JPH08259470A - Reagent for optical resolution - Google Patents

Abstract

PURPOSE: To obtain a reagent for optical resolution by polymerizing a chemically modified saccharide on the surface of a porous carrier, insoluble in an organic solvent, slightly restricting a solvent to dissolve a developing solution for liquid chromatography and a specimen. CONSTITUTION: A polysaccharide derivative obtained by introducing a vinyl group through an ester bond or a urethane bond to a hydroxyl group part of a polysaccharide (e.g. cellulose) having optical resolution ability is polymerized on the surface of a porous carrier (preferably silica gel or porous glass into which vinyl group is introduced) and a layer comprising the polymerization product of the polysaccharide derivative is formed on the surface of the carrier to give the objective reagent for optical resolution. To be concrete, for example, a cellulose is reacted with 4-vinylbenzoyl chloride to give 4-vinylbenzoylated cellulose, which is adsorbed on the surface of N-acryloylaminopropylated silica gel obtained by reacting silica gel successively with aminopropyltriethoxysilane and acryloyl chloride and polymerized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an optical resolving agent, and more particularly to a high-performance liquid chromatograph obtained by polymerizing a vinyl derivative of a polysaccharide having optical resolving ability such as cellulose on a porous carrier (particles). The present invention relates to an optical resolving agent suitable as a filler for lithography.

[0002]

BACKGROUND ART Hitherto, polysaccharides such as starch, dextran, cellulose and cellulose derivatives have specific optical resolving power, and it has been disclosed that they are useful as an optical resolving agent in JP-A-60-40952. Publication No.
-82858 publication, "Separation of optical isomers" edited by The Chemical Society of Japan [Quarterly Chemical Review No. 6] pp. 167-175 (1989), etc.
Among them, it is generally recognized that a derivative obtained by esterifying a hydroxyl group of cellulose, for example, a chemically modified cellulose such as cellulose triacetate has higher optical resolution than that of cellulose itself.

[0003] In the direct resolution of optical isomers by liquid chromatography, when the above-mentioned substance having optical resolving ability is used as it is as a filler for liquid chromatography, the pressure-resistant surface and the solvent Due to swelling and shrinking due to
Therefore, a method of supporting the above substance on a carrier that does not cause such a problem and using it is generally considered.

Under these circumstances, the simplest method for supporting the above-mentioned substance on a carrier is a physical method of impregnation adsorption, that is, after immersing the carrier in a solution in which the substance is dissolved, Can be considered a method of drying out, but the weak point of this method is that the solvent type that dissolves the above-mentioned substance is difficult to use, and the width of the solvent that can be used during the chromatographic measurement operation is narrow. Is generally larger in chemically modified polysaccharides. That is, since the modified polysaccharide is easily dissolved in an organic solvent, it is necessary to use a developing solution that does not dissolve the modified polysaccharide, and the selection of separation conditions is significantly restricted. There is also a limitation in the selection of the polysaccharide derivative, and there is an inherent problem that the number of theoretical plates is significantly reduced only by injecting a few μl of a good solvent into the polysaccharide derivative.

As a method for eliminating such weaknesses in the physical method, a method in which a carrier and a polysaccharide derivative are chemically bonded can be considered. However, a polysaccharide derivative can be used while maintaining its excellent optical resolution. On the other hand, no specific method has been proposed so far on how to chemically bond to the carrier. For example, in the above-mentioned JP-A-60-82858, as a method for holding a polysaccharide derivative on a carrier, a chemical method can be adopted in addition to a physical method. Has not specifically disclosed such a chemical method.

[0006]

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for optical resolution which has less restrictions on a developing solution and a solvent for dissolving a sample in liquid chromatography. It is an object of the present invention to provide an optical resolution carrier using an agent, in particular, a chemically modified polysaccharide (polysaccharide derivative).

[0007]

That is, as a result of intensive studies made by the present inventors, for the purpose of insolubilizing a polysaccharide used as an optical resolving agent, in particular, a chemically modified polysaccharide, a hydroxyl group of the polysaccharide is converted to a predetermined group having a vinyl group. By chemically modifying the polysaccharide derivative with a vinyl group introduced through an ester bond or a urethane bond on the surface of the porous carrier, it is chemically modified using a modifying agent, whereby a conventional chemically modified polysaccharide is obtained. The present inventors have found that it is possible to obtain a polymer optically active carrier that is completely insoluble even in solvents such as ethyl acetate, tetrahydrofuran, methylene chloride, chloroform, acetone and the like, which exhibit high solubility, and complete the present invention. It was reached.

Therefore, the optical resolving agent according to the present invention is characterized in that a polysaccharide having an optical resolving ability is used and a vinyl group is introduced into the hydroxyl group via an ester bond or a urethane bond. The derivative is polymerized on the surface of the porous carrier, and a layer composed of a polymerization product of such a polysaccharide derivative is formed on the surface of the porous carrier. Such a polysaccharide derivative is copolymerized with a porous carrier into which a vinyl group has been introduced, and on the surface of the porous carrier,
A layer of a polymerization product formed by such copolymerization is formed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION By the way, in the present invention, as the polysaccharide into which a vinyl group is introduced, any known one having optical resolution is targeted, and cellulose is a typical one. In addition, polysaccharides such as dextran, amylose, curdlan, pullulan and the like can be used appropriately. In addition, chemically modified cellulose, which is obtained by chemically modifying cellulose as a polysaccharide, has an increased molecular weight, the viscosity of the solution increases, and it becomes difficult to uniformly adhere and adsorb the porous carrier surface. In order to uniformly apply a uniform cellulose derivative to the surface of the porous carrier, it is desirable in the present invention to use cellulose having a low molecular weight, for example, having a number average polymerization degree of about 100 or less.

In order to chemically modify such a polysaccharide to introduce a vinyl group, the hydroxyl group is vinyl-bonded via an ester bond or a urethane bond so as not to impair its excellent optical resolution. It is necessary to introduce a group (specifically, a vinyl group-containing organic group).

In order to chemically modify the polysaccharide, a known vinyl compound which reacts with a hydroxyl group of the polysaccharide to form an ester bond or a urethane bond is appropriately selected. For example, acryloyl chloride, methacryloyl chloride, etc. And unsaturated acid halides such as vinylbenzoyl chloride and unsaturated isocyanates such as vinylphenyl isocyanate.In addition, not only compounds having one vinyl group in the molecule but also a plurality of A compound having a vinyl group can also be used if necessary, and even when a vinyl compound having a structure in which the vinyl group is bonded to a benzene ring is used, if the vinyl group can be polymerized at the bonding position, No significant inconvenience is manifested at any position of the vinyl group, ortho, meta, para.

In the case where the polysaccharide is chemically modified with a compound having a vinyl group, the number of polysaccharides introduced into the polysaccharide structural unit may be all hydroxyl groups present in the polysaccharide structural unit, such as cellulose. In the case of (3), it is not necessary to completely chemically modify the three hydroxyl groups.After the chemical modification, the three hydroxyl groups are chemically modified to such an extent that they can be dissolved in a good solvent such as methylene chloride, so that polymerization on the target carrier surface is achieved. Is achievable.

On the other hand, in the present invention, the porous carrier to which the vinyl group-introduced polysaccharide is applied is a porous inorganic carrier such as silica, alumina, magnesia, titanium oxide, glass, silicate, kaolin, polystyrene, or the like. Although there are known ones such as porous organic carriers such as polyamide and polyacrylate, generally, porous particles such as silica (silica gel) and glass (porous glass) are preferably used.

In the present invention, such a porous carrier is used as it is, and a vinyl group is introduced into the porous carrier so that the vinyl group-introduced polysaccharide is more effectively supported. Copolymerization between the group-introduced polysaccharide and the vinyl group-introduced porous carrier is achieved, and a more effective organic solvent-insolubilizing optical resolving agent is provided.

In introducing a vinyl group into the porous carrier, various known techniques are employed, and the function of copolymerizing is not affected as in the above-mentioned method of bonding a vinyl group to a polysaccharide. To the extent, using a vinyl compound having a plurality of vinyl groups and vinyl groups at various bonding positions, such a vinyl compound, for a given porous carrier,
Preferably, the target vinyl group is introduced by reacting with a chemically modifiable carrier such as silica gel or porous glass and chemically bonding it.

Here, a more specific method of introducing a vinyl group into the porous carrier will be described as follows, taking silica gel as an example.

[0017]

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[0018]

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[0019]

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Accordingly, since the present invention uses the above-described porous carrier, the method for synthesizing an optical resolving agent obtained by polymerizing a vinyl group-introduced polysaccharide as described above uses a vinyl carrier as the porous carrier. The method is roughly divided into a method using a carrier having a group bonded thereto and a method using a carrier having no vinyl group. For these synthetic methods, the carrier having a vinyl group introduced and the unmodified carrier have different polarities on the surface of the carrier, and therefore, particularly when adsorbing a polysaccharide having a vinyl group introduced,
The adsorption amount and the degree of desorption of the vinylated polysaccharide at the time of polymerization may be different, but the adsorption method and the polymerization conditions can be applied by the same method. Then, after adhering or adsorbing to the above, the polymerization is carried out by employing a polymerization technique such as radical polymerization, ionic polymerization, plasma polymerization or the like.

When an unmodified porous carrier is used, if the degree of polymerization is increased to such an extent that it does not dissolve in a good solvent such as methylene chloride, the purpose of not dissolving in such a good solvent can be achieved. On the other hand, when the degree of polymerization is low,
The possibility exists that the polysaccharide derivative elutes.
In addition, when a carrier having a vinyl group introduced is used, even when the polymerization does not reach a degree of polymerization that does not dissolve in a good solvent, the polysaccharide derivative will bind to the carrier, and thus elution should be avoided. I can do it.

Further, since it is considered that all of the polysaccharide derivative and the vinyl group bonded to the surface of the carrier are not polymerized and disappear by one polymerization, the optical resolving agent obtained by the polymerization treatment is used. Further, a method of further increasing the degree of polymerization by adsorbing a polysaccharide having a vinyl group bonded thereto, increasing the amount of the polysaccharide derivative introduced, and polymerizing the polysaccharide derivative can be employed. In a method of performing such polymerization a plurality of times, in addition to a polysaccharide having a vinyl group bonded thereto, a compound having a plurality of vinyl groups, for example, divinylbenzene, ethylenediamine dimethacrylate, using a crosslinking agent such as ethylene glycol diacrylate. Means for accelerating the crosslinking reaction and decreasing the solubility in good solvents can also be employed.

As the polymerization conditions for synthesizing the polymerization type optical resolving agent according to the present invention, the conditions used for general suspension polymerization can be applied. The ester group bonded to the saccharide may be hydrolyzed, and further, the vinyl group-introduced polysaccharide adsorbed on the porous carrier by hydrogen bonding may form a hydrogen bond between the polysaccharide and the porous carrier by the intervention of water. Is expected to fall off the surface of the porous carrier by being cut. The loss of a functional group containing a vinyl group introduced into the polysaccharide leads to a decrease in optical resolution, and a decrease in the amount of vinylated polysaccharide adsorbed on the porous surface in the polymerization step causes a decrease in the amount of adsorption on the porous surface. It is thought to cause a decrease in the introduction efficiency of the polysaccharide derivative. From the above, the polymerization of the polysaccharide derivative on the porous surface does not hydrolyze the ester bond or urethane bond and does not reduce the adsorption amount of the polysaccharide derivative, as compared with the method using water as a medium. It is desirable to select a suitable solvent.

As a polymerization medium which does not inhibit the decomposition of ester bonds and urethane bonds and the hydrogen bond, use of a low-polarity organic solvent can be mentioned.
That the polysaccharide derivative is soluble in relatively many organic solvents,
Also, in consideration of ensuring the reaction temperature required in radical polymerization, a solvent having a boiling point of 90 ° C. or higher and a liquid at room temperature is desirable. From these facts, as the organic solvent, alkyl hydrocarbons are considered to be optimal as a medium used for the synthesis of the intended optical resolving agent, and as specific alkyl hydrocarbon solvents,
A mixture of straight-chain hydrocarbons having 7 or more carbon atoms, such as heptane, octane, nonane, and decane, branched hydrocarbons such as isooctane, cyclic hydrocarbons such as decalin, and hydrocarbons such as kerosene is used for polymerization. It is advantageously used.

In this way, by polymerizing the vinyl group-introduced polysaccharide derivative attached or adsorbed to the surface of the porous carrier, polymerization of such a polysaccharide derivative is carried out on the surface of the porous carrier. A layer formed of the product is formed, and particularly when the vinyl group is introduced into the porous carrier, copolymerization is also carried out between the carrier and the polysaccharide derivative, which is no longer organic. Since it becomes insoluble in the solvent, the optical resolving agent insolubilized in the organic solvent can be advantageously obtained here.

In fact, as a result of applying such an insoluble polysaccharide-polymerizable optically active carrier according to the present invention to a packing material for high performance liquid chromatography, as a result of simply adsorbing a chemically modified polysaccharide on a conventional silica gel base material. The optical resolution can be achieved even under mobile phase conditions in which the polysaccharide derivative is dissolved in the optical resolving agent and no resolving ability is expressed at all, and it is a representative of good solvents for the polysaccharide derivative before polymerization. It has been confirmed that even when a certain methylene chloride is injected and passed, the performance does not deteriorate and the polymer-type carrier maintains the optical resolution.

[0027]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it should be understood that the present invention is not in any way restricted by the description of such Examples. Needless to say. Further, the present invention, in addition to the following examples, further, in addition to the above specific description, without departing from the gist of the present invention,
It should be understood that various changes, modifications, improvements, and the like can be made based on the knowledge of those skilled in the art.

Example 1 Acetylcellulose was hydrolyzed to have a low molecular weight and then the acetyl group was removed to obtain a low molecular weight cellulose (polymerization degree: about 36). Disperse in 250 ml, add 89.0 g of 4-vinylbenzoyl chloride, heat to 80 ° C., stir 1
The reaction was performed for 0 hours. After the reaction, the reaction solution is methanol 1
It was poured into 000 ml to precipitate 4-vinylbenzoylated cellulose, which was washed with methanol while sucking and filtering, and dried at 50 ° C. After this drying, methylene chloride 5
After dissolving in 00 ml and filtering off insolubles, methylene chloride was distilled off and methanol was added to precipitate a solid. The cellulose derivative thus obtained includes FT-I
From the measurement of the R spectrum, absorption of a carbonyl group was observed, and it was confirmed that the hydroxyl group of glucose, which is a structural unit of cellulose, was derivatized.

Then, using the obtained 4-methylbenzoylated cellulose, 1 g of the cellulose was added to 50 m of methylene chloride.
4 g of silica gel as a porous carrier was added to the solution obtained by dissolving the solution in 1 l, and the mixture was dispersed. Then, methylene chloride was distilled off under reduced pressure at 30 ° C., and the cellulose derivative was adhered and adsorbed on the silica gel surface. Was.

Thereafter, 3 g of the silica gel adsorbing the 4-vinylated cellulose was dispersed in 50 ml of n-heptane, 30 mg of benzoyl peroxide was added, and the mixture was polymerized at 80 ° C. for 4 hours with stirring. A layer composed of a polymerization product of 4-vinylbenzoylated cellulose was formed on the surface of the silica gel carrier. After the polymerization reaction, the silica gel on which the polymerization product layer was formed was washed with methylene chloride and dried under reduced pressure.

The silica gel on which the phase of the polymerization product of 4-vinylbenzoylated cellulose thus obtained was formed, was subjected to a dissolution test, and was found to be simply acetylcellulose,
Compared to silica gel in which low molecular weight cellulose or 4-vinylbenzoylated cellulose is only adsorbed on the surface, it shows excellent insolubility in organic solvents, and even if the adsorbed cellulose derivative is polymerized, its optical resolution It has been found that can be well maintained.

Example 2 As a vinyl group-introduced porous carrier, N-acryloylaminopropylated silica gel was synthesized as follows.

That is, first, 2 g of silica gel dried under reduced pressure was dispersed in 100 ml of toluene, 2 g of aminopropyltriethoxysilane as a silylating agent was added, and ethanol produced by the reaction of the silylating agent and silanol was added. First, aminopropylated silica gel was synthesized by reacting for 5 hours while distilling off with toluene. After the reaction, the reaction mixture was washed with methanol, 80% methanol, methanol, and chloroform in that order, and dried under reduced pressure.

Then, 2 g of the aminopropylsilylated silica gel was dispersed in 50 ml of chloroform, 2 ml of acryloyl chloride was added thereto, and the mixture was reacted at 80 ° C. for 2 hours to obtain N-acryloylaminopropyl silica gel. After the reaction, the resultant was washed with methanol and chloroform in that order, and dried under reduced pressure.

Then, using the N-acryloylaminopropylated silica gel thus obtained, the 4-vinylbenzoylated cellulose synthesized in Example 1 was adsorbed on the surface thereof. 1 g was dissolved in 50 ml of methylene chloride, and the above-mentioned N-acryloylaminopropylated silica gel was further added and dispersed therein. Then, methylene chloride was distilled off at 30 ° C. under reduced pressure to remove the cellulose derivative on the silica gel surface. Adsorbed.

Thereafter, 3 g of N-acryloylaminopropyl silica gel to which the 4-vinylbenzoylated cellulose was adsorbed was dispersed in 50 ml of n-heptane, and 30 mg of benzoyl peroxide was added thereto. Acryloyl group (vinyl group) introduced into silica gel by polymerizing at 80 ° C for 4 hours
Copolymerization between the polymer and 4-vinylbenzoylated cellulose was carried out to obtain a polymerization type optical resolving agent in which a cellulose derivative was chemically bonded to the surface of silica gel.

The polymerization type optical resolving agent thus obtained is
Optical separation consisting of silica gel with only 4-vinylbenzoylated cellulose adsorbed on the surface, using as a packing material to be packed in a column of a high-performance liquid chromatography device and examining the effect of methylene chloride injection on the theoretical plate number and retention. The investigation was made in comparison with the case where the agent was used as an adsorption type filler. That is, the influence of the injection of methylene chloride on the theoretical plate number of benzene and the retention time of stilbene oxide in the adsorption type and polymerization type cellulose derivative fillers was examined, and the results are shown in FIGS. 1 and 2.

As is apparent from FIGS. 1 and 2,
In the adsorption type filler, the theoretical plate number decreased from about 8300 plates to about 3000 plates when 20 μl of methylene chloride was injected, and decreased to 1000 plates or less when 200 μl was injected. This can be presumed to be because the injection of methylene chloride partially dissolved the cellulose derivative and disturbed the stationary phase, resulting in a decrease in the number of theoretical plates. Regarding the retention time, injection of about 20 to 50 μl has no effect on the retention time, and it is considered that the cellulose derivative is not eluted. However, when 100 μl or more of methylene chloride was injected at one time, retention decreased sharply and elution of the cellulose derivative was observed. This result suggests that methylene chloride cannot be used as the solvent for dissolving the sample in the adsorption-type filler, and it can be inferred that such a decrease also occurs for solvents having a solubility parameter of around 18 to 25. I can do it.

On the other hand, in the case of the polymerizable filler of the chemical bond type according to the present invention, no difference is observed in the retention time, the number of theoretical plates, and the optical resolution, and the filler is extremely excellent in solubility in organic solvents. That became clear.

Further, as a result of examining the presence or absence of optical resolution in a mobile phase using tetrahydrofuran which is a good solvent as an additive for the cellulose derivative, as shown in FIG. 3 and FIG. When the agent is used, the optical resolving power is exhibited even in the mobile phase to which 30% of tetrahydrofuran (THF) is added, and the optical resolving power is maintained even when the added amount is further increased to 50%. confirmed. The liquid chromatography conditions were as follows:
It was as follows. Column: Polymerization type vinyl benzoyl cellulose Column size: 4.6 mm (inner diameter) -150 mm
(Length) Mobile phase: Hexane / THF = 7/3 (Fig. 3) Hexane / THF = 5/5 (Fig. 4) Flow rate: 1.0 ml / min Detection: UV 254 nm Test material: Warfarin

On the other hand, in the case of using the adsorptive filler in which 4-vinylbenzoylated cellulose was simply adsorbed, the elution of the stationary phase was observed even with the addition of 30% of tetrahydrofuran, and the retention was reduced. Due to the turbulence of the baseline, chromatographic analysis was not possible.

[0042]

As is clear from the above description, the optical resolving agent obtained by polymerizing a polysaccharide derivative on the surface of a porous carrier according to the present invention is prepared by adsorbing on a conventional porous carrier surface. Has the same optical resolution as that of the adsorption-type resolving agent, and also does not dissolve polysaccharide derivatives in organic solvents that cannot be used with such conventional adsorption-type resolving agents. It is a very useful polysaccharide derivative-type resolving agent that can be used.

[Brief description of drawings]

FIG. 1 is a graph showing the change in the theoretical plate number and the retention ratio with respect to the methylene chloride injection amount obtained in Example 2.

FIG. 2 is another graph showing changes in the number of theoretical plates and the retention ratio with respect to the injection amount of methylene chloride, which was obtained in Example 2.

FIG. 3 is a chromatogram obtained when the composition of the mobile phase obtained in Example 2 is hexane / THF = 7/3.

FIG. 4 is a chromatogram obtained when the composition of the mobile phase obtained in Example 2 was hexane / THF = 5/5.

Claims (2)

[Claims] 1. A polysaccharide derivative obtained by introducing a vinyl group into its hydroxyl group via an ester bond or a urethane bond by using a polysaccharide having optical resolution, is polymerized on the surface of a porous carrier, An optical resolving agent, characterized in that a layer comprising a polymerization product of such a polysaccharide derivative is formed on the surface of the porous carrier. 2. A polysaccharide derivative obtained by introducing a vinyl group into its hydroxyl group site through an ester bond or a urethane bond, using a polysaccharide having optical resolution, to a porous carrier having a vinyl group introduced therein. Copolymerized,
An optical resolving agent, wherein a layer of a polymerization product produced by such copolymerization is formed on the surface of the porous carrier.