Synthetic Reactions Using Isoxazole Compounds

The activation of C-5 methyl group of 3.5-dimethylisoxazoles is discussed by MINDO/Z calculation and H-D exchange reaction.The regioselective substitution reaction of 5-methylisoxazoles with electrophiles such as alkyl halides, carbon dioxide, carbonyl compounds, Schiff bases, nitriles, nitrites and nitroso compounds,is reviewed.Also the conversions of resulting isoxazole derivatives to 0-diketones, enones and some heterocyclic compounds are reviewed.In 1891, Claisen had succeeded to synthesize the isoxazole compound, which was an unsaturated five membered ring compound containing oxygen and nitrogen atoms.1) Since then, many papers have been reported concerning to the isoxazole compounds.2)The spectral data of isoxazoles such as IR, UV and NMR are similar to those of furans, p y r i d i n e s and other azoles.From the microwave absorption spectral analysis, the structure of lsoxazole ring was confirmed to be a planar pentagon showing in Fig.By the study of the heat of oonbustion, the resonance energy of ..