JP2001226403A - Glucopyranan polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glucopyranan polymer having a narrow molecular weight distribution, capable of synthesizing an optically resolving agent and obtainable from a levoglucosan compound through a simple process, and further to provide an optical resolution agent capable of being synthesizes from the glucopyranan polymer. SOLUTION: A glucopyranan polymer expressed by a specific structure obtained by polymerizing a levoglucosan compound having a specific structure. The polymerization is carried out using a fluorinated alkylsulfonic acid as a polymerization initiator, and the molecular weigh distribution (Mw/Mn) of the resultant glucopyranan polymer is <=1.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The glucopyranan polymer of the present invention can obtain a polymer having a molecular weight distribution in a specific range from a levoglucosan compound using a specific initiator. An optical resolving agent can be synthesized from the glucopyranan polymer of the present invention.

[0002]

SUMMARY OF THE INVENTION An object of the present invention is to provide a glucopyranan polymer from a levoglucosan compound, which can easily synthesize an optical resolving agent having a narrow molecular weight distribution. Further, to provide an optical resolving agent synthesized from a glucopyranan polymer.

[0003]

According to the present invention, there is provided a compound represented by the general formula (1):
Is a glucopyranan polymer represented by the general formula (2) obtained by polymerizing a levoglucosan compound represented by the formula (1), wherein a fluorinated alkylsulfonic acid is used as a polymerization initiator and the molecular weight distribution (Mw / Mn) of the glucopyranan polymer is 1.
A glucopyranan polymer having a molecular weight of 5 or less.

Embedded image (Here, R ₁ , R _2, and R ₃ represent an alkyl group, a benzyl group, or an allyl group, and may be the same or different groups.)

Embedded image (Here, R ₁ , R _2, and R ₃ represent an alkyl group, a benzyl group, or an allyl group, and may be the same or different groups. N represents an integer of 20 or more.)

[0004] Preferably, the present invention relates to a glucopyranan polymer, wherein the levoglucosan compound is 2,3,4-tri-O-allyl-levoglucosan.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The glucopyranan polymer of the present invention is a glucopyranan polymer represented by the general formula (2) obtained by polymerizing a levoglucosan compound represented by the general formula (1), wherein a fluorinated alkyl is used as a polymerization initiator. Using sulfonic acids, the molecular weight distribution of the glucopyranan polymer (Mw /
Mn) is 1.5 or less, preferably 1.33 or less, more preferably 1.31 or less, and particularly preferably 1.29 or less.
In the present invention, a polymer having a narrow molecular weight distribution can be obtained by using a fluorinated alkylsulfonic acid as a polymerization initiator.

Embedded image (Here, R ₁ , R _2, and R ₃ represent an alkyl group, a benzyl group, or an allyl group, and may be the same or different groups.)

Embedded image (Here, R ₁ , R ₂ and R ₃ represent an alkyl group, a benzyl group or an allyl group and may be the same or different groups. The polymerization degree n is an integer of 20 or more.)

The polymerization degree n in the general formula (2) is an integer of 20 or more, preferably 25 or more, more preferably 28 or more, and particularly preferably 30 or more. R ₁ , R ₂ and R ₃ in the general formulas (1) and (2) represent an alkyl group, a benzyl group or an allyl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a hexyl group, and an octyl group.

The levoglucosan compounds represented by the general formula (1) include 2,3,4-tri-O-methyl-levoglucosan, 2,3,4-tri-O-allyl-levoglucosan and 2,3,4- Tri-O-benzyl-levoglucosan and the like can be mentioned. In particular, a glucopyranan polymer characterized in that the levoglucosan compound is 2,3,4-tri-O-allyl-levoglucosan of the general formula (3) is preferable.

Embedded image (Here, R ₁ , R ₂ and R ₃ represent an allyl group.)

Examples of the fluorinated alkyl sulfonic acids that can be used as a polymerization initiator include methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, trifluoromethanesulfonate, trifluoromethanesulfonate anhydride, trifluoromethanesulfonate chloride, and trifluoromethanesulfonate. Examples thereof include fluoroethanesulfonic acid, trifluoroethanesulfonic acid chloride, perfluorobutanesulfonic acid fluoride, and perfluorooctanesulfonic acid fluoride.
Particularly, as the fluorinated alkylsulfonic acids, methyl trifluoromethanesulfonate and ethyl trifluoromethanesulfonate are preferable.

As a polymerization solvent, toluene, methylene chloride, chloroform, dichloroethane, carbon tetrachloride, benzene, xylene and the like can be used.

The glucopyranan polymer of the present invention can synthesize an optical resolving agent by the following method. 1. The allyl group of the glucopyranan polymer is isomerized to a propenyl group by an isomerization reaction. 2. The glucopyranan polymer having an isomerized propenyl group is hydrolyzed using an acid to synthesize a glucopyranan polymer (dextran). 3. A glucopyranan polymer (dextran) is reacted with a compound capable of reacting with a hydroxyl group, and the obtained polymer can be used as an optical resolving agent.

[0011]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the glucopyranan polymer were measured by gel permeation chromatography (GPC). The measurement method is shown below. (1) Measurement device: JASCO GPC-900 was used. (2) Measurement sample: Glucopyranan polymer at room temperature,
It was dissolved in a solvent (chloroform) at a concentration of 1 mg / ml. (3) Measurement of molecular weight distribution: Measurement sample of (2) above.
1 ml of GPC column TOSOH TSK gel H
Injected into RM × 2 tubes, solvent chloroform, temperature 40
The measurement was performed at a flow rate of 1.0 ml / min. The measurement by GPC was performed for 35 minutes. The polymer concentration in the solution separated by the GPC column was measured with a differential refractometer (RI). The molecular weight was converted using a polystyrene standard. (4) Data processing: JASCO 807 data processing
-IT was used. When a baseline is drawn on the GPC chromatogram obtained in the above measurement (3), the area is integrated using data processing software attached to the apparatus, and the number average molecular weight (Mn), weight average molecular weight (Mw), Mw / Mn is calculated automatically.

Examples 1-4: 2,3,4-tri-O-
Allyl-levoglucosan under a nitrogen atmosphere, using dry methylene chloride as a polymerization solvent, and methyl trifluoromethanesulfonate (CF ₃ SO ₃ CH ₃ ) as a polymerization initiator
And cationic ring-opening polymerization was carried out under the polymerization conditions shown in Table 1. GPC measurement was performed on the obtained glucopyranan polymer, and the results are shown in Table 1. However, in Table 1, the yield (%) indicates a value calculated from the equation (1). The obtained glucopyranan polymer was analyzed by 300 MHz ¹ H-NMR and 75 MHz ¹³ C-NMR, and the results are shown in FIGS. 1 and 2. From the assignment of hydrogen atoms and carbon atoms shown in FIG. 1 and FIG. 2, the obtained glucopyranan polymer is
(1 → 6) -2,3,4-tri-O-allyl-α-D-
It was confirmed that it was glucopyranan.

[0014]

(Equation 1)

[0015]

[Table 1]

Example 5 (Synthesis of Optical Resolving Agent from Glucopyranan Polymer and Measurement of Optical Resolving Ability) Isomerization Reaction of Glucopyranan Polymer to Allyl Group to Propenyl Group To 0.59 g of the glucopyranan polymer obtained in Example 1, toluene (70 ml), ethanol (160 ml), water (2 ml), tris (triphenylphosphine) chlor 0.29 g of rhodium and diazobicyclo [2,2,2]
Add 0.69 g of octane (DABCO) and add about 7-9
Heated to reflux for an hour. The reaction solution was returned to room temperature and the solvent was distilled off. Then, the mixture was diluted with chloroform and washed with water. The chloroform solution was dried over anhydrous sodium sulfate, and the solvent was distilled off to obtain a solid. Solids 300MHz- ¹ H-NMR
The results are shown in FIG. From the assignment of hydrogen atoms shown in FIG. 3, it was confirmed that the solid was an isomerized polymer represented by the general formula (4) in which the allyl group of the glucopyranan polymer was isomerized to a propenyl group.

[0017]

Embedded image (Here, R ₆ represents a propenyl group. N represents an integer of 20 or more.)

Acid hydrolysis of isomer compound 0.1 g of the isomerized polymer is dissolved in 30 ml of acetone,
1 ml of 0.5N hydrochloric acid aqueous solution was added, and the mixture was heated under reflux for 10 minutes. After cooling to room temperature, 30 ml of acetone was added to precipitate the reaction product, and the precipitate was separated by filtration. The precipitate was dissolved in a small amount of water and purified by reprecipitation with a large amount of acetone. The precipitate is vacuum dried for 3 hours and
46 g (81% yield) were obtained. The precipitate is 300 MHz-
Analysis by ¹ H-NMR and 75 MHz- ¹³ C-NMR was performed, and the results are shown in FIGS. 4 and 5. The assignment of the hydrogen atom and the carbon atom shown in FIGS. 4 and 5 confirmed that the precipitate was (1 → 6) -α-D-glucopyranan shown in the general formula (5).

[0019]

Embedded image (Here, n represents an integer of 20 or more.)

Carbamate formation of (1 → 6) -α-D-glucopyranan 0.37 of synthesized (1 → 6) -α-D-glucopyranan
15 g of dry pyridine and 2.4 g of 3,5-dimethylphenyl isocyanate were added to the resulting mixture, and the mixture was reacted at 100 ° C. for 24 hours. After the reaction, the mixture was poured into a large amount of methanol to recover the polymer. After dissolving the polymer in dimethylformamide and reprecipitating with methanol was repeated three times, vacuum drying was performed to obtain 0.85 g of a reaction product. The reaction was analyzed by infrared spectroscopy and found to be 1743 cm
^{At -1} and 1616 cm ^-1 , absorption of urethane bond derived from CＣO was confirmed, and at 1540 cm ^-1 , absorption of urethane bond derived from NH was confirmed. In addition, the reaction was run at 270 MHz-
Analysis was performed by ¹ H-NMR, and 6.3 ppm to 7.0.
peaks derived from aromatic protons in the range of 9 to 1 ppm.
A broad peak derived from NH was confirmed in the range of 0 ppm.

Preparation of Optical Resolving Agent and Optical Resolution The above carbamate-glucopyranan polymer 0.2 was added to 0.8 g of silica gel (Daiso gel SP-1000) hydrophobized with trimethylsilyl chloride.
g of dimethylformamide solution was coated. Then, after performing particle size separation, a slurry filling machine (Chemc
o, ECONO-PACKER CPP-085) using a stainless steel column (25 cm × 0.20).
cmI. D. ) Packing. This column was connected to a high performance liquid chromatograph, and the optical resolution of the racemic compound shown in Table 2 was performed at a flow rate of 0.5 ml / min using hexane / isopropyl alcohol (9: 1) as an eluent. It is shown in FIG.

The resolution α is an index indicating the resolution of the column, and was calculated according to the following equation (2).

(Equation 2) (Here, t ₁ and t ₂ are the retention times of the optical isomers, and t ₀ is the retention time of the substance passing through the column.)

Comparative Example 1 Dextran (weight average molecular weight: 40,000, molecular weight distribution: 1.6), which is a natural glucopyranan polymer, was carbamate-formed in the same manner as in Example 5. As in Example 5, the column was connected to a high performance liquid chromatograph to perform optical resolution of the racemic compound shown in Table 2,
Hexane / isopropyl alcohol (9:
Using 1) at a flow rate of 0.5 ml / min, the results are shown in Table 2.

1 to 5, R ₅ represents an allyl group;
R ₆ represents a propenyl group, and the polymerization degree n is an integer of 20 or more, preferably 25 or more, more preferably 28 or more, and particularly preferably 30 or more.

[0025]

[Table 2]

[0026]

The glucopyranan polymer of the present invention can easily provide a glucopyranan polymer having a narrow molecular weight distribution and usable for the synthesis of an optical resolving agent by using a specific polymerization initiator. Furthermore, the optical resolving agent obtained from the glucopyranan polymer can provide an optical resolving agent having high asymmetric discrimination ability.

[Brief description of the drawings]

FIG. 1 is a measurement spectrum of 300 MHz- ¹ H-NMR (solvent: deuterated chloroform).

FIG. 2 shows a measurement spectrum of 75 MHz- ¹³ C-NMR (solvent: deuterated chloroform).

FIG. 3 shows a measurement spectrum of 300 MHz- ¹ H-NMR (solvent: deuterated chloroform).

FIG. 4 300 MHz- ¹ H-NMR (solvent: heavy water,
Measurement temperature: 40 ° C).

FIG. 5 shows a measurement spectrum of 75 MHz- ¹³ C-NMR (solvent: heavy water, measurement temperature: 40 ° C.).

Continued on the front page (72) Inventor Hiromitsu Kanai 8-1 Goi South Coast, Ichihara City, Chiba Prefecture Ube Industries, Ltd. Polymer Research Laboratory F-term (reference) 4C090 AA01 BB12 BB38 BB52 BD37 CA35 DA40

Claims (2)

[Claims] 1. A glucopyranan polymer represented by the general formula (2) obtained by polymerizing a levoglucosan compound represented by the general formula (1), wherein a fluorinated alkylsulfonic acid is used as a polymerization initiator, and a molecular weight of the glucopyranan polymer is obtained. A glucopyranan polymer having a distribution (Mw / Mn) of 1.5 or less. Embedded image (Here, R ₁ , R _2, and R ₃ represent an alkyl group, a benzyl group, or an allyl group, and may be the same or different groups.) (Here, R ₁ , R _2, and R ₃ represent an alkyl group, a benzyl group, or an allyl group, and may be the same or different groups. N represents an integer of 20 or more.) 2. The glucopyranan polymer according to claim 1, wherein the levoglucosan compound is 2,3,4-tri-O-allyl-levoglucosan.