2-Nitrobenzaldehyde → HCID 178423936, compound

HRID 843235Notes

Reaction equation

HRID 843235 reaction equation
[NH2:1][C:2]1[C:7]([NH2:8])=[CH:6][CH:5]=[CH:4][C:3]=1[CH3:9].[N+:10]([C:13]1[CH:20]=[CH:19][CH:18]=[CH:17][C:14]=1[CH:15]=O)([O-:12])=[O:11]>CO.O.C(O)(=O)C.CO.O.CCO.Cl.CC([O-])=O.CC([O-])=O.[Cu+2].O>[CH3:9][C:3]1[C:2]2[NH:1][C:15]([C:14]3[CH:17]=[CH:18][CH:19]=[CH:20][C:13]=3[N+:10]([O-:12])=[O:11])=[N:8][C:7]=2[CH:6]=[CH:5][CH:4]=1

Participants

10

Reactant 2

HCID 111012-NitrobenzaldehydeHCID 175932,3-Diaminotoluene

Product 1

HCID 178423936HCID 178423936, compoundYield 72%

Reagents, catalysts & solvents 7

HCID 165397Cupric acetate monohydrateCatalystHCID 176Acetic AcidSolventHCID 313Hydrochloric AcidSolventHCID 702EthanolSolventHCID 887MethanolSolventHCID 962WaterSolvent3×HCID 22242641Methanol--water (1/1)Solvent

Procedure

2,3-Diaminotoluene (12.2 g, 0.1 mol) was dissolved in the mixture of MeOH/H2O (500 mL, v/v=1:1), acetic acid (10 mL) was added to the stirring mixture. 2-Nitrobenzaldehyde (21.1 g, 0.14 mol) in MeOH (250 mL) and Cu(OAc)2.H2O (28.0 g, 0.14 mmol) in water (250 mL) were added subsequentially to the mixture. It was then heated to reflux for 3 h under vigously stirring, a pale yellow precipitate was formed. Filtered while it was hot and washed with water to afford a gray-yellow solid. Redissolved the precipitate in EtOH (600 mL) and HCl (75 ML, Conc.), a solution of Na2S.9 H2O (48.0 g, 0.2 mol) in water (300 mL) were added. The mixture was heated to reflux for 1 h resulted in a black slurry. Cooled down to room temperature, it was filtered through a pad of celite to remove of CuS. The filtrate was neutralized with ammonium hydroxide to PH=8-9. Concentration using a rotary evaporator, a green-yellow precipitate was formed. After filtration and dried in vaccum oven, the crude product was purified by column chromatography on silica gel using a mixture of hexane/ethyl acetate (1:1) as the eluent to give 4-methyl-2-(2-nitrophenyl)-benzimidazole (18 g, 72%) as a yellow needle crystal. Rf=0.21 (hexane/ethyl acetate=1:1); 1H NMR (250 MHz, CDCl3) δ 2.60 (s, 3H), 7.10 (d, J=8.2 Hz, 1H), 7.20 (t, J=7.9 Hz, 1H), 7.41 (bs, 1H), 7.52-7.66(m, 2H), 7.89-7.97 (m, 2H), 10.41 (bs, 1H); HRMS: Calcd for C14H11N3O2 253.0851, found 253.0854.

Workup

  1. additionwas added to the stirring mixture
  2. temperatureIt was then heated
  3. temperatureto reflux for 3 h
  4. customa pale yellow precipitate was formed
  5. filtrationFiltered while it
  6. washwashed with water
  7. customto afford a gray-yellow solid
  8. temperatureThe mixture was heated
  9. temperatureto reflux for 1 h
  10. customresulted in a black slurry
  11. filtrationit was filtered through a pad of celite
  12. customto remove of CuS
  13. concentrationConcentration
  14. customa rotary evaporator
  15. customa green-yellow precipitate was formed
  16. filtrationAfter filtration
  17. customdried in vaccum oven
  18. customthe crude product was purified by column chromatography on silica gel using
  19. additiona mixture of hexane/ethyl acetate (1:1) as the eluent

Sources & evidence

ORD record
ord-83a83065b0d24f2f9565d2f10abc8648
Source dataset
uspto-grants-2002_04
Patent number
US06376664B1

Reaction notes

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