Unusual reactions of aryl diazonium sulphonates possessing ortho-t-amino-substituents

Abstract

Aryl diazonium sulphonates with an ortho-t-amino-substituent cyclise on treatment with sulphur dioxide to give triazines and benzimidazolium sulphonates. Hot aqueous sodium hydroxide causes loss of nitrogen from these heterocycles with formation of the corresponding t-amino-aryls and -lactams. A reaction mechanism involving the t-amino-group is postulated.