The invention relates to a new process for the industrial preparation of 4-chloro-3-sulfamoyl-N-(2,3-dihydro-2-methyl-1H-indol-1-yl)benzamide from monochloramine and 2,3-dihydro-2-methyl-1H-indole.
Disclosed is a method of preparing N-amino compounds from corresponding secondary amines by reacting a secondary amine with nitrous acid and zinc in a neutral pH reaction media to form the corresponding N-amine.