JPH10249191A - Separating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the tailing of a compd. to be analyzed and to attain satisfactory separation by using a separating agent made of a polysaccharide deriv. carried on modified silica gel having a specified carbon content as a carrier. SOLUTION: A polysaccharide deriv., preferably an ester or carbamate deriv., especially preferably amylose tris (3,5-dimethylphenylcarbamate) is carried on modified silica gel having >=1.8wt.%, preferably 1.8 to about 5.0wt.% carbon content as a carrier. The size of the modified silica gel depends on the size of a column used but the particle diameter of the silica gel is usually 1μm to about 10mm, preferably 1μm to about 300μm. The silica gel is preferably porous and the pref. average pore diameter is 10Å to 100μm, especially about 50-50,000Å.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separating agent comprising a polysaccharide derivative supported on a carrier, and in particular, the carrier supporting the polysaccharide derivative comprises a modified silica gel having a specific carbon content, and is useful for optical resolution of a racemate. The present invention relates to a novel separating agent.

[0002]

BACKGROUND OF THE INVENTION It has been known that a separating agent comprising a polysaccharide derivative is useful as a separating agent for optical isomers (Y. OKAMOTO, MK).
AWASHITA AND K.HATADA, J. Am. Chem. Soc., 106, 5357
-5359, 1984, JP-B-63-12850). This polysaccharide derivative is usually used by being supported on a silica gel carrier, has a very high optical resolution for a racemic form, and is widely used for analysis and fractionation of optical isomers. In general, the silica gel carrier often protects and modifies the residual silanol groups in order to minimize the influence of the residual silanol groups inherent in silica gel. However, regarding the protection of the residual silanol group, it is difficult to set the optimum modification rate, and thus it is not particularly specified. In the case where the compound to be analyzed is a basic compound, particularly a strongly basic compound, tailing is suppressed. For this reason, there has been a problem that a treatment such as adding a low-boiling basic compound such as diethylamine to the mobile phase solvent has to be performed.

[0003] Further, in the case of fractionation of optical isomers, suppression of tailing is a major problem in increasing the fractionation efficiency, and as in the case of analysis, low boiling basic compounds such as diethylamine are used in the mobile phase solvent. Compound was added. Therefore, in obtaining a fraction, it was necessary to remove not only the mobile phase solvent but also the low-boiling basic compound used as an additive.

Accordingly, an object of the present invention is to provide a separation agent comprising a polysaccharide derivative supported on a modified silica gel carrier without tailing of a compound to be analyzed without performing a treatment for suppressing tailing, resulting in good separation. It is to provide the obtained separating agent.

[0005]

Means for Solving the Problems In order to solve the above problems, the present inventors have made intensive studies on a separating agent which can maximize the useful properties of the modified silica gel and overcome the above problems. The present invention has been reached. That is, the present invention provides a separating agent comprising a polysaccharide derivative supported on a carrier, wherein the carrier is a modified silica gel having a carbon content of 1.8% by weight or more.

[0006]

Embodiments of the present invention will be described below in detail.

[0007] The polysaccharide in the present invention may be any optically active polysaccharide, regardless of any of synthetic polysaccharide, natural polysaccharide and natural product-modified polysaccharide, but those having a high degree of regularity in the binding mode are preferred. To illustrate such a polysaccharide,
β-1,4-glucan (cellulose), α-1,4-glucan (amylose, amylopectin), α-1,6-glucan (dextran), β-1,6-glucan (Bussullan), β-1, 3-glucan (curdlan, schizophyllan), α-1,3-glucan, β-1,2-glucan (Crow
n Gall polysaccharide), β-1,4-galactan, β-1,4-mannan, α-1,6-mannan, β-1,2-fractane (inulin), β-2,6-fractan (levan) , Β−1,4
-Xylan, β-1,3-xylan, β-1,4-chitosan, β-1,4-N-acetylchitosan (chitin), pullulan, agarose, alginic acid, α-cyclodextrin, β-cyclodextrin, γ -Cyclodextrin and the like, and also starches containing amylose and the like. Among these, preferred are cellulose, amylose, β-1,4, from which a high-purity polysaccharide can be easily obtained.
− Chitosan, chitin, β-1,4- mannan, β-1,4 −
Xylan, inulin, curdlan, etc., more preferably, cellulose and amylose, particularly preferably amylose.

[0008] The polysaccharide derivative in the present invention is a compound obtained by bonding a compound having a functional group capable of reacting with a hydroxyl group of a polysaccharide with an ester bond, a urethane bond or the like by a known method. . Here, the compound having a functional group capable of reacting with a hydroxyl group includes aliphatic, alicyclic, aromatic and heteroaromatic isocyanic acid derivatives, carboxylic acids, esters, acid halides, acid amides, halides, and epoxides. Aldehydes, alcohols and other compounds having a leaving group.

Particularly preferred polysaccharide derivatives are ester derivatives or carbamate derivatives, and amylose tris (3,5-dimethylphenylcarbamate) is more preferred.

In the present invention, the average degree of polymerization of the polysaccharide (the average number of pyranose or furanose rings contained in one molecule) is 5 or more, preferably 10 or more, and there is no particular upper limit.
It is preferable that it is 500 or less in terms of ease of handling. The weight average molecular weight (in terms of polystyrene) of the polysaccharide derivative in the present invention is preferably from 1,000 to 500,000, and more preferably from 20,000 to 500,000. The molecular weight distribution (in terms of polystyrene) of the polysaccharide derivative in the present invention is preferably from 1 to 3, more preferably from 1 to 1.1.

In the present invention, the modified silica gel used as a carrier has a carbon content of 1.8% by weight or more, preferably
1.8 to 5.0% by weight. If modified silica gel having a carbon number content of less than 1.8% by weight is used, tailing cannot be suppressed.

The size of the modified silica gel used in the present invention varies depending on the size of the column used, but it is generally 1 μm to 10 mm, preferably 1 μm to 300 μm.
The modified silica gel is preferably porous, and the average pore size is preferably from 10 to 100 µm, more preferably from 50 to 50,000 µm.

As the modified silica gel used in the present invention, those obtained by subjecting the surface of silica gel to silanization treatment with an organic silane compound or those subjected to surface treatment by plasma polymerization may be mentioned. Particularly preferred modified silica gel has been subjected to two-stage treatment of aminopropylsilane treatment and carbamoyl treatment.

In the present invention, the amount of the polysaccharide derivative supported on the carrier is preferably 1 to 100% by weight based on the carrier.
More preferred is 5 to 50% by weight. The method for supporting the polysaccharide derivative on the carrier may be a chemical method or a physical method. As a chemical method, there is a method in which some hydroxyl groups are protected when derivatizing a polysaccharide, derivatized, deprotected, and chemically bonded to silica gel (Y. Okamoto). et al., J. Mol.
Liq. Chromatogr. , 10 (8 &
9), 1613, 1987). As a physical method, there is a method in which a polysaccharide derivative is dissolved in a soluble solvent, mixed well with a carrier, and the solvent is distilled off under reduced pressure, heated, or in an air stream.

The separating agent of the present invention is suitably used particularly for liquid chromatography, and the eluent for liquid chromatography is not particularly limited, except for a liquid that dissolves or reacts with the separating agent. When the separating agent is chemically bonded to the carrier, there is no limitation except for the reactive liquid, but preferably a mixed solution of n-hexane, various alcohols, tetrahydrofuran and the like is used. The separating agent of the present invention is particularly useful for obtaining an optically active substance by optically resolving a racemate.

[0016]

The separating agent comprising the polysaccharide derivative supported on the specific modified silica gel according to the present invention can provide good separation without tailing of the compound to be analyzed.

[0017]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but it goes without saying that the present invention is not limited to these Examples. The parameters k ′, α and Rs used in the examples are defined as follows.

[0018]

(Equation 1)

Example 1 <Synthesis of polysaccharide derivative> 2 g of amylose was dissolved in pyridine.
It was heated and reacted with 17 g of 3,5-dimethylphenyl isocyanate for 30 hours. The reaction product was poured into the mixture with stirring under methanol to precipitate, collected by filtration through a G4 glass filter, washed twice with methanol, and dried in vacuo at 80 ° C. for 5 hours.
Pyridine was added to the obtained product to dissolve completely, and the mixture was poured again with stirring under methanol to precipitate. The precipitate was collected by filtration with a G4 glass filter, washed twice with methanol, and then washed with methanol at 80 ° C. for 5 times.
After vacuum drying for a time, a purified product amylose tris (3,5-dimethylphenylcarbamate) was obtained.

<Preparation of Separating Agent Having Polysaccharide Derivative Supported on Modified Silica Gel> The above amylose tris (3,5-dimethylphenylcarbamate) was converted into chloroform / N, N-
Dimethylacetamide was dissolved in 99/1 (v / v), and this solution was subjected to two-stage treatment of aminopropylsilane treatment and carbamoyl treatment, and modified silica gel having a carbon content of 2.17% by weight (manufactured by Daiso Corporation, particle size After uniformly sprinkling the solution over a pore size of 20 μm and a pore size of 1300 °), the solvent was distilled off to obtain a separating agent in which amylose tris (3,5-dimethylphenylcarbamate) was supported on the modified silica gel. The carbon content is a value obtained by elemental analysis (using Yanaco CHN CORDER MT-5).

<Preparation of Optical Separation Column> The separating agent in which the above amylose tris (3,5-dimethylphenylcarbamate) is supported on the modified silica gel is 25 cm in length and 1 cm in inner diameter.
An optical splitting column was prepared by filling a stainless steel column having a diameter of 1.0 cm by a slurry filling method.

<Evaluation of Performance of Optical Resolution Column> Using the above-mentioned optical resolution column, an optical resolution experiment was performed on verapamil, dimethothiazine and chlorpheniramine. JASCO 875-UV manufactured by JASCO was used for the performance evaluation, hexane / 2-propanol = 90/10 (v / v), and the flow rate was 4.7 ml /
min., temperature was 25 ° C. The results are shown in Table 1.

Example 2 <Synthesis of polysaccharide derivative> Amylose tris (3,5-dimethylphenylcarbamate) was obtained in the same manner as in Example 1.

<Preparation of Separating Agent Supporting Polysaccharide Derivative on Modified Silica Gel> The above amylose tris (3,5-dimethylphenylcarbamate) was added to chloroform / N, N-
This solution was dissolved in dimethylacetamide = 99/1 (v / v), and this solution was subjected to aminopropylsilane treatment and carbamoyl treatment in two steps, and modified silica gel having a carbon content of 2.40% by weight (Daiso, particle size After uniformly sprinkling the solution over a pore size of 20 μm and a pore size of 1300 °), the solvent was distilled off to obtain a separating agent in which amylose tris (3,5-dimethylphenylcarbamate) was supported on the modified silica gel. The carbon content is a value obtained by elemental analysis (using Yanaco CHN CORDER MT-5).

<Preparation of Optical Resolution Column> An optical resolution column was prepared in the same manner as in Example 1 by using the above-mentioned separating agent in which amylose tris (3,5-dimethylphenylcarbamate) was supported on modified silica gel. .

<Evaluation of Performance of Optical Resolution Column> Using the above-mentioned optical resolution column, an optical resolution experiment of verapamil, dimethothiazine and chlorpheniramine was carried out in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 <Synthesis of polysaccharide derivative> Amylose tris (3,5-dimethylphenylcarbamate) was obtained in the same manner as in Example 1.

<Preparation of Separating Agent Having Polysaccharide Derivative Supported on Modified Silica Gel> The above amylose tris (3,5-dimethylphenylcarbamate) was mixed with chloroform / N, N-
Dimethylacetamide was dissolved in 99/1 (v / v), and this solution was subjected to two-stage treatment of aminopropylsilane treatment and carbamoyl treatment, and a modified silica gel having a carbon content of 1.56% by weight (manufactured by Daiso Corporation, particle size After uniformly sprinkling the solution over a pore size of 20 μm and a pore size of 1300 °), the solvent was distilled off to obtain a separating agent in which amylose tris (3,5-dimethylphenylcarbamate) was supported on the modified silica gel. The carbon content is a value obtained by elemental analysis (using Yanaco CHN CORDER MT-5).

<Preparation of Optical Resolution Column> An optical resolution column was prepared in the same manner as in Example 1 by using the above-mentioned separating agent in which amylose tris (3,5-dimethylphenylcarbamate) was supported on modified silica gel. .

<Evaluation of Performance of Optical Separation Column> Using the above-described optical resolution column, an optical resolution experiment was performed on verapamil, dimethothiazine and chlorpheniramine in the same manner as in Example 1. Table 1 shows the results.

[0031]

[Table 1]

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI C07D 279/04 C07D 279/04

Claims (7)

[Claims] 1. A separating agent comprising a polysaccharide derivative supported on a carrier, wherein the carrier is a modified silica gel having a carbon content of 1.8% by weight or more. 2. The modified silica gel has a particle size of 1 μm to 10 mm,
The separating agent according to claim 1, which has a pore size of 10 to 100 µm. 3. The separating agent according to claim 1, wherein the modified silica gel has been subjected to two-stage treatment of aminopropylsilane treatment and carbamoyl treatment. 4. The separating agent according to claim 1, which is used for liquid chromatography. 5. The separating agent according to claim 1, wherein the polysaccharide derivative is a cellulose derivative or an amylose derivative. 6. The separating agent according to claim 5, wherein the polysaccharide derivative is an amylose derivative. 7. The separating agent according to claim 6, wherein the amylose derivative is amylose tris (3,5-dimethylphenylcarbamate).