Crystallization method for intermediates of carbapenem antibiotics

Abstract

An improved crystallization method for an azetidinone compound represented by the formula 1: , which is extremely useful as a common intermediate for the synthesis of 1β-methylcarbapenem compounds. The present method provides crystals having higher quality and stability than conventional crystals and excellent filterability at the time of recovery; and an azetidinone compound having a low content of impurity, and which has a controlled particle size distribution of crystals and improved handleability and stability. The crystallization is carried out by adding a hydrocarbon solvent to a solution in which an azetidinone compound extremely useful as a common intermediate for the synthesis of 1β-methylcarbapenem compounds is dissolved in the presence of a seed crystal in an amount of 200% by weight or less based on the weight of the azetidinone compound.

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