Hydrochloric Acid → 1,3-Bis(4-tert-butylbenzyl)-1,3-dihydrobenzimidazol-2-one

HRID 221960Notes

Reaction equation

HRID 221960 reaction equation
[NH:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[NH:3][C:2]1=O.[C:11]([C:15]1[CH:22]=[CH:21][C:18]([CH2:19]Br)=[CH:17][CH:16]=1)([CH3:14])([CH3:13])[CH3:12].[C:23](=[O:26])([O-])[O-].[K+].[K+].[I-].[K+].Cl>O.CN(C=O)C>[C:11]([C:15]1[CH:22]=[CH:21][C:18]([CH2:19][N:1]2[C:5]3[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=3[N:3]([CH2:2][C:18]3[CH:21]=[CH:22][C:15]([C:11]([CH3:14])([CH3:13])[CH3:12])=[CH:16][CH:17]=3)[C:23]2=[O:26])=[CH:17][CH:16]=1)([CH3:14])([CH3:13])[CH3:12]

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 4875Potassium IodideHCID 11430Potassium CarbonateHCID 119852-Hydroxy benzimidazoleHCID 878361-(Bromomethyl)-4-(1,1-dimethylethyl)benzene

Product 1

HCID 597070731,3-Bis(4-tert-butylbenzyl)-1,3-dihydrobenzimidazol-2-oneYield 43.1%

Reagents, catalysts & solvents 2

HCID 962WaterSolvent2×HCID 6228DimethylformamideSolvent

Conditions

Temperature
75 °C

Procedure

To a solution of benzimidazolinone (1.5 g, 11.2 mmol) in abs. DMF (25 mL) there were added 4-tert-butylbenzyl bromide (1.8 mL, 9.8 mmol), potassium carbonate (2.76 g, 20 mmol), and a catalytic amount of potassium iodide under a blanket of argon. The reaction mixture was heated to 75° C. over a period of 2 h. Following cooling, the reaction mixture was poured into a solution of H2O (200 mL) and 2N hydrochloric acid solution in H2O (10 mL). The resulting mixture was extracted with EtOAc (5×40 mL), the combined organic phases were washed with sat. NaCl solution (2×30 mL), dried over Na2SO4, and the solvent was removed in vacuo. The residue was taken up in chloroform (50 mL), and the resulting solid matter was isolated by filtration. The filtrate was concentrated in vacuo. The residue was purified by means of column chromatography (SiO2, cyclohexane/EtOAc 2:1), and there were obtained 1,3-bis(4-tert-butylbenzyl)-1,3-dihydrobenzimidazol-2-one (O) (0.9 g, mp: 164-168° C.) and the desired product 1-(4-tert-butylbenzyl)-1,3-dihydrobenzimidazol-2-one (N) (615 mg, 22% of theory, mp: 179-180° C.) as the more polar substance.

Workup

  1. temperatureFollowing cooling
  2. extractionThe resulting mixture was extracted with EtOAc (5×40 mL)
  3. washthe combined organic phases were washed with sat. NaCl solution (2×30 mL)
  4. dry with materialdried over Na2SO4
  5. customthe solvent was removed in vacuo
  6. customthe resulting solid matter was isolated by filtration
  7. concentrationThe filtrate was concentrated in vacuo
  8. customThe residue was purified by means of column chromatography (SiO2, cyclohexane/EtOAc 2:1)

Sources & evidence

ORD record
ord-91a1da69cefb424d99386e5e9b57bb1e
Source dataset
uspto-grants-2012_06
Patent number
US08207182B2

Reaction notes

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