Eisai Chemical Co., Ltd.

Katsuhiko Hirota

Masahiko Tsujii

Hirofumi Kuroda

Yoshikazu Furusawa

Disclosed herein is a purification method of a crude product by column chromatography on silica gel or on a vinyl alcohol copolymer. Methanol-containing n-hexane and/or n-hexane-containing methanol is used as an eluent to elute the crude product, thereby obtaining an intended product with high purity and good yield. The solvents recovered from the effluent can be regenerated without any trouble such as rectification and a great cost by mixing them under stirring and then separating the resulting upper and lower layer from each other. The column used can also be reused again and again by washing with methanol. The separation and purification method is excellent in separation efficiency, operation efficiency and economical efficiency.

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Ibaraki Prefecture, Japan

Katsuhiko Hirota