Benzoic Acid → 2-Phenylbenzimidazole-5-sulfonic acid

HRID 1006199Notes

Reaction equation

HRID 1006199 reaction equation
[S:1](=[O:5])(=O)([OH:3])[OH:2].[NH2:6][C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=1[NH2:13].[C:14](O)(=O)[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1>>[C:15]1([C:14]2[NH:6][C:7]3[CH:12]=[C:11]([S:1]([OH:3])(=[O:5])=[O:2])[CH:10]=[CH:9][C:8]=3[N:13]=2)[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1

Participants

4

Reactant 3

HCID 243Benzoic AcidHCID 1118Sulfuric Acid2×HCID 7243O-Phenylenediamine

Product 1

HCID 339192-Phenylbenzimidazole-5-sulfonic acidYield 49%

Conditions

Temperature
200 °C

Procedure

Without intermediate isolation which (apart from starting materials and secondary products) can, as in this case, still comprise large amounts of sulphuric acid, it is not always possible to further process crude reaction solutions. This often leads to the formation of contaminated products and/or to poor yields in the subsequent stage. This is described in the example in EP-A 4 203 072, wherein a mixture of 1,2-diaminobenzene, benzoic acid and 96% strength sulphuric acid is mixed and heated to 200° C. In the subject process, 2-phenylbenzimidazole-5-sulphonic acid is obtained as the secondary product in a yield of 49% of theory. The product is isolated in a yield of 60%, with the process carried out in 86% strength sulphuric acid at 178°.

Workup

  1. customreaction solutions
  2. customto poor yields in the subsequent stage
  3. additionis mixed

Sources & evidence

ORD record
ord-6bcffdb18749453e9424115e44a9f50a
Source dataset
uspto-grants-2004_09
Patent number
US06787666B2

Reaction notes

Loading…