PURPOSE: To obtain the title mixture containing cis-modification useful in the fields of perfume, medicine, chemicals, etc., by heating a trans-2,3-disubstituted cyclopentanone in the presence of a metal carbonate followed by, if needed, distillation.
CONSTITUTION: A mixture containing cis-modification can be obtained by heating of a trans-2,3-disubstituted cyclopentanone at 10-220°C for 5min-36hr in the presence of a metal carbonate ( pref. alkali metal salt). The objective product of higher quality can be obtained by after-treatment such as distillation and/or solvent extraction after completion of the reaction. In the distillation, the amount of the metal carbonate to be used is required to regulate at low level, being at ≤100ppm (on a weight basis) based on the trans-modification during the heating; and thereafter, it is preferable that the distillation be made at ≤150°C in the boiling point and at ≤200°C in the liquid temperature. Thereby, the cis-modification can be obtained in high yield.
FUJISAWA HIROSHI
TANAKA HIDEYUKI
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