Hydrogen Bromide → 2-Bromobenzimidazole

HRID 495263Notes

Reaction equation

HRID 495263 reaction equation
[BrH:1].S[C:3]1[NH:4][C:5]2[CH:11]=[CH:10][CH:9]=[CH:8][C:6]=2[N:7]=1.BrBr>CO>[Br:1][C:3]1[NH:4][C:5]2[CH:11]=[CH:10][CH:9]=[CH:8][C:6]=2[N:7]=1

Participants

5

Reactant 3

HCID 260Hydrogen BromideHCID 24408BromineHCID 178527775HCID 178527775, compound

Product 1

HCID 27762812-Bromobenzimidazole

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a flask were added 24 ml 48% hydrobromic acid and 120 ml methanol. The mixture was cooled to 5 C and 10 g 2-mercaptobenzimidazole was added. Maintaining a temperature of less than 10 C, 41.5 g of bromine were added in small portions. The mixture was allowed to warm to 22 C, and stirred for 16 hours under nitrogen. After cooling to 5 C, the solid was filtered and then added to 50 ml methanol containing 20 ml aqueous ammonium hydroxide. The pH was adjusted to 6.5 with acetic acid, and the mixture was cooled to 5 C. The product was filtered and washed with water, and dried. A second crop was obtained by cooling the filtrates which was filtered, washed with water and dried. The combined crops resulted in 9.05 g of a solid.

Workup

  1. additionwas added
  2. additionwere added in small portions
  3. temperatureto warm to 22 C
  4. temperatureAfter cooling to 5 C
  5. filtrationthe solid was filtered
  6. additionadded to 50 ml methanol containing 20 ml aqueous ammonium hydroxide
  7. temperaturethe mixture was cooled to 5 C
  8. filtrationThe product was filtered
  9. washwashed with water
  10. customdried
  11. customA second crop was obtained
  12. temperatureby cooling the filtrates which
  13. filtrationwas filtered
  14. washwashed with water
  15. customdried

Sources & evidence

ORD record
ord-19d858894678406cac102967629831c0
Source dataset
uspto-grants-2009_05
Patent number
US07538931B2

Reaction notes

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