Phosphorus oxychloride → 2-Chlorobenzimidazole

HRID 1030503Notes

Reaction equation

HRID 1030503 reaction equation
O[C:2]1[NH:3][C:4]2[CH:10]=[CH:9][CH:8]=[CH:7][C:5]=2[N:6]=1.P(Cl)(Cl)([Cl:13])=O>>[Cl:13][C:2]1[NH:3][C:4]2[CH:10]=[CH:9][CH:8]=[CH:7][C:5]=2[N:6]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178517141HCID 178517141, compound

Product 1

HCID 785722-Chlorobenzimidazole

Procedure

A mixture of 2-hydroxybenzimidazole (300 g, 2.42 mol) and phosphorus oxychloride (1000 g) was heated at reflux temperature for 1 h to obtain a solution. Gaseous HCl was bubbled into the refluxing solution for 4 h and the solution then concentrated on a rotary evaporator. The residue was added to a mixture of aqueous potassium carbonate and methylene chloride and stirred for 18 h. The resulting mixture consisted of 2 liquid layers and a solid. The solid was collected and recrystallized from ethyl acetate and methanol.

Workup

  1. temperaturewas heated
  2. temperatureat reflux temperature for 1 h
  3. customto obtain a solution
  4. customGaseous HCl was bubbled into the refluxing solution for 4 h
  5. concentrationthe solution then concentrated on a rotary evaporator
  6. additionThe residue was added to a mixture of aqueous potassium carbonate and methylene chloride
  7. customThe solid was collected
  8. customrecrystallized from ethyl acetate and methanol

Sources & evidence

ORD record
ord-d535b86a1aa7441e9e303655f57513dd
Source dataset
uspto-grants-1992_04
Patent number
US05106857

Reaction notes

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