JPH1030007A - Polymer of n-(meth)acryloyl-beta-hydroxy-aspartic acid or its alkyl ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject polymer having various properties such as liquid- crystalline nature, bio-compatibility and polymer electrolyte property by using a monomer consisting of a new compound having β-hydroxyaspartic acid and its alkyl ester on the side chain. SOLUTION: This polymer is composed of the recurring unit of the formula I (R<1> is H or methyl; R<2> is H or a 1-5C alkyl). The β-hydroxyaspartic acid in the polymer preferably has L-threo structure. The polymer has a molecular weight of preferably 5,000-1,000,000. The polymer can be produced by polymerizing N-(meth)acryloyl-β-hydroxyaspartic acid of the formula II or its alkyl ester in the presence of a polymerization initiator. The compound of the formula II is a new compound producible by reacting β-hydroxyaspartic acid or its alkyl ester with (meth)acryloyl chloride.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel compound, N
The present invention relates to (meth) acryloyl-β-hydroxy-aspartic acid and an alkyl ester thereof, a production method thereof, and a polymer of the compound.

[0002]

2. Description of the Related Art Various vinyl monomers having an α-amino acid structure in the side chain are known, and they are interested in polymerization behavior based on the chirality of the side chain and the structure and properties of the resulting polymer. However, there has been no report on the synthesis of (meth) -acrylamide having β-hydroxy-aspartic acid and its alkyl ester in the side chain and this polymer.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel polymer expected to have properties such as liquid crystallinity, biocompatibility, biodegradability, and polymer electrolyte. Another object of the present invention is to provide a monomer compound as a starting material of such a novel polymer and a method for producing the same.

[0004]

Means for Solving the Problems The present inventors have a unique steric structure and biological activity derived from β-hydroxy-aspartic acid and its alkyl ester structure,
As a result of intensive studies to obtain a novel polymer exhibiting properties such as liquid crystallinity, biocompatibility, and biodegradability, β-hydroxy-aspartic acid and its alkyl ester structure are introduced into the side chain of poly (meth) acrylamide. Inspired
The present invention has been completed.

That is, the present invention provides the following formula (3)

[0006]

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[Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. And a polymer of N- (meth) -acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof, or a salt thereof. Furthermore, the present invention provides the following formula (2)

[0008]

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Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. N- (meth) -acryloyl-
Formula (3) obtained by a polymerization reaction in the presence of a polymerization initiator of β-hydroxy-aspartic acid or its alkyl ester

[0010]

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[In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. And a method for producing a polymer of N- (meth) -acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof, or a salt thereof. Furthermore, the present invention provides the following formula (2)

[0012]

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[In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. N- (meth) -acryloyl-
It relates to β-hydroxy-aspartic acid or an alkyl ester thereof. Further, the present invention provides a method of formula (1)

[0014]

Embedded image [In the formula, R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Formula (2) obtained by reacting (meth) acryloyl chloride with β-hydroxy-aspartic acid or an alkyl ester thereof represented by the following formula:

[0015]

Embedded image [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ] -N- (meth) -acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof. Further, the present invention provides the following formulas (3) and (4)

[0016]

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[In the formula, R ¹ is the same or independently a hydrogen atom or a methyl group, and R ² is the same or independent hydrogen atom or an alkyl group having 1 to 5 carbon atoms. And a salt thereof. Further, the following equation (2)

[0018]

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[In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. N- (meth) acryloyl-β-
Hydroxy-aspartic acid or its alkyl ester and the following formula (5)

[0020]

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[In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ] The method for producing a copolymer as described above, which is obtained by a polymerization reaction of an alkyl- (meth) -acrylate represented by the formula (1) in the presence of a polymerization initiator. And the following equation (3)

[0022]

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[In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Wherein the amide bond of the polymer of N- (meth) acryloyl-c-β-hydroxy-aspartic acid or an alkyl ester thereof is partially hydrolyzed or further esterified. The present invention relates to a method for producing a copolymer of Further, the present invention provides a compound represented by the following formula (3) derived from N- (meth) acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof.

[0024]

Embedded image [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ] Is contained as a component of the polymer.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, (meth) acryloyl means an acryloyl group (CH ₂ CHCO—) or a methacryloyl group (CH ₂ ＣC (CH ₃ ) CO—). In the present invention, R ¹ represents a hydrogen atom or a methyl group, preferably a methyl group. R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms,
Specific examples of the alkyl group include a methyl group, an ethyl group and n-
A propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, a 2-methylbutyl group and a 2,2-dimethylpropyl group, preferably a methyl group and an ethyl group It is. In the compounds of the formulas (2) and (3), R ¹ is preferably a hydrogen atom, R ² is a methyl group,
Ethyl group compounds are preferred.

In the polymer of the compound of the present invention, the structural site of β-hydroxy-aspartic acid may be L-threo or D-threo, or L-erythro- -It may be an erythro body. A mixture of these may be used, but from the viewpoint of liquid crystallinity, any one of them is preferable, and from the viewpoint of biocompatibility, the L-form is preferable. When R ² is a hydrogen atom in the polymer of the present invention, a salt with a base is formed, for example, a salt with an inorganic base such as sodium, potassium or calcium, and a salt with an organic base such as triethylamine. . Preferably, salts with sodium and potassium are preferred.

The process for producing the polymer of the present invention will be described below. A. Compound of formula (2): N- (meth) acryloyl-β
Method for producing hydroxy-aspartic acid or alkyl ester thereof N- (meth) acryloyl-β-hydroxy-
Aspartic acid or an alkyl ester thereof is obtained by subjecting β-hydroxy-aspartic acid or an alkyl ester thereof (the compound of the formula 1) and (meth) -acryloyl acid or a derivative thereof to an active esterification method, a mixed anhydride method,
Azide method, acid chloride method, symmetric acid anhydride method, DCC method, D
It can be obtained by an amide bond synthesis method such as the CC-additive method and the carbonylimidazole method. In particular, β-hydroxy-aspartic acid or its alkyl ester (formula 1
The compound (c) is reacted with (meth) acryloyl chloride to form an acid chloride.

The starting β-hydroxy-aspartic acid alkyl ester is a mixture of β-hydroxy-aspartic acid and an alcohol (R ² OH, where R ² has 1 carbon atom).
To 5 to 5) by a known method. β-hydroxy-aspartic acid may be L-form or D-form, or a mixture thereof. Alcohols include methanol, ethanol, propanol, isopropanol,
N-butanol, t-butanol and the like are used, and methanol and ethanol are particularly preferable. The β-hydroxy-aspartic acid alkyl ester obtained by such a reaction usually exists in the form of a hydrochloride or p-toluenesulfonate. In the present invention, β-hydroxy-aspartic acid alkyl ester may be used in the form of these salts, or desalted and isolated β-hydroxy-aspartic acid may be used.
Hydroxy-aspartic acid alkyl esters can also be used.

By reacting β-hydroxy-aspartic acid or its alkyl ester with (meth) acryloyl chloride, N- (meth) acryloyl-β-hydroxy-aspartic acid or its alkyl ester according to the present invention can be obtained. This reaction is carried out using a halogenated hydrocarbon solvent such as methylene chloride and chloroform;
The reaction is carried out in a solvent such as an aprotic polar solvent such as F, acetonitrile and DMF at about -20 ° C to -50 ° C for about 1 to 24 hours. During the reaction, triethylamine, t
-BuOk, K ₂ CO _3, it is desirable to add a base such as Na ₂ CO _3. N- (meth) acryloyl-β-
When obtaining hydroxy-aspartic acid, this reaction is carried out in water or a polar solvent such as acetonitrile containing water, DMF, alcohol or the like at 0 ° C. or lower for about 1 to 10 hours.
Also, triethylamine, NaOH, KOH, Na ₂ CO
₃ , It is desirable to add a base such as K ₂ CO ₃ . Such N- (meth) acryloyl-β- according to the present invention.
The structures of hydroxy-aspartic acid and its alkyl ester can be determined by nuclear magnetic resonance analysis (NMR), infrared absorption analysis (IR), mass spectrometry (MS), and the like.

B. Method for producing polymer of compound of formula (3): N- (meth) acryloyl-β-hydroxyaspartic acid or alkyl ester thereof N- (meth) acryloyl-β-hydroxyaspartic acid polymer according to the present invention and alkyl thereof The ester polymer is obtained by polymerizing the above N- (meth) acryloyl-β-hydroxyaspartic acid or its alkyl ester (compound of the formula 2) in the presence of a polymerization initiator. As the polymerization initiator, conventionally known radical polymerization agents such as azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), acetyl peroxide, and persulfate are preferably used. The polymerization reaction is a solid phase (bulk polymerization)
The polymerization may be carried out in a liquid phase using chlorobenzene, dimethylformamide, methanol, water or the like as a reaction solvent.

It is desirable that the polymerization initiator is used in an amount of about 0.1 to 10 mol% based on 1 mol of all monomers. In the case of liquid phase polymerization, the monomer concentration in the reaction system is usually preferably about 0.1 to 10 mol / l. The polymerization temperature is appropriately set according to the type of the polymerization initiator. The polymerization time is usually about 1 to 72 hours. After the reaction for a predetermined time, the polymerization is stopped, and the polymer is washed and dried to obtain an N- (meth) acryloyl-β-hydroxy-aspartic acid polymer or an alkyl ester polymer thereof. The molecular weight of the obtained N- (meth) acryloyl-β-hydroxy-aspartic acid polymer or its alkyl ester polymer is usually from 5,000 to
About 1,000,000, preferably 10,000
It is about 0 to 500,000. In addition, N- (meth) acryloyl-β-hydroxy-aspartic acid polymer is an N- (meth) acryloyl-β-hydroxy-aspartic acid alkyl ester polymer which is an acid of HCI, H ₂ SO ₄ or an acid such as HaOH, KOH. It can also be obtained by hydrolysis using a base.

Next, the copolymer of the present invention in which the repeating units represented by the formulas (3) and (4) are randomly polymerized is N- (meth) acryloyl-β-hydroxy-aspartic acid or its alkyl ester ( (Compound of formula 2) and (meth) -acrylic acid or an alkyl ester thereof (compound of formula 5)
N- (meth) acryloyl-β-hydroxy-
The reaction is carried out under the same conditions as in the homopolymerization of aspartic acid or its alkyl ester.

N- (meth) in the copolymer of the present invention
A structural unit (formula 3) derived from -acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof (compound of formula 2) and a structural unit derived from (meth) -acrylic acid or an alkyl ester thereof (compound of formula 5) The ratio with the structural unit (Formula 4) can be variously achieved by changing the reaction molar ratio of the compound of Formula 2 and the compound of Formula 5.
Although not particularly limited in the present application, the ratio (molar ratio) of the structural unit (formula 3) and the structural unit (formula 4) is usually 99/1 to 1/1.
99 preferably about 95/5 to 5/95. Also,
Various kinds of polymers comprising the structural unit (Formula 3) and the structural unit (Formula 4) of the present invention are variously and randomly polymerized. Further, the above copolymer can be obtained by partial hydrolysis of a homopolymer of N- (meth) -acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof with an acid, and the obtained hydrolyzate is easily obtained. To an alkyl ester. As the alkyl ester, for example, a method using diazomethane, diazoethane, or diazopropane and the above-described alcohol / acid method are used.

Next, a unit represented by the formula (3) derived from N- (meth) acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof according to the present invention is contained as one component of a polymer. The resulting polymer can be polymerized under the conditions described above together with N- (meth) acryloyl-β-hydroxy-aspartic acid or its alkyl ester alone or with other polymer monomers. Other polymerizable monomers include (meth) acrylic acid, acrylonitrile, acrylamide,
Styrene, butadiene and the like can be mentioned.

The polymer thus obtained has a plastic shape and can be used as a shaping material such as a film. Test Example 1 200 mg of the polymer obtained in Example 4 was dissolved in about 1 ml of chloroform methanol (3: 1), and the solution was spread on a Teflon plate and air-dried overnight to obtain a diameter of about 2.5 cm.
Of a colorless film was obtained.

Further, the polymer according to the present invention has the characteristics of a polymer electrolyte. The characteristics of the polymer electrolyte are, for example, those that can be used for electrodeposition coating. Test Example 2 N-methacryloyl-L-threo- obtained in Example 6
0.1 M of β-hydroxy-aspartic acid polymer
The respective intrinsic viscosities ηinh of the aqueous NaClO ₄ solution were measured at 25 ° C. (C 0.11) using an Ostwald viscometer. Table 1 shows the results.

[0037]

[Table 1] The polymer of the present invention has a unique steric structure derived from β-hydroxy-aspartic acid or its alkyl ester structure,
It is expected to exhibit properties such as liquid crystallinity, biocompatibility, biodegradability, and polymer electrolyte in combination with physiological activities. In particular, the polymer of the present invention is excellent in water solubility, biocompatibility,
It is expected to exhibit biodegradability and properties to polymer electrolytes.

[0038]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Example 1 [N-methacryloyl-L-threo-β-hydroxy-
Synthesis of dimethyl aspartate] L-threo-
β-Hydroxy-aspartic acid dimethyl ester hydrochloride (2.1 g, 10 mmol) was added to DMF (40 ml).
Was dissolved. The resulting solution was kept at -47 ° C, and triethylamine (25 mmol) was added.
At ℃, methacryloyl chloride (10 mmol) was added dropwise. After continuing the reaction for 2 hours, the reaction mixture was cooled with ice water (12
0 ml) and extracted twice with ethyl acetate (100 ml). The ethyl acetate solution was washed with saturated NaHCO ₃ and then with saturated aqueous NaCl. The obtained ethyl acetate solution is
The mixture was treated with a ₂ SO ₄ and dried under reduced pressure to obtain a crude product. This was separated by silica gel chromatography using n-hexane and ethyl acetate (2: 1) as a developing solvent to obtain N-methacryloyl-L-threo-β-hydroxy-aspartic acid dimethyl ester in a yield of 57%. Was.

The specific luminous intensity, FAB-MS analysis result, IR spectrum data, and NMR spectrum data of the obtained dimethyl N-methacryloyl-L-threo-β-hydroxy-aspartate are shown below. [Α] ²⁰ _D : + 13.0 ° (C 1.0, DMF) FAB-MS: 246 (M + 1) ⁺ IR (film): 3378, 2957, 1747, 1
666, 1624, 1518, 1438, 1351, 1
^{274,1209,1104,985,937cm -1 1 HNMR (300MHz, D} 6 -DMSO) δ (ppm): 6.58 (1H, d, J = 9Hz),
5.75 (1H, s) 5.40 (1H, s), 5.17 (1H, d, J = 9H)
z) 4.76 (1H, s), 3.82 (6H, s), 3.5
1 (1H, s), 1.96 (3H, s) ¹³ C NMR (75 MHz, D ₆ -DMSO) δ (ppm): 172.4, 169.7, 168.
4,139.2,120.7,70.9,54.6,5
3.4, 53.1, 18.5

Example 2 [N-methacryloyl-L-threo-β-hydroxy-
Polymerization of dimethyl aspartate] To 3 mmol of N-methacryloyl-L-threo-β-hydroxy-aspartate dimethyl ester obtained in Example 1 was added 2,2'-azobisisobutyronitrile (AIB).
N) was added at 1 mol%, and the tube was degassed and sealed, and solid phase polymerization was performed at 60 ° C. for 20 hours. After a lapse of 20 hours, the obtained polymer was washed with diethyl ether and dried under reduced pressure to recover the polymer in a yield of 29%. The molecular weight and molecular weight distribution of the obtained polymer were determined from polystyrene conversion by GPC. In addition, the glass transition temperature (T
g) was measured by DSC. Td ₁₀ (10
% Weight loss temperature) was determined by thermogravimetric analysis in a stream of nitrogen. The specific light intensity [α] _D was measured at 20 ° C. (C1.0, DMF). Table 2 shows the results.

Examples 3, 4 and 5 3 mmol of N-methacryloyl-L-threo-β-hydroxy-aspartic acid dimethyl ester were used as polymerization solvents for methanol (Example 3), dimethylformamide (Example 4) and chlorobenzene. The same operation as in Example 2 was performed except that the solution was dissolved in (Example 5) to a concentration of 1 mol / liter and liquid phase polymerization was performed. Table 2 shows the results
Shown in

[0042]

TABLE 1 Polymerization solvent ratio (%) Molecular weight (Mn) Molecular weight distribution (Mw / Mn) Example 2 None 29 484,000 7.31 Example 3 Methanol 81 42,000 1.99 Example 4 Dimethylformamide 84 38,900 2.37 Example 5 dichlorobenzene 93 71,300 3.06 Tg (° C.) Td ₁₀ (° C.) [α] _D (°) Example 2 124.1 270.5 +1.2 Example 3 107.7 270.8 +0.5 Example 4 120.5 271.7 -0.8 Example 5 122.0 270.5 -0.1

Example 6 2 ml of 2.5N NaOH was added to 122 mg of a polymer of dimethyl N-methacryloyl-L-threo-β-hydroxy-aspartate and stirred at about 15 ° C. for 24 hours. The reaction solution was Dowex 50W (H ⁺ ) 10m
The resulting aqueous solution was lyophilized to give 98 mg (90.7%) of a polymer of N-methacryloyl-L-threo-β-hydroxy-aspartic acid. The same analysis operation as in Example 2 was performed except that the light measurement was performed in water. Average molecular weight: 47000, molecular weight distribution: 1.37 Td
₁₀ : 202.4 ° C. [α] ²⁰ _D + 30.5 ° (C 1.0, H ₂ O). When the dissociation constant is determined by alkali titration, pKa
1: 3.74, pKa2: 6.37.

Embodiment 7 FIG. [N-methacryloyl-L-threo-β-hydroxy-
Copolymerization of Aspartic Acid Dimethyl Ester (MHAM) and Methyl Methacrylate (MMA)] The MHAM and MMA obtained in Example 1 were supplied to the polymerization system in a molar ratio shown in Table 3 so as to be a total of 3 mmol. Example 4 except that dimethylformamide was used as a polymerization solvent.
The same operation as described above was performed. The specific luminous intensity [α] _D was measured at 20 ° C. (C 1.0, chloroform). In this example, the composition of the photopolymer was determined by ¹ H-NMR spectrum. Table 3 shows the results.

[0045]

[Table 3]

Example 8 [N-methacryloyl-L-threo-β-hydroxy-
Hydrolysis of dimethyl aspartate polymer and synthesis of MHAM / MMA copolymer by ester] Polymer of N-methacryloyl-L-threo-β-hydroxy-aspartic acid 1.4 obtained according to Example 6
g in 100 ml of 6N HCl.
When stirring was continued for 96 hours, 600 mg of a solid corresponding to a copolymer of N-methacryloyl-L-threo-β-hydroxy-aspartic acid and methacrylic acid was obtained. When 0.1 g of this copolymer is treated with diazomethane, MHAM
0.11 g of a powder corresponding to a copolymer of and MMA was obtained. Molecular weight (Mn) 63,500 Molecular weight distribution (Mw / Mn) 2.50 Specific rotation [α] ²⁰ _D -8.1 ° [C 1.0, chloroform]

Example 9 [N-methacryloyl-L-threo-β-hydroxy-
Synthesis of aspartic acid] L-threo-β-hydroxy-
5N of aspartic acid (7.45 g, 50 mmol)
Methacryloyl chloride (50 mmol) and 5N NaOH (10 ml) were added dropwise to an aqueous solution of NaOH (20 ml) with stirring at 0 to 2 ° C over a period of 40 minutes. After continuing stirring for 3 hours while maintaining the reaction mixture at 0 to 2 ° C, the reaction solution is acidified with concentrated hydrochloric acid (pH 1.0 to 1.
5). After extracting twice with ether (20 ml), the aqueous layer was extracted several times with ethyl acetate (50 ml). The ethyl acetate layers were combined, treated with MgSO ₄ , and dried under reduced pressure to obtain 5.9 g (yield 54%) of N-methacryloyl-L-threo-β-hydroxy-aspartic acid. Specific rotation of this substance, FAB-MS analysis result, IR
The spectrum data and NMR spectrum data are shown below.

[Α] ²⁰ _D : + 20.2 ° (C 1.0, H ₂ O) FAB-MS: 218 (M + 1) ⁺ IR (KBr): 3390, 2987, 1740, 1
655,1616,1528,1379,1210,1
^{100,939cm -1 1 HNMR (300MHz, D} 6 -DMSO) δ (ppm): 7.58 (1H, d, J = 9.4),
5.69 (1H, s) 5.43 (1H, s), 4.79 (1H, dd, J =
2.9, 9.4), 4.53 (1H, d, J = 2.
9), 1.85 (3H, s) ¹³ C NMR (75 MHz, D ₆ -DMSO) δ (ppm): 172.6, 170.9, 167.
7, 139.4, 120.1, 70.7, 55.3, 1
8.5

Example 10 [N-methacryloyl-L-threo-β-hydroxy-
Polymerization of aspartic acid] N-methacryl-L-threo-β-hydroxy-aspartic acid (2.17 g, 10 mmol) obtained in Example 9 was added to 5N NaOH (9.
5 ml), water (0.5 ml) and sodium persulfate (0.1 mmol) were added, and liquid phase polymerization was carried out at 60 ° C. for 20 hours under a nitrogen stream. The reaction solution was Dowex 50W
(H ⁺⁾ and Dowex WGR (OH ^-) was lyophilized after treated with. The obtained white powder was washed with ethyl acetate and dried to obtain a polymer (1.74 g, yield 80%) similar to that obtained in Example 6. [Α] ²⁰ _D : + 3.33 ° (C 1.0, H ₂ O)

[0050]

Industrial Applicability The polymer of the present invention exhibits a plastic shape, has a unique steric structure derived from β-hydroxy-aspartic acid or its alkyl ester structure, and a physiological activity, and exhibits liquid crystallinity, biocompatibility, and bioactivity. It is expected to exhibit properties such as degradability and polymer electrolyte.

Claims (12)

[Claims] (1) The following formula (3): [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. A polymer of N- (meth) -acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof, or a salt thereof, comprising a repeating unit represented by the following formula: 2. The polymer according to claim 1, wherein the structural site of β-hydroxyaspartic acid is L-threo, or a salt thereof. 3. A molecular weight of 5,000 to 1,000,000.
The polymer according to claim 1, which is in the range of or a salt thereof. 4. A compound represented by the following formula (2): [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. The polymer according to claim 1, which is obtained by polymerizing N- (meth) acryloyl-β-hydroxyaspartic acid or an alkyl ester thereof represented by the formula above in the presence of a polymerization initiator, or a salt thereof. 5. A compound represented by the following formula (2): [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Formula (3) obtained by a polymerization reaction of N- (meth) acryloyl-β-hydroxyaspartic acid or an alkyl ester thereof represented by the following formula in the presence of a polymerization initiator: [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. A method for producing a polymer of N- (meth) -acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof, or a salt thereof, comprising a repeating unit represented by the formula: 6. A compound represented by the following formula (2): [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. And N- (meth) acryloyl-β-hydroxyaspartic acid or an alkyl ester thereof. 7. The compound according to claim 6, wherein the structural site of β-hydroxyaspartic acid is an L-threo form. 8. A compound of the formula (1) [In the formula, R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Formula (2) obtained by reacting (meth) acryloyl chloride with β-hydroxy-aspartic acid or an alkyl ester thereof represented by the following formula: [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. The method for producing N- (meth) acryloyl-β-hydroxyaspartic acid or an alkyl ester thereof represented by the formula: 9. The following formulas (3) and (4): [Wherein, R ¹ is the same or independently a hydrogen atom or a methyl group, and R ² is the same or independent hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Or a salt thereof, wherein the repeating unit represented by the formula (1) is randomly polymerized. 10. The following formula (2): [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. N- (meth) acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof represented by the following formula (5): [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. The method for producing a copolymer according to claim 9, which is obtained by a polymerization reaction of an alkyl- (meth) -acrylate represented by the formula (1) in the presence of a polymerization initiator. 11. The following formula (3): [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. The amide bond of a polymer of N- (meth) -acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof comprising a repeating unit represented by the following formula: is partially hydrolyzed or further esterified. A method for producing a copolymer of 12. A compound of the following formula (3) derived from N- (meth) acryloyl-β-hydroxy-aspartic acid or an alkyl ester thereof. [Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ] As a constituent of the polymer.