Etude en série triazénique. IV. Synthèse et réactivité d'aryl‐3‐(diméthyl‐3,4‐isoxazolyl‐5)‐1‐triazènes et d'arylazo‐4‐diméthyl‐3,4‐isoxazolones‐5

Synthesis and reactivity of 3‐aryl‐1‐(3,4‐dimethyl‐5‐isoxazolyl)‐triazenes and 4‐arylazo‐3,4‐dimethylisoxazol‐5‐ones According to the experimental conditions and the nature of the substituents on the aromatic ring, aryldiazonium salts react with 5‐amino‐3,4‐dimethylisoxazole (3) leading to either 3‐aryl‐1 (3,4‐dimethyl‐5‐isoxazolyl)‐triazenes (1A) or 4‐arylazo‐3,4‐dimethylisoxazol‐5‐ones (4). Analyses of the products resulting from thermal decomposition of these triazenes in aromatic substrates and in DMSO and their behaviour in acidic medium show that it is essentially the arylazo form 1B which is reactive.