摘要 |
A process for preparing an optically active trans-3-substituted glycidic acid ester compound of the formula (I): <CHEM> wherein ring A is a substituted or unsubstituted benzene ring, and R<1> is an ester residue, which comprises: preparing a solution of one optical isomer (A) and the other optical isomer (B) of the ester compound (I), both of which are the optical isomers due to the asymmetric carbons at 2- and 3-positions, and an ester compound (B') which is different from the isomer (B) only in the ester residue R<1>, crystallizing the optical isomer (A) from the solution up to the extent that the optical isomer (A) is crystallized without the precipitation of the optical isomer (B) due to the presence of the ester compound (B') though the optical isomer (B) would precipitate if the ester compound (B') were not present, and isolating the crystals of the optical isomer (A), whereby a desired optical isomer (A) can be obtained in high purity and in a high yield such that the desired isomer can be crystallized until the concentration of the desired isomer in the mother liquor becomes very low as compared with conventional processes. |