68189-28-6

Reduction of 2-chloro-6-nitrotoluene-4-sulphonic acid gives 2-amino-6- chlorotoluene-4-sulfonic acid [6387-27-5], which is used as a diazo component.

6-Chloro-2-nitrotoluene is sulfonated with 20 % oleum at 60 ℃ with careful temperature control to avoid a runaway reaction. Work-up is by conventional processes.