Liquid purification or separation – Processes – Liquid/liquid solvent or colloidal extraction or diffusing...
Patent
1999-04-26
2000-11-07
Therkorn, Ernest G.
Liquid purification or separation
Processes
Liquid/liquid solvent or colloidal extraction or diffusing...
210656, 2101982, 2105021, B01D 1508
Patent
active
06143180&
DESCRIPTION:
BRIEF SUMMARY
REFERENCE TO RELATED APPLICATIONS
This application is a 371 of PCT/JP98/04696 filed Oct. 16, 1998.
FIELD OF THE INVENTION
The present invention relates to a method for separating optical isomers by liquid chromatography with a separating agent comprising a polysaccharide derivative as the active ingredient.
DESCRIPTION OF THE PRIOR ART
As well known, optical isomers of a compound generally differ in the activities for the living body, though they are chemically the same. Accordingly, it is extremely important in the fields of drugs, agricultural chemicals and biochemistry-related industries to prepare an optically pure compound for the purpose of enhancing drug effects per unit dose and inhibiting side effects and drug-induced sufferings. Preferential crystallization, diastereomeric method, chromatography, enzymatic method, and separative membrane method have been known as means for the separation of isomeric mixtures, i.e., optical resolution. Among them, chromatography is generally widely employed, because efficient optical resolution can be attained by simple and easy operation.
The separating agent to be packed into a column used in chromatographic optical resolution includes optically active polymethacrylate esters, optically active polyacrylamides, optically active crown compounds, optically active amino acid derivatives and polysaccharide derivatives. In particular, a separating agent comprising a polysaccharide derivative is excellent in separating power and general-purpose properties and therefore is used in the optical resolution of many compounds. Several separating agents comprising polysaccharide derivatives respectively are disclosed in U.S. Pat. No. 4,818,394, U.S. Pat. No. 4,861,872, U.S. Pat. No. 4,912,205, U.S. Pat. No. 5,202,433, and so on.
The optical resolution with such a separating agent is conducted mainly under so-called normal-phase conditions wherein an organic solvent such as hexane/2-propanol mixture is used as the mobile phase. However, it is difficult to elute a highly polar compound under normal-phase conditions, while many highly polar compounds are used as drugs. Thus, optical resolution only by normal-phase chromatography is not satisfactory for all compounds. Under these circumstances, methods of optical resolution by reversed-phase chromatography have also been developed. For example, described are mixtures of water with ethanol in U.S. Pat. No. 4,818,394, mixtures of water-soluble organic solvents with acids in JP-A-5-346,423, mixtures of water-soluble organic solvents and buffers in JP-A-5-215,736, mixtures of water-soluble with water in U.S. Pat. No. 5,734,043 and mixtures of water-soluble organic solvents with water or buffers containing various salts in JP-A-3-27,326 as the mobile phase to be used in the reversed-phase chromatography. However, these mobile phases are neutral or acidic, and many compounds could not be optically resolved by the use of such a neutral or acidic mobile phase.
Accordingly, the problem that the present invention is to solve is to provide a method for separating optical isomers which permits optical resolution of compounds which could not sufficiently be optically resolved by the reversed-phase chromatographic methods of the prior art.
SUMMARY OF THE INVENTION
The inventors of the present invention have intensively studied and have found that the above problem can be solved by using a basic mobile phase under reversed-phase conditions. Namely, the present invention relates to a method for separating optical isomers by liquid chromatography with a separating agent comprising a polysaccharide derivative as the active ingredient, wherein the chromatographic separation is conducted under reversed-phase conditions by using a basic mobile phase.
In other words, the present invention is a method for separating optical isomers by liquid chromatography filled with a separating agent comprising a polysaccharide derivative as the active component in the reverse phase condition using a basic mobile phase.
The term "reversed-phase conditions"
REFERENCES:
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patent: 4861872 (1989-08-01), Okamoto et al.
patent: 4912205 (1990-03-01), Okamoto et al.
patent: 5202433 (1993-04-01), Okamoto et al.
patent: 5271833 (1993-12-01), Funkenbusch
patent: 5734043 (1998-03-01), Murakami et al.
PTO Translation of Japan Patent No. 9-194399, Translation No. 2000-1531 Feb. 2000 pp. 1-22.
Daicel Chemical Industries Ltd.
Therkorn Ernest G.
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