PURPOSE: To inexpensively obtain the title substance useful as a synthetic raw material for carbapenems and penems, by treating a 4-acyl-β-lactam derivative with a monoperphthalic acid in a solvent.
CONSTITUTION: A compound shown by formula I (R is 1-4C alkyl, aryl or aralkyl) is treated with 1-20 equivalent monoperphthalic acid in a solvent (e.g., methylene chloride, ethyl acetate or benzene) at -78-100°C to give a compound shown by formula II. The monoperphthalic acid is obtained as a disodium salt from phthalic anhydride and an aqueous solution of hydrogen peroxide. In the reaction between the compound shown by the formula I and the monoperphthalic acid, the monoperphthalic acid is not isolated, disodium monoperphthalate is acidified to give monoperphthalic, which is extracted with a solvent, dried and used for the reaction.
ITO YOSHIO
TAKASE MITSURU
KOBAYASHI YUKO
NIPPON SODA CO
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