Efficient Preparation of D-Aspartic Acid β-Methyl Ester as an Aspoxicillin Material by Optical Resolution, Epimerization, and Asymmetric Transformation

概要

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A practical preparation of D-aspartic acid β-methyl ester [D-Asp(OMe)], a raw material for the antibiotic aspoxicillin, has been developed by the use of a second-order asymmetric transformation. The diastereomeric resolution of DL-Asp(OMe) with (-)-1-phenylethanesulfonic acid (PES) resulted in salt formation of less soluble D-・(-) and more soluble L-・(-) in acetonitrile. The soluble L-・(-) was easily epimerized into DL-・(-) by heating it in acetonitrile in the presence of catalysts. Attempted fractional crystallization of DL-・(-) or L-・(-) under such epimerizing conditions led to the desired D-・(-) in 90% yield via equilibrium asymmetric transformation in a solid-liquid heterogeneous system. Details of optimum techniques for the asymmetric transformation are presented.From these results, unique preparation processes of both D-Asp(OMe) and D-p-hydroxyphenylglycine, important intermediate materials for aspoxicillin, have been achieved by asymmetric transformation using chiral PES as the resolving agent.
社団法人日本薬学会の論文
1989-04-25