| 摘要 |
This invention affords a solution tO the technical problem of obtaining one or both enantiomers of 5-substituted 4-hydroxyfuran-2-ones in pure form by resolution with enantiomerically pure bases. Racemic mixtures of 5-substitut ed 4-hydroxy-2(5H)-furanones, including 5-substitited and 5,5-disubstituted, 4- hydroxy and 3,4-dihydroxy furanones are separated into pure enantiomers by crystallization with an enantiomerically pure base, such as cinchonidine. In specific solvent mixtures, for example, 95 % ethanol, the diastereomerically pure salt of one enantiomer crystallizeS. The enantiomerically pure furanone can then be obtained simply by filtration and treatment of the salt with an acid, for example, trifluoracetic acid, followed by precipitation with water , filtration and drying. Moreover, the other enantiomer may be equally obtaine d in pure form by evaporation of the mother liquor, followed by the same treament of the salt as described before.
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