PURPOSE: To readily separate and obtain the subject compounds which are intermediates for medicines and agricultural chemicals by subjecting a mixture containing optically active 4-hydroxyl-2-cyclopentenones and optically active 2-cyclopentenone esters to crystallizing treatment using a specific solvent.
CONSTITUTION: A mixture containing optically active 4-hydroxy-2- cyclopentenones expressed by formula I (R' is H or lower alkyl; n is 4-8; mark *indicates asymmetric carbon atom) and optically active 2-cyclopentenone esters expressed by formula II (R" is lower alkyl) is subjected to crystallizing treatment in a mixed solvent of a water-soluble organic solvent and water at a temperature ≥10°C below the melting point of the esters expressed by formula II which are to be crystallized. Thereby, the compounds expressed by formula II are crystallized and separated to afford the objective compounds expressed by formula I from the residual liquid part. Methanol, acetone, etc., are used as the above-mentioned organic solvent in an amount within the range of 0.5-2 weight ratio based on water. The total amount of the organic solvent and water is preferably 1-10 times based on the raw material mixture.
KAI SEIICHI
UEDA YUJI
| JPS63109797A | 1988-05-14 | |||
| JPS60169451A | 1985-09-02 |
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