Potassium Carbonate → 1,3-Dihydro-5-methoxy-2H-benzimidazol-2-one

HRID 1750109Notes

Reaction equation

HRID 1750109 reaction equation
[NH2:1][C:2]1[CH:7]=[C:6]([O:8][CH3:9])[CH:5]=[CH:4][C:3]=1[NH:10][C:11](=[O:17])OC(C)(C)C.C([O-])([O-])=O.[K+].[K+]>CN(C=O)C>[CH3:9][O:8][C:6]1[CH:5]=[CH:4][C:3]2[NH:10][C:11](=[O:17])[NH:1][C:2]=2[CH:7]=1

Participants

4

Reactant 2

HCID 11430Potassium CarbonateHCID 10752410tert-butyl N-(2-amino-4-methoxyphenyl)carbamate

Product 1

HCID 5911011,3-Dihydro-5-methoxy-2H-benzimidazol-2-oneYield 72%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
130 °C

Procedure

Intermediate 36 (7.3 g, 30.6 mmol) was dissolved in DMF (70 mL). To this solution was added anhydrous K2CO3 (4.7 g, 33.7 mmol) and the mixture was heated to reflux (130° C.) for 5 h. The solvent was removed under pressure, the residue was poured into ice water, and the aq phase was extracted with EtOAc. The combined organic layers were dried over anhydrous Na2SO4, concentrated under vacuum, and the resulting yellow solid was recrystallized from EtOH to give 5-methoxy-1H-benzo[d]imidazol-2(3H)-one (intermediate 37) (3.6 g, 72%) as a yellow solid. mp: 249-251° C.

Workup

  1. temperaturethe mixture was heated
  2. customThe solvent was removed under pressure
  3. additionthe residue was poured into ice water
  4. extractionthe aq phase was extracted with EtOAc
  5. dry with materialThe combined organic layers were dried over anhydrous Na2SO4
  6. concentrationconcentrated under vacuum
  7. customthe resulting yellow solid was recrystallized from EtOH

Sources & evidence

ORD record
ord-6d0397958cfe48609787bb7eb1287c18
Source dataset
uspto-grants-2015_10
Patent number
US09156822B2

Reaction notes

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