Cyanogen Bromide → 1-Isobutyl-2-amino-6-bromobenzimidazole

HRID 250736Notes

Reaction equation

HRID 250736 reaction equation
O.O.[Sn](Cl)Cl.[CH2:6]([NH:10][C:11]1[CH:16]=[C:15]([Br:17])[CH:14]=[CH:13][C:12]=1[N+:18]([O-])=O)[CH:7]([CH3:9])[CH3:8].C(=O)(O)[O-].[Na+].[N:26]#[C:27]Br>O.C(O)C.C(OCC)(=O)C>[CH2:6]([N:10]1[C:11]2[CH:16]=[C:15]([Br:17])[CH:14]=[CH:13][C:12]=2[N:18]=[C:27]1[NH2:26])[CH:7]([CH3:9])[CH3:8]

Participants

8

Reactant 4

HCID 10476Cyanogen BromideHCID 61436Stannous chloride dihydrateHCID 516892Sodium BicarbonateHCID 589488465-bromo-N-isobutyl-2-nitroaniline

Product 1

HCID 653467761-Isobutyl-2-amino-6-bromobenzimidazoleYield 86.4%

Reagents, catalysts & solvents 3

HCID 702EthanolSolventHCID 962WaterSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
70 °C

Procedure

Add tin(II) chloride dihydrate (245.5 g, 1.09 mol) to a solution of N-[isobutyl]2-nitro-5-bromoaniline (49.5 g, 0.180 mol) in 2:1 ethyl acetate:ethanol (900 mL). Stir at 70° C. for 2 hours. Pour the reaction mixture into a slurry of ice in water and treat with saturated aqueous sodium bicarbonate. Add ethyl acetate (250 mL) and wash the organic phase sequentially with water (2×600 mL) and saturated aqueous sodium chloride (2×600 mL). Dry over magnesium sulfate and concentrate under reduced pressure. Dissolve the residue in ethanol (600 mL). Add cyanogen bromide (32.6 g, 0.31 mol) and stir at room temperature for 15 hours. Add saturated aqueous sodium carbonate (500 mL) and extract with ethyl acetate (600 mL). Wash the organic phase sequentially with water (2×400 mL) and saturated aqueous sodium chloride (2×400 mL). Dry over magnesium sulfate and concentrate under reduced pressure. Suspend the residue in diethyl ether (300 mL), stir for 15 minutes, filter, and dried under reduced pressure to provide the desired compound as a light brown solid (41.7 g, 86% yield).

Workup

  1. washAdd ethyl acetate (250 mL) and wash the organic phase sequentially with water (2×600 mL) and saturated aqueous sodium chloride (2×600 mL)
  2. dry with materialDry over magnesium sulfate
  3. concentrationconcentrate under reduced pressure
  4. dissolutionDissolve the residue in ethanol (600 mL)
  5. extractionAdd saturated aqueous sodium carbonate (500 mL) and extract with ethyl acetate (600 mL)
  6. washWash the organic phase sequentially with water (2×400 mL) and saturated aqueous sodium chloride (2×400 mL)
  7. dry with materialDry over magnesium sulfate
  8. concentrationconcentrate under reduced pressure
  9. stirringstir for 15 minutes
  10. filtrationfilter
  11. customdried under reduced pressure

Sources & evidence

ORD record
ord-d448478c37744534ad73612ff08497de
Source dataset
uspto-grants-2011_01
Patent number
US07863310B2

Reaction notes

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