PRODUCTION OF ALPHA-ISOXAZOLE-SUBSTITUTED METHYL KETONE

摘要

PROBLEM TO BE SOLVED: To obtain anα-isoxazole-substituted methyl ketone in high yield by subjecting isoxazolylisoxazole derivative to reductive decomposition. SOLUTION: A 4-isoxazolylisoxazole derivative of formula I (R<1> is a 1-4C alkyl or a 1-4C haloalkyl) is hydrogenated with hydrogen in acidic conditions in the presence of a metal catalyst such as palladium or nickel (e.g. 2-10% palladium-activated carbon or Raney nickel), at ordinary pressure or under pressure, preferably at -10 deg.C to boiling point of a solvent used to selectively open hydroxyisoxazole ring and then hydrolyzed and decarboxylated to provide the objective compound of formula II (e.g. 5-acetonyl-3-methylisoxazole). The compound of formula II is obtained also by reducing the compound of formula I with a metal or a metal salt (e.g. tin or iron sulfate). The compound of formula II is useful as an intermediate for agrochemicals.