5-Aminobenzimidazole → HCID 178507337, compound

HRID 1936584Notes

Reaction equation

HRID 1936584 reaction equation
[NH2:1][C:2]1[CH:10]=[CH:9][C:5]2[N:6]=[CH:7][NH:8][C:4]=2[CH:3]=1.C([O-])(=O)C.[Na+].[Br:16]Br>C(O)(=O)C>[NH2:1][C:2]1[CH:10]=[CH:9][C:5]2[N:6]=[CH:7][NH:8][C:4]=2[C:3]=1[Br:16]

Participants

5

Reactant 3

HCID 136235-AminobenzimidazoleHCID 24408BromineHCID 517045Sodium Acetate

Product 1

HCID 178507337HCID 178507337, compound

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

To a solution of 1.08 g of 5-aminobenzimidazole in 20 mL of glacial acetic acid are added 2.68 g of sodium acetate. To this solution is added dropwise 0.4 mL of bromine. The resulting brown precipitate is stirred at room temperature for 2 hours. The reaction mixture is rotary evaporated and the residue is diluted with water and ethyl acetate. The mixture is basified with 1 N sodium hydroxide and decanted. The organic layer is washed with water followed by brine. The aqueous layers are extracted with ethyl acetate; the combined organic layers are dried over magnesium sulfate, filtered and rotary evaporated. The residue is purified by flash column chromatography on silica gel, eluting with 12.5 to 16.5% methanol/methylene chloride followed by recrystallization from hexanes/ethyl acetate to provide 887 mg of 5-amino-4-bromobenzimidazole as a pale brown solid.

Workup

  1. customThe reaction mixture is rotary evaporated
  2. additionthe residue is diluted with water and ethyl acetate
  3. customdecanted
  4. washThe organic layer is washed with water
  5. extractionThe aqueous layers are extracted with ethyl acetate
  6. dry with materialthe combined organic layers are dried over magnesium sulfate
  7. filtrationfiltered
  8. customThe residue is purified by flash column chromatography on silica gel
  9. washeluting with 12.5 to 16.5% methanol/methylene chloride
  10. customfollowed by recrystallization from hexanes/ethyl acetate

Sources & evidence

ORD record
ord-322ad2c7a534470ea03ee0c5fe81abf3
Source dataset
uspto-grants-2002_05
Patent number
US06391878B2

Reaction notes

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