EPOXY-AZETIDINONE, ITS PRODUCTION AND ITS USE

PROBLEM TO BE SOLVED: To produce a new epoxy-azetidinone compound useful as an intermediate, etc., for synthesizing 1-oxapenem being an effective inhibitor of β-lactamase by epoxydizing an azetidinone compound. SOLUTION: This new epoxy-azetidinone compound is represented by formula I (R is 3-o-chlorophenyl-5-methyl-isoxazol-4-yl-carbonylamino, phthalimide, phenylacetylamino, etc.; R is a 1-4C alkylaminosulfonyl, benzylaminosulfonylh a 1,4-C alkyloxysulfonyl, arylaminosulfonyl, etc.; R is a benzyloxy, a 1-4C alkyloxy, silyloxy, etc.; R and R are each H, a halogen, a 1-4C alkyloxy, etc.) and useful as an intermediate for synthesizing β-lactamase inhibitor. The compound is produced by subjecting azetidinone compound of formula II to an epoxydizing reaction by using 30% hydrogen peroxide, etc.