KR20160123563A - Photo curable 4-functionalized isosorbide derivative compound and method for preparing the same - Google Patents

Abstract

The present invention relates to a photocurable 4-functionalized isosorbide derivative compound, and relates to a manufacturing method thereof. The photocurable 4-functionalized isosorbide derivative compound of the present invention removes a hydroxyl group by substituting an acrylate group instead of the hydroxyl group, thereby applying the same to a dental material. In addition, the photocurable 4-functionalized isosorbide derivative compound can reduce a shrinkage rate and a moisture-absorbing rate, which can be the causes to decline aesthetic properties and mechanical properties of a dental filling material, and has effects in improving the mechanical properties such as the compression strength, the bending strength, and the like.

Description

[0001] PHOTO CURABLE 4-FUNCTIONALIZED ISOSORBIDE DERIVATIVE COMPOUND AND METHOD FOR PREPARING THE SAME [0002]

The present invention relates to a photocurable 4-functional isosorbide derivative compound and a process for producing the same, and more particularly, to a photocurable 4-functional isosorbide derivative compound containing four acrylate groups and not containing a hydroxyl group, And a method for producing the same.

Curable materials such as adhesives, adhesives, sealants, coatings and paints are currently being used in various industrial fields such as packaging, bookbinding, automotive, electronics, precision, optical products, woodworking, plywood, It is widely used for home use, and its use has become widespread, and recently it has also been applied to concrete. Such adhesives and the like are manufactured in the form of a mixture of chemical materials based on a synthetic resin. Since the volatile organic compounds (VOC) are added due to the organic solvent (solvent) used in the manufacturing process and various volatile additives added to improve the physical properties, , Dioxins, and environmental hormones. Recently, the production and use of these harmful substances have been strictly restricted through environmental regulations under international treaties. Furthermore, the EU has used these regulations as a means of new trade sanctions. In keeping with this trend, conventional solvent type adhesives have been replaced by water-soluble, solvent-free, hot-melt type and the like. Furthermore, not only these adhesive materials, but most of the fine chemical materials we currently use are petrochemical products derived from the Oil Refinery Process. However, international oil prices are steadily rising due to a decrease in reserves and a surge in demand centering on BRICs. As international conventions that strictly regulate greenhouse gas emissions become effective, future use of irreversible fossil resources such as oil will lead to enormous environmental costs . Therefore, many efforts have been made to obtain existing petroleum-derived fine chemical products from new resources, and the most representative example is to use carbohydrate-based biomass as a supply source. The natural world produces about 170 billion tons of carbohydrates every year through photosynthesis. Human beings use only about 3% of them as food, paper, furniture, and building materials. Thus, fine chemicals manufactured from renewable and sustainable carbohydrate biomass are expected to replace petrochemicals. Accordingly, in order to replace conventional light source curing adhesive materials derived from petroleum resources, development of a technology for synthesizing compounds having predetermined adhesion or adhesion properties using such environmentally friendly carbohydrate-based biomass is required. As a representative example of the carbohydrate-based biomass, there is an isosorbide derivative.

Isosorbide is a heterocyclic compound derived from glucose, which can be obtained by hydrogenating glucose to form sorbitol, which can be double dehydrated. The isosorbide has a V-shaped structure in which two tetrahydrofuran rings are bonded at an angle of 120 ° and has a hydroxyl group at carbon positions 2 and 6. Isosorbide is a compound of a solid structure having optical asymmetry, and derivatives thereof are useful as raw materials for pharmaceutical raw materials and high-functional industrial materials because they exhibit specific functions. In addition, isosorbide is excellent in optical properties and thermal properties and is used in optical electronic components such as optical disk substrates, optical fibers, and lenses. In addition, the composition of the present invention can be utilized as a composition of a dental filler by applying an isosorbide derivative. Bis (4- (2-hydroxy-3-methacryloyloxypropoxy) phenyl) propane (Bis-GMA) which is the bisphenol system most commonly used as a prepolymer of a dental material composition . This is mainly used for matrix resin because it has advantages such as low volatility and polymerization shrinkage and good strength of polymeric compound using it. However, bisphenol compound plays a role like estrogen in the human body and can cause endocrine disruption . In order to solve such a problem, there has been an effort to replace it with an isosorbide-based compound derived from biomass which is harmless to human body.

However, since such an isobide-based compound contains a hydroxy group in the compound, when used as a dental filler, etc., the mechanical strength is weakened due to the property of absorbing water, and the aesthetics are deteriorated due to shrinkage of the material itself.

Korean Patent Laid-Open No. 10-2012-0129253

Korean Patent Publication No. 10-2013-0130350

Disclosure of the Invention The object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to minimize the damage due to contact of water by replacing an acrylate group in place of a hydroxyl group (-OH) bonded to an isosorbide compound To provide a photocurable 4-functional isosorbide derivative compound having improved mechanical strength and reduced shrinkage, and a process for producing the same.

According to one aspect of the present invention, there is provided a compound represented by the following structural formula (1).

[Structural formula 1]

In formula 1,

m And n may be the same or different from each other, and each independently is an integer of 1 to 3,

R ¹ is each independently any one of a hydrogen atom, a methyl group and an ethyl group,

R ² each independently represents a hydrogen atom, a methyl group or an ethyl group.

Preferably, each R ¹ is independently a hydrogen atom or a methyl group, and each R ² may independently be a hydrogen atom or a methyl group.

Preferably, m And n can be 1.

The compound represented by Formula 1 may be a compound represented by Formula 1 below.

[Chemical Formula 1]

According to another aspect of the present invention, there is provided a process for preparing a compound represented by the following Formula 1 by reacting a compound represented by the following Formula 2 with a compound represented by the following Formula 3 (Step a);

≪ / RTI > is provided.

[Structural formula 1]

In formula 1,

m And n may be the same or different from each other, and each independently is an integer of 1 to 3,

R ¹ is each independently any one of a hydrogen atom, a methyl group and an ethyl group,

R ² each independently represents a hydrogen atom, a methyl group or an ethyl group.

[Structural formula 2]

In formula 2,

m And n may be the same or different from each other, and each independently is an integer of 1 to 3,

Each R ¹ is independently a hydrogen atom, a methyl group or an ethyl group.

[Structural Formula 3]

In Structure 3,

R ² each independently represents a hydrogen atom, a methyl group or an ethyl group,

및

중 어느 하나이고,X is Cl, Br, I,

And

, ≪ / RTI >

R ³ is any one of a hydrogen atom, a methyl group and an ethyl group,

R < ⁴ > is a C1 to C4 linear or branched alkyl group.

(A-1) preparing a compound represented by the formula 2 and the compound represented by the formula 3, respectively; Reacting a compound represented by the formula 2 and a compound represented by the formula 3 to prepare a compound represented by the formula 1 (step a-2); And purifying the product of step a-2 (step a-3); . ≪ / RTI >

The reaction may be carried out at 20 to 100 < 0 > C.

The reaction may be carried out for 12 to 48 hours.

The purification may be carried out by extraction or column chromatography.

The extraction may be carried out using at least one selected from methylene chloride, ethyl acetate, diethyl ether, toluene, and hexane.

According to another aspect of the present invention, there is provided a material comprising the compound represented by the structural formula (1).

There is provided a dental filling material comprising the above material.

The dental filling material may further comprise a compound represented by the following formula (4).

[Chemical Formula 4]

The dental filling material may contain 1 to 30 parts by weight of the compound represented by the structural formula 1 based on 100 parts by weight of the compound represented by the formula 4.

The present invention can be applied to a dental material by replacing a methacrylate group in place of a hydroxy group with a photocurable 4-functional isosorbide derivative compound to remove a hydroxy group. In addition, it is possible to reduce the shrinkage rate and water absorption rate, which cause mechanical property and aesthetic deterioration of the dental filler, and improve the mechanical properties such as compressive strength and flexural strength.

FIG. 1 shows nuclear magnetic resonance (NMR) analysis results of the compound prepared according to Example 1. FIG.
2 is a graph showing the result of analysis of the compressive strength according to Test Example 1. Fig.
3 is a graph showing the results of analysis of flexural strength according to Test Example 2. Fig.
4 is a graph showing the results of analysis of resin shrinkage percentage according to Test Example 3. Fig.
5 is a graph showing the results of analysis of water absorption according to Test Example 4. Fig.

The invention is capable of various modifications and may have various embodiments, and particular embodiments are exemplified and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Furthermore, terms including an ordinal number such as first, second, etc. to be used below can be used to describe various elements, but the constituent elements are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

Also, when an element is referred to as being "formed" or "laminated" on another element, it may be formed or laminated directly on the front surface or one surface of the other element, It will be appreciated that other components may be present in the < / RTI >

The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, the photocurable 4-functional isosorbide derivative of the present invention will be described.

The photocurable 4-functional isosorbide derivative of the present invention may be a compound represented by the following structural formula (1).

[Structural formula 1]

In formula 1,

m And n may be the same or different from each other, and each independently is an integer of 1 to 3,

R ¹ is each independently any one of a hydrogen atom, a methyl group and an ethyl group,

R ² each independently represents a hydrogen atom, a methyl group or an ethyl group.

In the above structural formula 1, preferably, each R ¹ is independently a hydrogen atom or a methyl group, each of R ² may independently be a hydrogen atom or a methyl group, more preferably R ¹ may be a methyl group, and R ² may be a methyl group .

In the above structural formula 1, m And n may be 1.

The compound represented by Formula 1 may be a compound represented by Formula 1 below.

[Chemical Formula 1]

Hereinafter, a method of producing the photocurable 4-functional isosorbide derivative of the present invention will be described.

First, a compound represented by the following structural formula 2 is reacted with a compound represented by the following structural formula 3 to prepare a compound represented by the following structural formula 1 (step a).

[Structural formula 1]

In formula 1,

m And n may be the same or different from each other, and each independently is an integer of 1 to 3,

R ¹ is each independently any one of a hydrogen atom, a methyl group and an ethyl group,

R ² each independently represents a hydrogen atom, a methyl group or an ethyl group.

[Structural formula 2]

In formula 2,

m And n may be the same or different from each other, and each independently is an integer of 1 to 3,

Each R ¹ is independently a hydrogen atom, a methyl group or an ethyl group.

m And n may preferably be each independently 1 to 2, more preferably 1.

Preferably, R ¹ may be a hydrogen atom and a methyl group, more preferably a methyl group.

In the case of using 2- (3-bromopropyl) oxirane or C ₅ H ₉ BrO in the preparation of the compound represented by the structural formula 2, m and n (2-bromoethyl) oxirane, C ₄ H ₇ BrO) is used as the compound of formula (2), m And n is 2, and when epiboromhydrin (C ₃ H ₅ BrO) is used, a compound represented by the formula 2 And a compound wherein n is 1 can be prepared.

[Structural Formula 3]

In Structure 3,

R ² each independently represents a hydrogen atom, a methyl group or an ethyl group,

및

중 어느 하나이고,X is Cl, Br, I,

And

, ≪ / RTI >

R ³ is any one of a hydrogen atom, a methyl group and an ethyl group,

R < ⁴ > is a C1 to C4 linear or branched alkyl group.

Step a can be performed in three steps as specifically described below.

First, the compounds represented by the structural formulas 2 and 3 are prepared (step a-1).

A compound in a mixed state is prepared by adding a polymerization inhibitor, a base compound, and a solvent to each of the compounds represented by Structural Formulas 2 and 3, or a base compound or a compound represented by Structural Formula 3 is used as a solvent and reaction product , And a compound in a mixed state can be prepared by adding a polymerization inhibitor.

The polymerization inhibitor may be hydroquinone, methyl hydroquinone, monomethyl ether hydroquinone or the like, and preferably hydroquinone may be used.

The base compound may be a tertiary amine compound such as pyridine, trimethylamine, diisopropylethylamine, etc., preferably pyridine.

The solvent may be a chlorinated hydrocarbon compound such as methylene chloride, chloroform, 1,2-dichloroethane and the like, preferably methylene chloride.

Next, the compounds represented by the structural formula 2 and the structural formula 3 are reacted to prepare the compound represented by the structural formula 1 (step a-2).

The reaction may be carried out at a temperature of 20 to 100 캜, preferably 30 to 80 캜, more preferably 40 to 60 캜.

The reaction may be carried out for 12 to 48 hours, preferably 15 to 40 hours, more preferably 20 to 30 hours.

Finally, the product of step a-2 is purified (step a-3).

The purification may be carried out by extraction or column chromatography. Preferably, the compounds can be separated using extraction. Since the impurities may remain in the compound separated by the extraction or column chromatography, the impurities may be further removed by using column chromatography to increase the purity of the compound.

The solvent used in the extraction may be methylene chloride, ethyl acetate, diethyl ether, toluene, hexane and the like, preferably methylene chloride, ethyl Acetate, etc., but the scope of the present invention is not limited thereto.

A polymerization inhibitor may be added to the compound obtained by refining and stored. Preferably, hydroquinone, methylhydroquinone, monomethylether hydroquinone or the like may be added, and more preferably hydroquinone may be added.

The present invention provides a photocurable 4-functional isosorbide derivative compound represented by the structural formula 1 above.

There is provided a material comprising the photo-curable 4-functional isosorbide derivative compound represented by the structural formula 1 above.

A dental filling material containing the above materials can be produced.

The dental filling material may further comprise a compound represented by the following formula (4).

[Chemical Formula 4]

The dental filling material may contain 1 to 30, preferably 3 to 20, more preferably 5 to 15 parts by weight of the compound represented by the structural formula 1 with respect to 100 parts by weight of the compound represented by the formula 4 .

 Since the dental filling material contains the compound represented by the structural formula 1 in which the hydroxyl group (-OH) is removed, the moisture absorption of the dental filling material is lower than that of the dental filling material applied only with the compound represented by the chemical formula 4, Can be relatively long lasting.

[Example]

Manufacturing example  One

(Step 1)

Isosorbide (1-1) (1.0 g, 6.8 mmol) and KOH (2.8 g, 42 mmol) were placed in a 50 mL round-bottomed flask and covered with rubber stopper. Dry DMSO (5 mL) was then added under N ₂ atmosphere . A round bottom flask containing the reaction solution was immersed in a 40 ° C bath and thermally equilibrated. When thermal equilibrium was established inside the flask, epibromohydrin (3.84g, 28mmol) was slowly added dropwise via syringe. At this time, it was observed that the color of the suspension inside the flask gradually changed to dark brown depending on the drop amount. After dropwise addition, the mixture was reacted by stirring at 40 DEG C for 2 hours. Thereafter, the reaction solution was filtered through a syringe filter to remove salts from the residue, the filtrate was diluted with an appropriate amount of methylene chloride, and then transferred to a separating funnel. The mixture was washed with distilled water and brine in this order, and the organic layer was washed with water (MgSO ₄ ), filtered, concentrated under reduced pressure, and purified by flash chromatography (hexane: ethyl acetate = 1: 1) to give an isospoid The resulting compound (1-2) was obtained (1.1 g, 4.3 mmole, 63%).

The reaction of Step 1 is as shown in Scheme 1 below.

[Reaction Scheme 1]

(Step 2)

(1 g, 3.8 mmol), diphenyl picrylhydrazyl (10 mg, 0.6 mmol), and methacrylic acid (1 g) were added to a 100 mL round bottom flask under a nitrogen atmosphere. methacrylic acid (7 mL, 78 mmol) were added and stirred. Thereafter, 3 drops of tetraethylamine (TEA) was added dropwise, and the mixture was stirred at 100 占 폚 for 4 hours. After completion of the reaction, a dark brown reaction solution was obtained. The reaction solution was transferred to a separatory funnel, washed 5 times with 20 wt% NaHCO ₃ aqueous solution and treated with water / ethyl acetate (water / EA). The organic layer of the treated product was distilled to remove the solvent, and a viscous colorless compound (IsoGMA) was prepared by flash chromatography of hexane: ethyl acetate (1: 2, v / v) (1.23 g, 2.9 mmole, 75%).

The reaction of Step 2 is shown in Reaction Scheme 2 shown below.

[Reaction Scheme 2]

Example  One

[Reaction Scheme 3]

1.0 g (1 eq) of the compound (IsoGMA) prepared according to Preparation Example 1 and hydroquinone (hydroquinone, 2,000 ppm, 0.0167 g) as a polymerization inhibitor were placed in a 50 ml round bottom flask. Methacrylic anhydride 1.48g (2eq) of C ₈ H ₁₀ O ₃ , MAAH and 0.18g (1eq) of pyridine capable of serving as a catalyst or solvent were added thereto, and the mixture was reacted at 50 ° C for 24 hours with stirring.

After the reaction was completed, excess H ₂ O was added and stirred at ambient temperature for 3 hours. Thereafter, an excessive amount of potassium carbonate was added until a precipitate of potassium carbonate (K ₂ CO ₃ ) was observed, and then potassium carbonate was filtered out by filtration. The filtered material was loaded with methylene chloride (MC) and 10 wt% aqueous potassium carbonate (K ₂ CO ₃ ) solution to separate the organic layer containing methylene chloride.

The separated organic layer was washed with methylene chloride using a rotary evaporator, and the resulting material was purified by column chromatography using hexane (ethyl acetate = 3: 1) to give a pure photo-curable 4-functional isosorbide derivative compound ≪ / RTI >

0.1 wt% (1,000 ppm) hydroquinone was added to the photocurable 4-functional isosorbide derivative compound as a polymerization inhibitor and stored.

¹ H NMR analysis of the photocurable 4-functional isosorbide derivative compound is shown in FIG. 1, and ¹ H NMR data thereof is as follows.

_{^{1 H NMR (CDCl 3, 300MHz}} ): δ 6.18-6.02 (d, 4H), 5.70-5.43 (m, 4H), 5.40-5.17 (m, 2H), 4.66-4.59 (t, 1H), 4.50-3.56 (m, 13H), 1.96-1.89 (s, 12H).

Example  2: Manufacture of dental filling material

0.33 g of the compound (IsoGMA-4) prepared in Example 1 and 3 g of the compound (IsoGMA) prepared in accordance with Preparation Example 1 were mixed (weight ratio (wt%) of IsoGMA-4: IsoGMA = 1: 9) The dental filling material was prepared by mixing three times for 3 minutes at 2000 rpm using a planetary vacuum mixer.

Comparative Example  One:  Manufacture of dental filling materials

(BisGMa: TEGDMA = 6: 4 weight ratio (wt%)) of 3 g of the compound represented by the following formula 2 (bisGMA) and 2 g of the compound represented by the following formula 3 (TEGDMA) 3 times for 3 minutes to prepare a dental filling material.

(2)

(3)

Comparative Example  2

A dental filling material was prepared in the same manner as in Production Example 1.

[Test Example]

Test Example 1: Compressive Strength Analysis

Fig. 2 shows the measurement results of the material produced according to Example 2 and Comparative Examples 1, 2 and 3. Fig. Specimens for compressive strength were prepared by filling a cylindrical (Φ x L = 4 x 6 mm) SUS mold with the prepared resin mixture and using a 3M ESPE Elipar ^TM S10 was irradiated with visible light for 40 seconds on the front and back surfaces using a spot cure apparatus. The manufactured compressive strength specimens were measured by Universal Test Machine (UTM) Shimadzu AGS-X, Lord Sell 5000 N, crosshead speed 1 mm / min according to the International Standard Test (ISO4049).

2, it was confirmed that the compressive strength of the composition prepared according to Example 2 was maintained at a level similar to the compressive strength of the material prepared according to Comparative Examples 1 and 2.

Test Example 2: Flexural Strength Analysis

Fig. 3 shows the measurement results of flexural strength of the material produced according to Example 2 and Comparative Examples 1 and 2. Fig.

The flexural strength specimens were filled with a resin mixture prepared in a rectangular parallelepiped (H x W x L = 2 x 2 x 25 mm) SUS mold and extruded using a 3M ESPE Elipar ^TM S10 was irradiated with visible light for 20 seconds, and the other side was irradiated by the same method. Shimadzu AGS-X universal testing machine UTM (universal testing machine) was used for the bending strength specimen, and 10 s of Lord Sell and 1 mm / min of crosshead speed were measured. The measurements were carried out in accordance with the International Standardized Test (ISO4049).

According to Fig. 3, the flexural strength of the composition prepared according to Example 2 was the highest, indicating that the flexural strength was excellent. Therefore, it was confirmed that the material prepared according to Example 2 had improved mechanical properties as compared with the materials of Comparative Examples 1 and 2.

Test Example 3: Shrinkage resin compare analysis

Fig. 4 shows the results of analysis of the resin shrinkage ratio of the material produced according to Example 1 and Comparative Examples 1 and 2. Fig.

The method of measuring the shrinkage rate is to measure the shrinkage rate by using a linear variable differential transducer (LVDT) to drop a certain amount of resin into a slide glass, to cover the cover glass, and to move the sample slightly in the direction irradiated with light under the slide glass Respectively.

4, it was confirmed that the compounds prepared according to Example 1 had lower shrinkage than the materials prepared according to Comparative Example 1 and Comparative Example 2. Therefore, it was confirmed that the compound prepared according to Example 1 had relatively superior mechanical properties as compared with the materials prepared according to Comparative Examples 1 and 2.

Test Example 4: Analysis of Water Sorption (Water Sorption)

Fig. 5 shows the results of water absorption analysis of the material produced according to Example 1 and Comparative Examples 1, 2 and 3. Fig.

Measurement specimens for measuring water absorption were prepared by filling a prepared resin mixture with a cylindrical SUS mold (Φ x L = 15 × 1 mm) and using a 3M ESPE Elipar ^™ S10 spot cure apparatus was used to irradiate visible light for 8 seconds around the center and center for 20 seconds, respectively. The water absorption measurement was carried out in accordance with the International Standard Test (ISO4049) as follows. The weight of the prepared specimens was measured, and the specimens were dried until the specimens were uniformly weighed. The weight of M ₀ and was wiped with a specimen of phosphate buffer solution (Phosphate buffer solution, PBS, pH = 7.41) was taken out after 10ml put in a containing vial was allowed to stand for 7 days 37 ℃ oven smooth the sample surface absorptive good paper. Then, it was put in a desiccator for 1 hour, dried and then weighed. At this time, the sample was dried until the weight of the specimen was constant. This weight is called M ₇ . The water absorption was calculated by the following equation.

WS (× x mm ³ ) = M ₇ - M ₀ / V

Where V is the initial volume of the sample.

According to FIG. 5, it was found that the composition prepared according to Example 2 exhibited a lower water absorption than the material of Comparative Example 2. Therefore, it was confirmed that the material prepared according to Example 1 contained in the material of Example 2 had an effect of reducing the water absorption degree.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is possible.

Claims (13)

A compound represented by the following structural formula (1).
[Structural formula 1]

In formula 1,
m And n may be the same or different from each other, and each independently is an integer of 1 to 3,
R ¹ is each independently any one of a hydrogen atom, a methyl group and an ethyl group,
R ² each independently represents a hydrogen atom, a methyl group or an ethyl group The method according to claim 1,
R ¹ each independently represents a hydrogen atom or a methyl group,
And R < ² > are each independently a hydrogen atom or a methyl group. The method according to claim 1,
m And n is 1. The method according to claim 1,
Wherein the compound represented by Formula 1 is a compound represented by Formula 1 below.
[Chemical Formula 1]

Reacting a compound represented by the following structural formula 2 with a compound represented by the following structural formula 3 to prepare a compound represented by the following structural formula 1 (step a); To
≪ / RTI >
[Structural formula 1]

In formula 1,
m And n may be the same or different from each other, and each independently is an integer of 1 to 3,
R ¹ is each independently any one of a hydrogen atom, a methyl group and an ethyl group,
R ² each independently represents a hydrogen atom, a methyl group or an ethyl group.
[Structural formula 2]

In formula 2,
m And n may be the same or different from each other, and each independently is an integer of 1 to 3,
Each R ¹ is independently a hydrogen atom, a methyl group or an ethyl group.
[Structural Formula 3]

In Structure 3,
R ² each independently represents a hydrogen atom, a methyl group or an ethyl group,
X is Cl, Br, I,

And

, ≪ / RTI >
R ³ is any one of a hydrogen atom, a methyl group and an ethyl group,
R < ⁴ > is a C1 to C4 linear or branched alkyl group. 6. The method of claim 5,
Step a,
Preparing the respective compounds represented by the structural formula 2 and the structural formula 3 (step a-1);
A step (a-2) of reacting a compound represented by the structural formula 2 and the structural formula 3 in the step a-1 to prepare a compound represented by the structural formula 1; And
Refining the result of step a-2 (step a-3); To
≪ / RTI > 6. The method of claim 5,
Wherein the reaction is carried out at 20 to < RTI ID = 0.0 > 100 C. < / RTI > 6. The method of claim 5,
Wherein the reaction is carried out for from 12 to 48 hours. The method according to claim 6,
Wherein said purification is carried out by extraction or column chromatography. A material comprising the compound of claim 1. A dental filling material comprising the material of claim 10. 12. The method of claim 11,
Wherein the dental filling material further comprises a compound represented by the following formula (4).
[Chemical Formula 4]

13. The method of claim 12,
Wherein the dental filling material comprises 1 to 30 parts by weight of the compound represented by the structural formula 1 based on 100 parts by weight of the compound represented by the formula (4).

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