KR102651502B1 - Organoboron Compounds and Method for Manufacturing the same - Google Patents

Abstract

The present invention relates to organoboron compounds and methods for their preparation. More specifically, it relates to an organoboron compound with a naphthalene skeleton, which is used as a reactive agent or starting material in organic synthesis.
A novel organic boron compound represented by the following general formula G is provided.
<General formula G>

In the general formula G, R1 to R6 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 16 carbon atoms. R7 and R8 each independently represent hydrogen or an alkyl group having 1 to 6 carbon atoms, and R7 and R8 may be bonded to each other to form a ring. R9 represents any one of an alkyl group having 1 to 6 carbon atoms.

Description

Organoboron Compounds and Method for Manufacturing the Same}

The present invention relates to organoboron compounds and methods for their production. More specifically, it relates to an organoboron compound with a naphthalene skeleton, which is used as a reactive agent or starting material in organic synthesis.

Organic compounds can have a variety of structures compared to inorganic compounds, and with appropriate molecular design, materials with various functions can be supplied. Because of these advantages, the development of materials for organic boron compounds that can be used as synthetic intermediates or starting materials for various organic compounds is continuously being developed.

In general, research on boronic acid did not make much progress until the 1970s, but progressed rapidly after Japanese researchers Suzuki and Miyaura published the cross-coupling reaction between boronic acid derivatives and organic halogen compounds in 1979.

Recently, organic boron compounds have been considered very important as light-emitting materials used in OLED displays, and their application fields are expanding to other fields such as pesticides and bioactive substances.

Boron atoms are metals that have many advantages compared to other heavy metal atoms such as iron, ruthenium, iridium or platinum, as they are non-toxic, relatively easy to use, and can be used biologically. These boron-containing compounds are materials that exhibit unique optical properties and can efficiently emit light through strong quantum absorption at low temperatures, so they are also being researched and developed as lasers, molecular probes, and light-emitting materials.

A variety of boron compounds are being studied, but the types need to be diversified to create excellent materials for light-emitting devices. In addition, in the method of synthesizing boron compounds, obtaining the target product simply and with higher purity is being studied as important, and a reaction that is safer and easier to purify is required.

Patent Document 1 discloses a new organic boron compound that can be used in the production of organic light-emitting diodes, and Patent Documents 2 and 3 provide new organic boron compounds and also disclose organic light-emitting devices using the same.

Patent Document 4 relates to the synthesis of aryl or alkane borates, and dioxaborolein compounds with various substituents are disclosed. Among these, boron compounds with a naphthalene skeleton linked to methoxy as a substituent (see Examples 49, 61, and 65 of the specification) are disclosed, but boron compounds with a methylthio group linked to them are not known.

Domestic registered patent No. 10-1511020 (registration date 2015.04.06.) Domestic Published Patent No. 10-2014-004138 (Published on January 10, 2014) Domestic registered patent No. 10-0492243 (registration date 2005.05.20.) US registered patent US 7,122,694 B2 (registration date 2006.10.17.)

Gwanyong Lee, “Recent advances in the synthesis of organic boronic acids and their derivatives,” KISTI Advanced Technology Information Analysis Report, 2006.09.14.

The object of the present invention is to provide novel organoboron compounds useful as reactive agents in organic synthesis. It has better luminous efficiency and device lifespan than existing materials, and can contribute to synthesizing organic light-emitting materials with excellent skeletons with appropriate color coordinates.

Another object of the present invention is to provide a method for producing the organic boron compound described above.

In one aspect, the present invention provides an organic boron compound represented by the general formula G below.

<General formula G>

(However, in the general formula G, R1 to R6 each independently represent hydrogen, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 16 carbon atoms. R7 and R8 each independently represent hydrogen and 1 carbon atom. Represents any one of an alkyl group with 1 to 6 carbon atoms. R9 represents any one of an alkyl group with 1 to 6 carbon atoms.)

R7 and R8 are characterized in that they combine with each other to form a ring.

In another aspect, the present invention is a method for producing an organic boron compound, which involves producing an organic boron compound represented by the following general formula G by condensing a naphthalene derivative having an alkylthio group and an alkenyl boron ester in the presence of a palladium catalyst and a base. Provides a method.

<General formula G>

In the method for producing the organic boron compound, the base used is potassium acetate, the palladium catalyst is PdCl2(dppf), and the reaction solvent is THF.

In order to promote the reaction and increase the yield, phosphine compounds of PPh3, P-(o-tolyl)3, and PBu3 are used as adducts, or salts of lithium chloride, lithium bromide, and lithium iodide are used as adducts. Do it as

The alkenyl boron ester is a dioxaborolane compound with a 5-membered ring structure and includes Bis(pinacolato)diboron, 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, and 2- It is characterized by being selected from methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane.

The organic boron compounds are useful as light-emitting materials for organic light-emitting devices.

According to one embodiment of the present invention, a new organic boron compound and a method for producing the same can be provided. This organic boron compound can be used not only as a reactive agent in organic synthesis but also as a synthetic intermediate to synthesize various organic compounds.

In addition, according to the production method of the present invention, when synthesizing a specific organic boron compound, it can be obtained or purified with higher purity, and the reaction time is shortened, so it can be produced more inexpensively and simply.

Figure 1 is a reaction flow chart dividing the manufacturing process of the present invention into stages.
Figure 2 shows the HPLC results of an organic boron compound prepared when using a PdCl2(dppf) palladium catalyst and a THF solvent.

Below, preferred embodiments of the present invention and the physical properties of each component are described in detail, but the purpose is to provide a detailed description so that a person skilled in the art can easily practice the invention. This does not mean that the technical idea and scope of the present invention are limited.

The organic boron compound according to an embodiment of the present invention is represented by the general formula G below.

<General formula G>

In the general formula G, R1 to R6 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 16 carbon atoms. R7 and R8 each independently represent hydrogen or an alkyl group having 1 to 6 carbon atoms, and R7 and R8 may be bonded to each other to form a ring. R9 represents any one of an alkyl group having 1 to 6 carbon atoms.

In addition, in this specification, the organic boron compound represented by general formula G also includes boronic acid. For boronic acids, R7 and R8 in general formula G represent hydrogen. Additionally, in the case of boronic acid ester, R7 and R8 in general formula G are alkyl groups having 1 to 6 carbon atoms.

Specific examples of substituents R1 to R6 include hydrogen, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, phenyl group, 1-naphthyl group, and 2-naph group. Til group, 2-anthryl group, 9-anthryl group, pyrene-1-yl group, pyrene-4-yl group, fluoren-2-yl group, etc. are mentioned. Additionally, the aryl group may be selected from phenyl group, 1-naphthyl group, 2-naphthyl group, 2-anthryl group, 9-anthryl group, pyrene-1-yl group, pyrene-4-yl group, fluoren-2-yl group, etc.

In addition, specific examples of the R7 and R8 substituents include hydrogen, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, and cyclopentyl group, respectively. , cyclohexyl group, etc. Additionally, R7 and R8 may be bonded to each other to form a ring, for example, as shown in the following general formulas G1 to G3. Specific examples of the R9 substituent include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, cyclopentyl group, cyclohexyl group, etc. methyl group is most preferred.

<General formula G1>

<General formula G2>

<General formula G3>

Specific examples of the organic boron compound represented by general formula G include organic boron compounds represented by chemical structural formulas 1 to 9. However, the present invention is not limited to these.

<Chemical formula 1>

<Chemical formula 2>

<Chemical formula 3>

<Chemical formula 4>

<Chemical formula 5>

<Chemical formula 6>

<Chemical formula 7>

<Chemical formula 8>

<Chemical formula 9>

As a method for synthesizing the organic boron compound represented by general formula G, various reactions can be applied. For example, an organic boron compound represented by general formula G can be synthesized by performing the synthesis reaction shown below. Additionally, the method for synthesizing the organic boron compound represented by general formula G, which is one embodiment of the present invention, is not limited to the following synthesis method.

In the present invention, various organic boron compounds were prepared by condensing a naphthalene derivative having an alkylthio group and an alkenyl boron ester in the presence of a palladium catalyst and a base. For detailed synthesis methods, refer to the examples below, and Figure 1 shows a reaction flow chart dividing the manufacturing process of the present invention into stages.

The naphthalene derivative having the alkylthio group may further have various substituents, of which a halogen group is preferable.

The palladium catalysts include Pd2(dba)3, Pd(PPh3)4, Pd(OAc)2, Pd[P(t-Bu)3]2, PdCl2(PPh3)2, PdCl2((P(o-tolyl) 3)2, PdCl2(dppf), PdCl2(dppe), PdCl2(dppp), etc. Among these, PdCl2(dppf) is the most preferable.

In addition, to promote the reaction and increase the yield, phosphine compounds such as PPh3, P-(o-tolyl)3, and PBu3 can be used as adducts, or salts such as lithium chloride, lithium bromide, and lithium iodide can be used as adducts. You can.

Because the bond between carbon and boron is quite strong, the metal exchange reaction does not proceed unless a base is present. Therefore, it is necessary to activate the boron compound so that the metal exchange reaction can proceed by adding an equivalent amount or more of base to the reaction system.

Hydroxides of alkali metals or alkaline earth metals may be used as the base, and sodium methoxide, cesium acetate, potassium acetate, etc. are preferred.

In the present invention, various alkenyl boron esters can be used in the condensation reaction, and among them, dioxaborolane with a five-membered ring structure is preferable, and a specific example is Bis(pinacolato)diboron ( ), 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane ( ), 2-Methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane ( ), etc. can be used.

Through the above reaction, an organic boron compound represented by the general formula G is produced.

<General formula G>

The description of the substituents of R1 to R8 is the same as previously mentioned. That is, in the general formula G, R1 to R6 each independently represent hydrogen, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 16 carbon atoms. R7 and R8 each independently represent hydrogen or an alkyl group having 1 to 6 carbon atoms, and R7 and R8 may be bonded to each other to form a ring. R9 represents any one of an alkyl group having 1 to 6 carbon atoms.

In particular, when dioxaborolane with a 5-membered ring structure is used, an organic boron compound represented by the general formula G1 is produced.

<General formula G1>

The organic boron compound of the present invention exhibits strong light-emitting properties and can be usefully used in the production of organic light-emitting devices (OLEDs).

The process for preparing the compound of the present invention will be looked at with a focus on examples as follows. In particular, the present invention was differentiated by using specific catalysts and solvents for shortened reaction time, high yield, and high purity.

Preparation Example 1. Preparation of Methyl(naphthalen-1-yl)sulfane

Dissolve 11.289 g (0.0704 mol) of naphthalene-1-thiol in 140 g of acetone in a round flask, add 3.382 g (0.083 mol) of sodium hydroxide at room temperature, and stir to completely dissolve. When sodium hydroxide is completely dissolved, add 10 g (0.0704 mol) iodomethane at room temperature and reflux for 5 hours.

After 5 hours, the reaction solution was distilled under reduced pressure to remove acetone, 150 ml dichloromethane and 150 ml water were added, stirred for 30 minutes, and the layers were separated. The separated organic layer is treated with magnesium sulfate, dried, filtered, and the filtrate is concentrated to remove the solvent. 11.90 g (0.0682 mol) of light ivory-colored powder is obtained as Methyl(naphthalen-1-yl)sulfane. -1-yl)sulfane) was obtained. At this time, the yield was 97.0% and the purity was 96.71%.

Meanwhile, when the solvent was changed from acetone to ethanol under the same reaction conditions, the yield was relatively low at 93.2%, but the purity was higher at 99.1%.

Preparation Example 2. Preparation of (2-bromonaphthalen-1-yl)(methyl)sulfane

Add 11.9 g (0.0682 mol) of the compound (Methyl(naphthalen-1-yl)sulfane, hereinafter referred to as ‘A’) prepared in Preparation Example 1 to a round flask and dissolve it in 114 g of DMF. Add 12.56 g (0.071 mol) N-bromosuccinimide (NBS) at room temperature and stir for 30 minutes. Pour the reaction solution into ice water, add 300ml ethyl acetate, stir for 30 minutes, and separate the layers. At this time, the temperature of the reaction solution must be controlled so that it does not rise more than 5 degrees. By drying and filtering the separated organic layer and concentrating the filtrate, a crude liquid product with a purity of 98.2% can be obtained, which can be purified by short column chromatography (flow solvent: heptane) to obtain 15.4 g (0.0608 mol) of yellow oily (2-bromonaphthalen-1-yl)methylsulfane (hereinafter referred to as 'B') was obtained in 88.2% yield (Scheme 1 below) reference).

[Scheme 1]

Example. Synthesis of 4,4,5,5-tetramethyl-2-(1-(methylthio)naphthalen-2-yl)-1,3,2-dioxaborolane

15 g (0.059 mol) of (2-bromonaphthalene-1-yl)(methyl)sulfane prepared in Preparation Example 2 was dissolved in 150 ml THF solvent while injecting nitrogen into a round flask, and then the reaction solution was cooled to -78°C. After cooling, the palladium catalyst, base, and solvent required for the cross-linking reaction were added to this reaction solution as shown in Table 1 below, and slowly added dropwise in an amount 1.3 times the equivalent of compound B in Preparation Example 2.

After everything was injected, the reaction solution was raised to -30°C and maintained for 3 hours, and then the reaction solution was cooled to -78°C again and after 1 hour, 2-isopropoxy-4,4,5,5- was added as an introducer. Tetramethyl-1,3,2-dioxaborolane (2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, hereinafter referred to as 'PT diborone') was added to the reactant 1.4 times more frequently. Add an equivalent amount and react for 3 hours, then raise the temperature to room temperature over 1 hour.

Afterwards, the reaction was further performed at room temperature for 1 hour, then refluxed for 1 hour, and then cooled to room temperature. Add 200 ml of ethyl acetate and 300 ml of distilled water and separate the layers. The organic layer is dried, filtered, and concentrated under reduced pressure.

When concentrated and recrystallized with n-heptane, 4,4,5,5-tetramethyl-2-(1-methylthionaphthalen-2-yl)-1,3,2-dioxaborolein (4) is obtained as a white solid. , 4,5,5-tetramethyl-2-(1-(methylthio)naphthalen-2-yl)-1,3,2-dioxaborolane, hereinafter referred to as 'C') product can be obtained (see Scheme 2 below) .

[Scheme 2]

This C compound is an organic boron compound represented by the chemical structural formula 1 of the present invention.

<Chemical formula 1>

To prepare the product, various catalysts and solvents were selected, and the results of HPLC analysis are summarized in Table 1 and Figure 2.

The solvent includes ether-based solvents such as tetrahydrofuran (THF), dioxane, dichloromethane, and 1,2-dimethoxyethane, aromatic hydrocarbon solvents such as benzene, toluene, and xylene, dimethylformamide, and dimethyl sulfoxide ( DMSO), acetonitrile, etc. can be used alone or in combination.

Experiment example Introduced product (boron ester) base catalyst reaction solvent HPLC (%) reaction time introduction impurity 1 impurity 2 product
(water) One P.T.
diborone Potassium Acetate PdCl2(dppf) toluene 15.88 0.89 3.32 80.81 3 hours 2 PdCl2(dppf) DMSO 23.91 2.21 7.66 67.55 7 hours 3 PdCl2(dppf) dioxane 27.32 1.21 10.68 60.12 12 hours 4 PdCl2(dppf) dioxane 1.81 1.00 0.69 94.88 19 hours 5 PdCl2(dppf) THF 1.61 1.00 0.90 97.16 6 hours 6 Pd2(dba)3 dioxane 49.33 0.26 0.96 49.44 12 hours 7 Pd(OAc)2/
P(t-bu)3 dioxane 51.73 - 46.46 1.81 14 hours * PdCl2(dppf): 1,1'-Bis(di-tert-butylphosphino)-ferrocene]palladium(II) Dichloride
* Pd2(dba)3: Tris(dibenzylideneacetone)-dipalladium(0)
* Pd(OAc)2/P(t-bu)3: Palladium(II) Acetate/tris(tert-butyl)phosphine

The above Experimental Examples 1 to 7 show the results of preparations using the same introducer (PT diboron) and the same base under different catalysts and reaction solvents. PdCl2 (dppf) was selected as the palladium catalyst and THF as the solvent. In the case of Experimental Example 5, a product with a synthetic purity of 97.16% was obtained, and when this was recrystallized with n-heptane, the yield was 80% and the purity could be increased to 99.5%. This case had the highest purity compared to other experimental examples, and it was the most economical synthesis reaction as it could be produced quickly with a reaction time of 6 hours.

Figure 2 is a picture of the HPLC results of the product prepared in Experimental Example 5. The amount of unreacted introduced matter was the lowest at 1.61% (peak #7, Area%), and the purity of the product was analyzed to be 97.16% (peak #9, Area%).

Although the same palladium catalyst PdCl2(dppf) was used, when dioxane was used as a solvent (Experimental Examples 3 and 4), there were relatively more unreacted substances, and the reaction time was 2 to 3 times longer than that of Experimental Example 5. Even if the purity was increased by more than twofold, the purity of the products was only 60.12% and 94.88%, respectively.

In other words, using THF as a solvent had the advantage of being able to produce the product more quickly and with high purity. This is very important as it can reduce costs in the production process.

In the above, the present invention has been described in detail focusing on embodiments, but it is obvious to those skilled in the art that various variations and modifications are possible within the technical scope of the present invention, and it is natural that such variations and modifications fall within the scope of the appended patent claims. will be.

Claims (10)

delete delete delete delete As a method for producing an organic boron compound,
In the presence of a PdCl2 (dppf) palladium catalyst and a potassium acetate base, tetrahydrofuran (THF) was selected as the reaction solvent, and naphthalene with a methylthio group and 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2- Method for producing a 97.16% high purity organic boron compound represented by the following chemical formula 1 by condensing dioxaborolane
<Chemical structural formula 1>
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