1-Aryl-3,3-dialkyltriazenes:a convenient synthesis from dry arenediazonium o-benzenedisulfonimides, a high yield breakdown to the strating dry salts and efficient conversions to aryl iodides, bromides and chlorides.

This research comprises three parts. The first part regards the synthesis of 1-aryl-3,3-dialkyltriazenes by reaction of dry arenediazonium o-benzenedisulfonimides, also coming from weakly basic aromatic amines with dimethylamine or diethylamine in aqueous solution at 0-5 °C. Yields were usually greater than 90% and there was the possibility of recovering the o-benzenedisulfonimide, which could be reused to prepare the salts. In the second part it was demonstrated that there is the possibility of reconverting the triazenes into the starting stable dry salts. The reactions were carried out in glacial acetic acid at 50-55 °C and normally afforded salts in yields of around 90-99%. The third part concerns the setting up of two procedures for the conversion of triazenes to aryl iodides, bromides and chlorides. Procedure A used the corresponding aqueous hydrogen halides in acetonitrile at r.t. or 60 °C, sometimes in the presence of aqueous HBF4, sometimes Cu powder (25 examples, yields 65%-88%). Procedure B usually used anhydrous methanesulfonic acid and tetraalkylammonium halides in anhydrous acetonitrile at temperatures varying from r.t. to 80 °C, sometimes in the presence of Cu (16 examples, yields 65-88%).