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Separating agent for enantiomeric isomersRelated Patent Categories: Liquid Purification Or Separation, Processes, ChromatographySeparating agent for enantiomeric isomers description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070215549, Separating agent for enantiomeric isomers. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] This is a division of Ser. No. 10/936,846, filed Sep. 9, 2004, which is a division of Ser. No. 10/258 706, filed Oct. 25, 2002, now abandoned, which was the national stage of International Application No. PCT/JP02/02137, filed Mar. 7, 2002, which International Application was not published in English. TECHNICAL FIELD OF THE INVENTION [0002] The present invention relates to a separating agent for enantiomeric isomers, in particular, a separating agent suitably used for separating enantiomeric isomers in chromatography. More particularly, the present invention relates to a separating agent for enantiomeric isomers that can enantiomerically resolve many kinds chiral compounds with high separation factors in the analysis of pharmaceuticals, foods, agricultural chemicals, fragrants and the like. PRIOR ARTS [0003] Many organic compounds have enantiomeric isomers that have the same physical and chemical properties such as boiling point, melting point, solubility and the like but show a difference in the physiological activity that influences the living body of an organism. This difference in the physiological activity between enantiomeric isomers is attributable to the following. In most cases, proteins and carbohydrates that compose the organism are composed only of the one of the enantiomeric isomers so that they show a difference in the manner of action to the other enantiomeric isomer. In the field of pharmaceutical preparations, particularly, in many cases, there are significant differences in medical effect and toxicity between the two enantiomeric isomers. Therefore, in the Guideline for the Production of Pharmaceuticals, the Ministry of Health, Labor and Welfare describes "when the drug of interest is a racemic modification, it is desirable to preliminarily study absorption, distribution, metabolism and excretion kinetics of each enantiomeric isomer." [0004] Since enantiomeric isomers have completely the same physical and chemical properties, they cannot be separated and analyzed by ordinary separation means. Therefore, extensive studies have been made on techniques for easily and precisely separating and analyzing a wide variety of enantiomeric isomers. [0005] As a result, as an analytical technique that meets these requirements, an optical resolution method by high performance liquid chromatography (HPLC), in particular an optical resolution method by using a chiral column for HPLC (chiral stationary phase method) has been developed and widely spread. The chiral column referred to herein means an asymmetry recognition agent itself or a column using, as a filler, a chiral stationary phase composed of an asymmetry recognition agent supported on a suitable carrier. [0006] As such asymmetry recognition agents, for example, optically active poly(triphenylmethylmethacrylate) (c.f., Japanese Patent Application Laid Open No. 57-150432), cellulose and amylose derivatives (Y. Okamoto, M. Kawashima and K. Hatada, J. Am. Chem. Soc., 106, 5337, 1984), ovomucoid, which is a protein (Japanese Patent Application Laid Open No. 63-307829) and the like have been developed. It has been known that among many chiral stationary phases for HPLC, a chiral stationary phase having a cellulose or amylose derivative supported on silica gel has high asymmetry recognition ability to an extremely wide variety of compounds. Furthermore, in recent years, studies on a liquid chromatographic fractionation method for optically active substances in an industrial scale by the combination of the chiral stationary phase for HPLC with a simulated moving bed process have been developed (Pharm Tech Japan, 12, 43 (1996). In order to not only simply perform a base line separation but also further increase productivity of chromatographic fractionation, a chiral stationary phase being capable of further separating a target compound or having as high a value of the separation factor .alpha. as possible has been desired. [0007] Since the HPLC chiral stationary phase is frequently used under a reversed phase condition that is an aqueous mobile phase, frequent replacement between an organic solvent-based mobile phase and the aqueous mobile phase is complicated and unsuitable from the point of the maintenance of analytic equipment. It might also lead to a wrong operation by the mixing of the mobile phases. Therefore, it has been desired to perform an analysis in either one of the mobile phase systems, more preferably, in the aqueous mobile phase system. Further, in relation to the recent environmental problems, there is a trend to reduce the organic solvent discharged as mobile phase as much as possible. [0008] As the chiral stationary phases to be used under a reversed phase condition, one using the protein as an asymmetry recognition agent, one using a polysaccharide derivative capable of separating the widest variety of racemic compounds as an asymmetry recognition agent, and the like have been developed and marketed, and an asymmetry recognition agent having further remarkable separation characteristics has been demanded. [0009] Recently, there is growing interest in a thin-layer chromatography (chiral TLC) for enantiomeric isomer separation capable of performing an enantiomeric isomer separation in capillary electrophoresis (CE) field or performing an enantiomeric isomer separation with a separating operation easier than HPLC. The cellulose and amylose derivative-based chiral stationary phases developed and marketed so far as HPLC chiral stationary phase are mostly formed of aromatic derivatives, except an acetate derivative, because it has been considered that the interaction between .pi.-.pi.electrons plays an important part in the asymmetry recognition between a substituent of a polysaccharide derivative and a solute (Society of Synthetic Organic Chemistry, 54, 344 (1996), Japanese Patent Application Laid Open No. 60-142930). However, an asymmetry recognition agent having a substituent having a large UV absorptive group as an aromatic group had the disadvantage in that it is not applicable to, for example, thin-layer chromatography as described above, liquid chromatographic separation comprising adding the asymmetry recognition agent to a mobile phase, micelle dynamic chromatography that is one kind of capillary electrophoresis, and the like. [0010] This reason is that the UV absorption of an intended substance is relatively minimized so as to be undetectable when a large UV absorption, as represented by the aromatic group, is present in a background (corresponding to a thin layer or mobile phase) in a generally extensively used UV detector. Accordingly, a polysaccharide derivative-based asymmetry recognition agent having high asymmetric recognition ability and minimized UV absorption has been demanded so as to be applicable to the chiral CE field and chiral TLC field. [0011] The present invention thus has an object to provide a separating agent for enantiomeric isomers free from large UV absorption as represented by an aromatic group and having high asymmetry recognition ability, particularly high asymmetry recognition ability in an aqueous mobile phase. DISCLOSURE OF THE INVENTION [0012] As a result of eager studies for achieving the above-mentioned object, the present inventors have now achieved the present invention. [0013] Namely, the present invention provides a separating agent for enantiomeric isomers comprising a polysaccharide alicyclic ester derivative free from aromatic group as an effective component. [0014] The polysaccharide alicyclic ester derivative free from an aromatic group is specifically cellulose tris(cyclohexyl-carboxylate), cellulose tris(cyclopentylcarboxylate) or cellulose tris(cycloadamantylcarboxylate). [0015] The present invention further provides a method for separating enantiomeric isomers by chromatography using a chiral stationary phase containing a polysaccharide alicyclic ester derivative free from an aromatic group as an effective component, or a use for a polysaccharide alicyclic ester derivative free from an aromatic group as a separating agent for enantiomeric isomers. DETAILED DESCRIPTION OF THE INVENTION [0016] Hereinafter, embodiments of the present invention will be described in detail. [0017] The polysaccharide alicyclic ester derivative free from an aromatic group used in the present invention can be obtained by reacting a polysaccharide with an alicyclic compound having a functional group that is reactive with the hydroxyl group of the polysaccharide to form an ester bond. [0018] The polysaccharide used in the present invention may be any polysaccharide, such as a synthetic or natural one or a modified natural one as long as it has optical activity. The polysaccharide has preferably a high regularity in the manner of binding between saccharides. Examples of the polysaccharide include .beta.-1,4-glucan (cellulose), .alpha.-1,4-glucan (amylose or amylopectin), .alpha.-1,6-glucan (dextran), .beta.-1,6-glucan (pustulan), .beta.-1,3-glucan (for example, curdlan, schizophyllan, etc.), .alpha.-1,3-glucan, .beta.-1,2-glucan (crown gall polysaccharide), .beta.-1,4-galactan, .beta.-1,4-mannan, .alpha.-1,6-mannan, .beta.-1,2-fructan (inulin), .beta.-2,6-fructan (levan), .beta.-1,4-xylan, .beta.-1,3-xylan, .beta.-1,4-chitosan, .alpha.-1,4-N-acetylchitosan (chitin), pullulan, agarose and alginic acid. Also, starches containing amylose are included therein. Among these polysaccharides, it is preferable to use cellulose, amylose, .beta.-1,4-xylan, .beta.-1,4-chitosan, chitin, .beta.-1,4-mannan, inulin, curdlan, etc. which can be easily obtained as highly pure polysaccharides, still preferably cellulose. [0019] It is preferable that such a polysaccharide has a number-average degree of polymerization (i.e., the average number of pyranose or furanose rings per molecule) of at least 5, still preferably, at least 10. From the viewpoint of handling properties, it is preferable that the number-average degree of polymerization thereof is not more than 1,000, though the upper limit thereof is not particularly defined. [0020] As the alicyclic compound having a functional group capable of reacting with the hydroxyl group of the polysaccharide to form an ester bond, which is used in the present invention, any compound may be used as long as it has a functional group capable of forming an ester bond, such as an acid halide having an alicyclic structure free from large UV absorption represented by an aromatic group, or the like. To impart the effect for regularly aligning the polysaccharide derivative frames or substituents, an alicyclic compound having a ring larger than 3-membered ring, more preferably larger than 5-membered ring, or an alicyclic compound having a cross-linking structure is desirable. Particularly preferable examples of the polysaccharide alicyclic ester derivative not having a large UV absorption represented by an aromatic group, which is used in the present invention, include ester derivatives of polysaccharides having at least 0.1 ester bond per glucose unit, particularly, cycloalkylcarboxylates of polysaccharides. Specifically, they include cyclohexyl-carboxylate, cyclopentylcarboxylate and cycloadamantylpentyl-carboxylate. Continue reading about Separating agent for enantiomeric isomers... Full patent description for Separating agent for enantiomeric isomers Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Separating agent for enantiomeric isomers patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Separating agent for enantiomeric isomers or other areas of interest. ### Previous Patent Application: Porous hybrid monolith materials with organic groups removed from the surface Next Patent Application: Systems and methods for packing chromatography columns Industry Class: Liquid purification or separation ### FreshPatents.com Support Thank you for viewing the Separating agent for enantiomeric isomers patent info. 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