785692-(Hydroxymethyl)-1H-benzimidazoleHCID 81531Diisopropylethylamine

Product 1

HCID 67272334[1-(3-methyl-but-2-enyl)-1H-benzoimidazol-2-yl]-methanolYield 36.1%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of (1H-benzoimidazol-2-yl)-methanol (457 mg, 3.09 mmol) and 4-bromo-2-methyl-2-butene (0.36 mL, 3.09 mmol) in DMF (10 mL) was added DIPEA (0.69 mL, 3.70 mmol) at 60° C. overnight and in the morning, the mixture was cooled and concentrated. The residue was dissolved in saturated NaHCO3 (20 mL) and extracted with CH2Cl2 (3×30 mL). The combined organic layers were dried (MgSO4), filtered, and concentrated to afford a brown oil. Purification by flash column chromatography on silica gel using 2% MeOH/CH2Cl2 afforded [1-(3-methyl-but-2-enyl)-1H-benzoimidazol-2-yl]-methanol as a pale yellow solid (241 mg, 36%). 1H NMR (CDCl3) δ 1.72 (s, 3H), 1.87 (s, 3H), 4.80 (d, 2H, J=6.6 Hz), 4.86 (s, 2H), 5.21 (td, 1H, J=6.0, 1.2 Hz), 7.19-7.23 (m, 3H), 7.65-7.68 (m, 1H).

Workup

  1. temperaturein the morning, the mixture was cooled
  2. concentrationconcentrated
  3. dissolutionThe residue was dissolved in saturated NaHCO3 (20 mL)
  4. extractionextracted with CH2Cl2 (3×30 mL)
  5. dry with materialThe combined organic layers were dried (MgSO4)
  6. filtrationfiltered
  7. concentrationconcentrated
  8. customto afford a brown oil
  9. customPurification by flash column chromatography on silica gel using 2% MeOH/CH2Cl2

Sources & evidence

ORD record
ord-ba538d4ddbec4421a3b6973f8a328c61
Source dataset
uspto-grants-2011_01
Patent number
US07863293B2

Reaction notes

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