Fuming sulfuric acid → HCID 178527626, compound

Participants

Reaction Steps

4,5,6-trichloro-2-trifluoromethylbenzimidazole (145 parts) was added gradually to stirred oleum (1260 parts) and the mixture then refluxed for 2 hours. After cooling, the mixture was poured into water (3000 parts), the temperature being allowed to rise to near boiling. The mixture was cooled to room temperature overnight and the crystalline product was filtered off, washed with water and dried to give 165.9 parts (92% yield) of 5,6,7-trichloro-2-trifluoromethylbenzimidazole-4-sulphonic acid.

Provenance & Evidence