Ring Transformation of 1-Substituted 3,5-Dinitro-4-pyridones to 4-Nitro-5(2H)-isoxazolone by Hydroxylamine

Abstract New ring transformations of 3,5-dinitro-1-(4-nitrophenyl)-4-pyridone and its homologues with hydroxylamine were found to give 4-nitro-5(2H)-isoxazolone. These results were rationalized by double ring transformations in sequence. The fact that the 4-position of the 4-pyridone behaved as an electrophlic site was the first example in this series of ring transfomations, and was caused by the alpha-effect of the reagent. Some reactions of the isoxazolone were carried out.