It is employed as a biochemical for proteomics research. It is also used in the preparation of: acyl-2-aminobenzimidazole analogs and 6-chloro-2-methyl-3-{1-[(3-nitrophenyl)sulfonyl]-1H-pyrazol-3-yl}imidazo[1,2-a]pyridine.
Nitrobenzene is added to excess chlorosulfonic acid, and the temperature is raised gradually to 100 ℃ and held there for 6 h. After cooling, the mixture is poured into ice and water, and 3-nitrobenzenesulfonyl chloride is filtered off in 75 % yield for use as a paste, after being washed (to remove acid) with cold water.
