- 1-Aryl-3,3-dialkyltriazenes: A convenient synthesis from dry arenediazonium o-benzenedisulfonimides - A high yield break down to the starting dry salts and efficient conversions to aryl iodides, bromides and chlorides
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This research comprises three parts. The first part regards the synthesis of 1-aryl-3,3-dialkyltriazenes 3 by reaction of dry arenediazonium o-benzenedisulfonimides 1, 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 (5), which could be reused to prepare the salts 1. In the second part it was demonstrated that there is the possibility of reconverting the triazenes 3 into the starting stable dry salts 1 by using 5 as acid. The reactions were carried out in glacial acetic acid at 50-55 °C and normally afforded salts 1 in yields of around 90-99%. The third part concerns the setting up of two procedures for the conversion of 3 to aryl iodides 9, bromides 10 and chlorides 11. 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%).
- Barbero,Degani,Diulgheroff,Dughera,Fochi
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p. 2180 - 2190
(2007/10/03)
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