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-substituted 4-hydroxy-2(5H)-furanones, including 5-substituted 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 obtained in pure form by evaporation of the mother liquor, followed by the same treatment of the salt as described before.
本发明提供了一种解决技术问题的方法,即通过与对映纯基团分离得到5-取代
4-羟基
呋喃-2-酮的一个或两个对映体。包括5-取代和5,5-二取代,
4-羟基和3,4-二羟基
呋喃酮的混合物被晶化与对映纯碱,例如
金鸡纳碱,分离成纯对映体。在特定的溶剂混合物中,例如95%的
乙醇,一个对映异构体纯盐结晶。然后可以通过过滤和用酸处理盐,例如
三氟乙酸,随后用
水沉淀,过滤和干燥来获得对映纯
呋喃酮。此外,通过蒸发母液,然后用与之前相同的方法处理盐,同样可以获得另一个对映体的纯形式。