O-Phenylenediamine → 2-(1H-benzo[d]imidazol-2-yl)-5-methylbenzenamine

HRID 921025Notes

Reaction equation

HRID 921025 reaction equation
OOS([O-])=O.[K+].[N+:7]([C:10]1[CH:17]=[C:16]([CH3:18])[CH:15]=[CH:14][C:11]=1[CH:12]=O)([O-])=O.[NH2:19][C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][C:21]=1[NH2:26].C(=O)([O-])[O-].[K+].[K+]>CN(C=O)C.O>[NH2:7][C:10]1[CH:17]=[C:16]([CH3:18])[CH:15]=[CH:14][C:11]=1[C:12]1[NH:19][C:20]2[CH:25]=[CH:24][CH:23]=[CH:22][C:21]=2[N:26]=1

Participants

7

Reactant 4

HCID 7243O-PhenylenediamineHCID 11430Potassium CarbonateHCID 5904464-Methyl-2-nitrobenzaldehydeHCID 23707502Potassium hydroxy sulfite

Product 1

HCID 679955852-(1H-benzo[d]imidazol-2-yl)-5-methylbenzenamine

Reagents, catalysts & solvents 2

HCID 962WaterSolvent2×HCID 6228DimethylformamideSolvent

Conditions

Temperature
20 °C

Procedure

33.8 g (55 mmol) of oxone [70693-62-8] are added in portions to a solution of 13.5 g (100 mmol) of 2-nitro-4-methylbenzaldehyde [20357-22-6] and 11.9 g (110 mmol) of 1,2-diaminobenzene in a mixture of 150 ml of DMF and 5 ml of water with stirring and cooling to 20° C. at such a rate that the temperature does not exceed 35° C. The reaction mixture is subsequently stirred at room temperature until conversion of the aldehyde is complete (about 4 h). The reaction mixture is stirred into a solution of 40 g of potassium carbonate in 2000 ml of water, stirred for a further 15 min., extracted with three 300 ml portions of dichloromethane in each case, the organic phase is washed twice with 300 ml of water, once with 500 ml of sat. sodium chloride solution and dried over sodium sulfate. The dichloromethane solution is filtered through silica gel, and the dichloromethane is removed in vacuo. The yellow residue is taken up in 500 ml of methanol, blanketed with nitrogen with stirring, 3 g of 10% Pd/C are added, and the mixture is hydrogenated at room temperature in an autoclave at a hydrogen pressure of 2 bar. When the uptake of hydrogen is complete, the catalyst is filtered off via a Celite bed, and the methanol is removed in vacuo. Yield: 18.5 g (83 mmol), 83%. Purity: >95% according to 1H-NMR.

Workup

  1. customdoes not exceed 35° C
  2. custom(about 4 h)
  3. stirringstirred for a further 15 min.
  4. extractionextracted with three 300 ml portions of dichloromethane in each case
  5. washthe organic phase is washed twice with 300 ml of water, once with 500 ml of sat. sodium chloride solution
  6. dry with materialdried over sodium sulfate
  7. filtrationThe dichloromethane solution is filtered through silica gel
  8. customthe dichloromethane is removed in vacuo
  9. stirringwith stirring
  10. addition3 g of 10% Pd/C are added
  11. customis hydrogenated at room temperature in an autoclave at a hydrogen pressure of 2 bar
  12. filtrationthe catalyst is filtered off via a Celite bed
  13. customthe methanol is removed in vacuo

Sources & evidence

ORD record
ord-5d882c263986494abf37585cba10a6a5
Source dataset
uspto-grants-2016_03
Patent number
US09273080B2

Reaction notes

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