Etude dans la série des radicaux hétérocycliques: partie XIV. Radicaux diméthyl‐3, 4‐isoxazolyl‐5. Réactivité en série aromatique et hétéroaromatique: nouvelle voie d'accès à des diméthyl‐3, 4‐isoxazoles subsitués en C(5) par des groupements aryle et hétéroaryle

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Abstract
The aprotic decomposition of 5‐amino‐3, 4‐dimethyl‐isoxazole with excess isoamyl nitrite in aromatic solvents (alkylbenzenes, polyalkylbenzenes, anisole etc.) and in heteroaromatic solvents (thiophene, 2, 4‐dimethylthiazole, pyridine, 4‐alkylpyridines, dimethyl‐ and trimethyl‐pyridines) leads to 5‐aryl‐ and 5‐heteroaryl‐isoxazoles in yields of about 40%. This method provides a new way of obtaining 5‐iodo‐3, 4‐dimethyl‐isoxazole by the aprotic decomposition of the corresponding amine in the presence of iodine (yield: 30%).The relative reactivity of the 3,4‐dimethylisoxazol‐5‐yl radical in alkyl benzenes, in anisole and in alkylpyridines is very similar to that of other heteroaromatic radicals with the radical site next to a sulfur or an oxygen atom. The radical shows electrophilic character because of the inductive effect of the oxygen atom. In the pyridine series an abnormally high percentage of 2‐substitution occurs. This may be explained by a solvatation effect. The characteristic GLC., NMR. and MS. data are reported for most of the compounds studied.