WO2024250588A1 - Method for synthesizing biborate having high-abundance boron isotope - Google Patents

Abstract

The present invention relates to a method for synthesizing biborate having a high-abundance boron isotope. The method comprises the following steps: (1) preparation of (N¹,N²-dimethyl o-phenylenediamine)fluoroborane: N¹,N²-dimethyl o-phenylenediamine, a hydrocarbon solvent A, a high-abundance boron isotope boron trifluoride solution, and a base implement a reaction to obtain the product; (2) preparation of (N¹,N²-dimethyl o-phenylenediamine)chloroborane: (N¹,N²-dimethyl o-phenylenediamine)fluoroborane, a hydrocarbon solvent B, and chlorosilane implement a reaction to obtain the product; (3) coupling: a hydrocarbon solvent C, metal sodium, and a hydrocarbon solution of (N¹,N²-dimethyl o-phenylenediamine)chloroborane implement a reaction, and then washing and drying are carried out to obtain an N¹,N²-dimethyl o-phenylenediamine diboron compound containing a high-abundance boron isotope; and (4) esterification: a hydrocarbon solvent E, the N¹,N²-dimethyl o-phenylenediamine diboron compound, diol, and a hydrocarbon solution of hydrogen chloride implement a reaction, and then washing and drying are carried out to obtain diborate having a high-abundance boron isotope. The present invention has mild reaction conditions and high conversion rate.

Description

A method for synthesizing diborates with high-abundance boron isotopes Technical Field

The invention relates to the field of organic compound synthesis, and in particular to a method for synthesizing diboric acid esters with high-abundance boron isotopes.

Background Art

Due to the widespread use of boron 10 in the nuclear and medical industries, the effective separation of ¹⁰ B, which has a natural abundance of only 19.8%, is one of the most concerned issues for manufacturers and scientists around the world. Among the various ¹⁰ B enrichment methods, chemical exchange distillation is the most studied method and the only practical method to produce a large amount of ¹⁰ B so far. BF ₃ , as a Lewis acid with excellent electron accepting ability, is usually selected as the raw material for separating high-abundance boron 10 isotopes.

BF ₃ is difficult to expand its application range due to its relatively simple modification method. Boron reagents, especially bis(pinacol)boronate (B ₂ pin ₂ ), are tool molecules mainly used for the boronation of halides and the boronation of alkanes, halides and unsaturated substrates. According to statistics, there are about 15,500 chemical reactions involved in B ₂ pin ₂ and about 15,300 organic boron compounds containing Bpin units. There is no doubt that if a method for synthesizing ¹⁰ B ₂ pin ₂ and other commonly used boron 10 boron compounds is developed, it will greatly enrich the application of ¹⁰ B compounds in various fields.

For naturally abundant borate esters, the existing technologies mostly use boron tribromide (BBr ₃ ) or boron trichloride (BCl ₃ ) as raw materials, but due to separation technology reasons, it is impossible to obtain BBr ₃ and BCl ₃ with high abundance of boron 10 isotope. Currently, the source of high abundance boron 10 isotope is mainly boron trifluoride (BF ₃ ) compound, but because BF has a large base bond energy, it is not easy to further convert. At present, there is no report on any method to convert BF ₃ compound into biboric acid ester.

Summary of the invention

The technical problem to be solved by the present invention is to provide a method for synthesizing high-abundance boron isotope biboric acid esters with mild reaction conditions and high conversion rate.

In order to solve the above problems, the method for synthesizing a diboric acid ester with high abundance boron isotope according to the present invention comprises the following steps:

(1) Preparation of (N ¹ ,N ² -dimethyl o-phenylenediamino)fluoroborane:

Add N ¹ , N ² -dimethyl-o-phenylenediamine and hydrocarbon solvent A to reactor A, then add high-abundance boron isotope boron trifluoride solution and base to react, add hydrocarbon solvent A to the system after the reaction is completed, stir, centrifuge, and vacuum dry the filtrate to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)fluoroborane;

The ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the hydrocarbon solvent A is 1 g: 1-15 ml; the molar ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the high-abundance boron isotope boron trifluoride solution is 1.0: 1.0-10.0 equivalents; the molar ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the base is 1.0: 1.0-5.0 equivalents;

(2) Preparation of (N ¹ ,N ² -dimethyl o-phenylenediamino)chloroborane:

Add the (N ¹ , N ² -dimethyl-o-phenylenediamino)fluoroborane and hydrocarbon solvent B into reactor B, then add chlorosilane, react, and after the reaction is completed, vacuum concentrate to obtain (N ¹ , N ² -dimethyl-o-phenylenediamino)chloroborane;

The ratio of the (N ¹ , N ² -dimethyl-o-phenylenediamino)fluoroborane to the hydrocarbon solvent B is 1 g: 1-15 ml; the molar ratio of the (N ¹ , N ² -dimethyl-o-phenylenediamino)fluoroborane to the chlorosilane is 1.0: 0.5-5.0 equivalents;

⑶ Coupling:

Add hydrocarbon solvent C and metallic sodium into reactor C, then add hydrocarbon solution of (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane, react, cool the system after the reaction is completed, filter and dry the filtrate to obtain a solid crude product; wash the solid crude product with n-hexane, filter again and dry to obtain a N ¹ , N ² -dimethyl-o-phenylenediamine boron compound containing high-abundance boron isotopes;

The amount of the hydrocarbon solvent C is 1 to 10 ml per millimole of sodium; the molar ratio of (N ¹ , N ^{2 -dimethyl} -o-phenylenediamino)chloroborane to the metallic sodium in the hydrocarbon solution of (N ¹ , N ² -dimethyl-o-phenylenediamino)chloroborane is 1.0:1.0 to 6.0 equivalents, and the ratio of (N ¹ , N ² -dimethyl-o-phenylenediamino)chloroborane to the hydrocarbon solvent is 1 g:1 to 15 ml;

⑷ Esterification:

Add hydrocarbon solvent E and the N ¹ , N ² -dimethyl o-phenylenediamine boron compound into reactor D, then add diol, and then add hydrogenated hydrocarbon solution, heat up and react, after the reaction is completed, cool the system, filter through diatomaceous earth, and concentrate until there is no fraction to obtain a solid; wash the solid with n-hexane to obtain a boron ester with high abundance of boron isotope;

The ratio of the N ¹ , N ² -dimethyl-o-phenylenediamine boron compound to the hydrocarbon solvent E is 1 g: 1-30 ml; the molar ratio of the N ¹ , N ² -dimethyl-o-phenylenediamine boron compound to the diol is 1.0: 1.0～3.0 equivalents; the molar ratio of the N ¹ , N ² -dimethyl-o-phenylenediamine boron compound to the hydrocarbon solution of hydrogen chloride is 1.0:1.0～15.0 equivalents; the ratio of the N ¹ , N ² -dimethyl-o-phenylenediamine boron compound to the n-hexane is 1g:1～10ml.

In the step (1), the structure of N ¹ , N ² -dimethyl o-phenylenediamine is as shown in formula (I), or it is replaced by N ¹ , N ² -dimethylethylenediamine of formula (II) and N ¹ , N ² -dimethyl-1,8-naphthalenediamine of formula (III), or it is replaced by any one of the structures shown in formula (IV) to formula (VI):

Wherein: R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently selected from an aryl group, an alkyl group having 1 to 12 carbon atoms, an alkenyl group and an alkynyl group, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are different; and n represents a carbon atom number of 1 to 3.

In the step (1), the hydrocarbon solvent A is selected from one of n-heptane, n-hexane or cyclohexane.

In the step (1), the high-abundance boron isotope boron trifluoride solution is selected from one of boron trifluoride ethers, ketones, amines and tetrafluoroborate compounds, or is a boron trifluoride compound of natural abundance.

In step (1), the base is selected from N,N-diisopropylethylamine as shown in formula (VII) or has the structure shown in (VIII); in step (2), the chlorosilane is selected from tetrachlorosilane as shown in formula (IX) or has the structure shown in any one of formulas (X) to (XII):

Wherein: R ⁹ , R ¹⁰ and R ¹¹ are each independently selected from any one of an alkyl group, an aryl group, an alkenyl group and an alkynyl group having 1 to 6 carbon atoms, and R ⁹ , R ¹⁰ and R ¹¹ are different; R ¹² , R ¹³ and R ¹⁴ are each independently selected from a hydrogen atom and any one of an alkyl group, an aryl group, an alkenyl group and an alkynyl group having 1 to 18 carbon atoms, and R ¹² , R ¹³ and R ¹⁴ are different.

The base is selected from any one or a combination of two or more of N,N-diisopropylethylamine, triethylamine, trimethylamine, N-methylmorpholine, 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undec-7-ene and pyridine compounds; the chlorosilane is selected from one of tetrachlorosilane, monomethyltrichlorosilane, dimethyldichlorosilane or trimethylchlorosilane.

The hydrocarbon solvent B in step (2) and the hydrocarbon solvent C in step (3) are each independently selected from one of n-heptane, n-hexane, cyclohexane, toluene or xylene.

The (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane is prepared by a one-pot method:

Add N ¹ , N ² -dimethyl-o-phenylenediamine and n-hexane into reactor E, dropwise add high-abundance boron isotope boron trifluoride solution, alkali and chlorosilane at room temperature, react at 0°C to 120°C until the reaction is completed as detected by NMR; add hydrocarbon solvent into the system, stir, centrifuge, and vacuum dry the filtrate to obtain (N ¹ , N ^{2 -dimethyl} -o-phenylenediamine) chloroborane; the ratio of the N ¹ , N ² -dimethyl-o-phenylenediamine to the n-hexane is 1 g: 1 to 20 ml;

The molar ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the high-abundance boron isotope boron trifluoride solution is 1.0:1.0-10.0 equivalents; the molar ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the chlorosilane is 1.0:0.5-5.0 equivalents; the molar ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the base is 1.0:0.0-5.0 equivalents.

In step (3), the hydrocarbon solution of (N ¹ ,N ^{2 -dimethyl} -o-phenylenediamino)chloroborane is prepared by dissolving 1 g of (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane in 1-15 ml of hydrocarbon solvent D; the hydrocarbon solvent D is selected from toluene or xylene.

In the step (4), the hydrocarbon solvent E is selected from one of n-heptane, toluene or xylene.

The hydrocarbon solution of hydrogen chloride in step (4) is a solution obtained by dissolving hydrogen chloride in ether solution or hydrogen chloride 1,4-dioxane solution.

In the step (4), the diol has a structure as shown in any one of formula (XIII) to formula (XXI):

In the step (1), a high-abundance boron isotope boron trifluoride solution and a base are added at 0°C to 25°C; the reaction temperature is 0°C to 120°C.

The step (2) is performed by adding chlorosilane at 0°C to 50°C; the reaction temperature is 0°C to 120°C.

In the step (3), the hydrocarbon solution of (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane is added at 0°C to 120°C; the reaction temperature is 0°C to 120°C; the system is cooled to 20°C to 50°C; and the washing temperature is 0°C to 50°C.

The addition of diol in step (4) is carried out at 10°C to 30°C; the addition of the hydrocarbon solution of hydrogen chloride is carried out at -78°C to 30°C; the reaction temperature is 25°C to 120°C; the system is cooled to 15 to 25°C; and the washing temperature is 0°C to 50°C.

The steps (1), (2), (3) and (4) are completed by NMR detection.

The biborate is a biborate with high abundance of boron 10 isotope or a biborate with high abundance of boron 11 isotope.

When synthesizing the high-abundance boron-10 isotope biborate, a high-abundance boron-10 isotope boron trifluoride solution is added in step (1).

When synthesizing the high-abundance boron-11 isotope biborate, a high-abundance boron-11 isotope boron trifluoride solution is added in step (1).

The present invention also provides a high-abundance boron isotope biborate obtained by the method.

Compared with the prior art, the present invention has the following advantages:

1. The present invention uses high-abundance boron 10 isotope boron trifluoride or high-abundance boron 11 isotope boron trifluoride, N ¹ ,N ² -dimethyldiamine compounds, chlorosilane, metallic sodium and diol as starting materials, can synthesize chloroborane by a one-step method or a two-step method, and then prepare a variety of boron 10 biborates or boron 11 biborates through coupling and esterification, which lays a foundation for large-scale production.

2. The N ¹ ,N ² -dimethyl-o-phenylenediamine compound used in the present invention can be recovered in equivalent amount after the esterification step, thus saving costs.

3. The products obtained in each step of the present invention are continuously added to the next step in the form of solution, the operation is simple and easy, the reaction yield and product purity of each step are very high, and the total yield can reach 35% to 65%.

4. The reaction conditions of the present invention are mild and the conversion rate is high. The synthesis method can be scaled up to the kilogram level, providing practical synthesis conditions for the large-scale production of high-abundance boron-10 isotope biborates or high-abundance boron-11 isotope biborates.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a comparison of the GC-MS data of B ₂ pin ₂ and ¹⁰ B ₂ pin ₂ .

DETAILED DESCRIPTION

The embodiments of the present invention will be described in detail below in conjunction with examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used can be obtained commercially.

The present invention provides a method for synthesizing a diboric acid ester with high-abundance boron isotope, comprising the following steps:

(1) Preparation of (N ¹ ,N ² -dimethyl o-phenylenediamino)fluoroborane:

N ¹ , N ² -dimethyl-o-phenylenediamine and hydrocarbon solvent A are added to reactor A, and a high-abundance boron isotope boron trifluoride solution and a base are added dropwise at 0°C to 25°C. After the addition is completed, the reaction is carried out at 0°C to 120°C until the reaction is completed as detected by NMR. After the reaction is completed, hydrocarbon solvent A is added to the system, the system is stirred and centrifuged, and the filtrate is vacuum dried to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)fluoroborane.

Wherein: the ratio of N ¹ , N ² -dimethyl-o-phenylenediamine to hydrocarbon solvent A is 1 g: 1-15 ml, preferably 3-15 ml; the molar ratio of N ¹ , N ² -dimethyl-o-phenylenediamine to high-abundance boron isotope boron trifluoride solution is 1.0: 1.0-10.0 equivalents, preferably 1.0: 1.0-5.0 equivalents; the molar ratio of N ¹ , N ² -dimethyl-o-phenylenediamine to base is 1.0: 1.0-5.0 equivalents, preferably 1.0: 2.0-3.0 equivalents.

The structure of N ¹ ,N ² -dimethyl o-phenylenediamine is as shown in formula (I), or it can be replaced by N ¹ ,N ² -dimethylethylenediamine of formula (II) and N ¹ ,N ² -dimethyl-1,8-naphthalenediamine of formula (III), or it can be replaced by any structure shown in formula (IV) to formula (VI):

Wherein: R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ refer to any one of aryl, alkyl having 1 to 12 carbon atoms, alkenyl and alkynyl, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are different; n represents the number of carbon atoms of 1 to 3.

The hydrocarbon solvent A refers to one of n-heptane, n-hexane or cyclohexane, preferably n-hexane.

The high-abundance boron isotope boron trifluoride solution refers to one of boron trifluoride ethers, ketones, amines and tetrafluoroborate compounds, or a boron trifluoride compound of natural abundance.

(2) Preparation of (N ¹ ,N ² -dimethyl o-phenylenediamino)chloroborane:

Add (N ¹ , N ² -dimethyl-o-phenylenediamino)fluoroborane and hydrocarbon solvent B into reactor B, add chlorosilane dropwise at room temperature, react at 0°C to 120°C until the reaction is completed as detected by NMR; after the reaction is completed, concentrate in vacuo to obtain (N ¹ , N ² -dimethyl-o-phenylenediamino)chloroborane.

The ratio of (N ¹ , N 2 ^-dimethyl -o-phenylenediamino)fluoroborane to hydrocarbon solvent B is 1 g: 1-15 ml, preferably 5-15 ml; the molar ratio of (N ¹ , N ² -dimethyl-o-phenylenediamino)fluoroborane to chlorosilane is 1.0: 0.5-5.0 equivalents, preferably 1.0: 1.0-4.0 equivalents.

The hydrocarbon solvent B refers to one of n-heptane, n-hexane, cyclohexane, toluene or xylene, preferably toluene.

⑶ Coupling:

Add hydrocarbon solvent C and metallic sodium into reactor C, stir and reflux until the metallic sodium is completely melted, add dropwise a hydrocarbon solution of (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane at 0°C to 120°C, maintain the temperature unchanged until the reaction is completed as detected by NMR; after the reaction is completed, cool the system to 20°C to 50°C, filter and dry the filtrate to obtain a solid crude product; wash the solid crude product with n-hexane at 0°C to 50°C, filter again and dry to obtain a N ¹ , N ² -dimethyl-o-phenylenediamine boron compound containing high-abundance boron isotopes.

The amount of hydrocarbon solvent C is 1-10 ml per millimole of sodium; the molar ratio of (N ¹ , N ^{2 -dimethyl} -o-phenylenediamino)chloroborane to metallic sodium in the hydrocarbon solution of (N ¹ , N ^{2 -dimethyl} -o-phenylenediamino)chloroborane is 1.0:1.0-6.0 equivalents, preferably 1.0:2.0-3.0 equivalents; and the ratio of (N ¹ , N ² -dimethyl-o-phenylenediamino)chloroborane to hydrocarbon solvent is 1 g:1-15 ml.

The hydrocarbon solvent C refers to one of n-heptane, n-hexane, cyclohexane, toluene or xylene, preferably toluene.

The hydrocarbon solution of (N ¹ ,N ^{2 -dimethyl} -o-phenylenediamino)chloroborane is prepared by dissolving 1 g of (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane in 1-15 ml of a hydrocarbon solvent D; the hydrocarbon solvent D is toluene or xylene.

⑷ Esterification:

Add hydrocarbon solvent E and N ¹ ,N ² -dimethyl-o-phenylenediamine boron compound into reactor D, first add diol at 10°C to 30°C, then add hydrocarbon solution of hydrogen chloride dropwise at -78°C to 30°C, after the dropping is completed, raise the temperature to 25°C to 120°C, and keep the temperature unchanged until the reaction is completed as detected by NMR; after the reaction is completed, cool the system to 15 to 25°C, filter through diatomaceous earth, and concentrate until there is no fraction to obtain a solid; wash the solid with n-hexane at 0°C to 50°C to obtain a boron ester with high abundance of boron isotope.

Wherein: the ratio of N ¹ ,N ² -dimethyl o-phenylenediamine boron compound to hydrocarbon solvent E is 1g:1～ 30ml, preferably 10-30ml; the molar ratio of N ¹ ,N ^{2 -dimethyl} -o-phenylenediamine boron compound to diol is 1.0:1.0-3.0 equivalents, preferably 1.0:2.0-3.0 equivalents; the molar ratio of N ¹ ,N ² -dimethyl-o-phenylenediamine boron compound to hydrocarbon solution of hydrogen chloride is 1.0:1.0-15.0 equivalents; the ratio of N ¹ ,N ² -dimethyl-o-phenylenediamine boron compound to n-hexane is 1g:1-10ml, preferably 1-5ml.

The hydrocarbon solvent E refers to one of n-heptane, toluene or xylene, preferably toluene.

The hydrocarbon solution of hydrogen chloride refers to a solution obtained by dissolving hydrogen chloride in diethyl ether solution or hydrogen chloride 1,4-dioxane solution, preferably diethyl ether.

The diol has a structure as shown in any one of formula (XIII) to formula (XXI):

In the above step (1), the base refers to N,N-diisopropylethylamine as shown in formula (VII) or has the structure shown in (VIII), preferably N,N-diisopropylethylamine, triethylamine, trimethylamine, N-methylmorpholine and any one or a combination of two or more of 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undec-7-ene and pyridine compounds; in step (2), the chlorosilane refers to tetrachlorosilane as shown in formula (IX) or has the structure shown in any one of formulas (X) to (XII), preferably one of tetrachlorosilane, monomethyltrichlorosilane, dimethyldichlorosilane or trimethylchlorosilane.

Wherein: R ⁹ , R ¹⁰ and R ¹¹ are any one of an alkyl group, an aryl group, an alkenyl group and an alkynyl group having 1 to 6 carbon atoms, and R ⁹ , R ¹⁰ and R ¹¹ are different; R ¹² , R ¹³ and R ¹⁴ are a hydrogen atom and any one of an alkyl group, an aryl group, an alkenyl group and an alkynyl group having 1 to 18 carbon atoms, and R ¹² , R ¹³ and R ¹⁴ are different.

In this method, (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane can also be prepared by a one-pot process:

Add N ¹ ,N ² -dimethyl o-phenylenediamine and n-hexane into reactor E, and add high abundance A boron isotope boron trifluoride solution, a base and chlorosilane are reacted at 0°C to 120°C until the reaction is completed as detected by NMR; a hydrocarbon solvent is added to the system, stirred, centrifuged, and the filtrate is vacuum dried to obtain (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane.

Wherein: the ratio of N ¹ , N ² -dimethyl-o-phenylenediamine to n-hexane is 1 g: 1-20 ml, preferably 5-20 ml; the molar ratio of N ¹ , N ² -dimethyl-o-phenylenediamine to high-abundance boron isotope boron trifluoride solution is 1.0: 1.0-10.0 equivalents, preferably 1.0: 1.0-5.0 equivalents; the molar ratio of N ¹ , N ² -dimethyl-o-phenylenediamine to chlorosilane is 1.0: 0.5-5.0 equivalents, preferably 1.0: 1.0-4.0 equivalents; the molar ratio of N ¹ , N ² -dimethyl-o-phenylenediamine to base is 1.0: 0.0-5.0 equivalents, preferably 1.0: 2.0-3.0 equivalents.

Example 1

The synthesis of high-abundance boron 10-pinacol diboron ester ¹⁰ B ₂ pin ₂ includes the following seven methods:

【Method 1】

(1) Preparation of high-abundance boron 10 (N ¹ ,N ² -dimethyl o-phenylenediamino) fluoroborane:

Add n-hexane solvent (20 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (1.36 g, 10 mmol) to reactor A, and add boron trifluoride diethyl ether (4.2 g, 30 mmol) and N,N-diisopropylethylamine (2.59 g, 20 mmol) with high abundance of boron 10 isotope at 0°C-25°C. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. React for 5 h, add n-hexane solvent (5 mL) to the system, filter, and vacuum dry the filtrate to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)fluoroborane with high abundance of boron 10, with a yield of 71%, which is ready for the next step.

(2) Preparation of (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane with high abundance of boron 10:

Toluene (15 mL) and (N ¹ , N ² -dimethyl-o-phenylenediamino)fluoroborane (7.1 mmol) prepared in the above step were added to reactor B, and tetrachlorosilane (24.0 g, 14.2 mmol) was added dropwise at room temperature. After the addition was completed, the mixture was reacted at 90° C. until the reaction was completed as detected by NMR. After the reaction was completed, the system was concentrated in vacuo to obtain (N ¹ , N ² -dimethyl-o-phenylenediamino)chloroborane with high abundance of boron 10, with a yield of 93%, which was then used for the next step.

(3) Preparation of high-abundance boron 10 di(N ¹ ,N ² -dimethyl o-phenylenediamine) diborane:

Toluene (8 mL) and metallic sodium (184 mg, 8 mmol) were added to the reactor C, and the mixture was stirred and refluxed until the metallic sodium was completely melted. The toluene (8 mL) solution of (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane prepared in the above step was added dropwise at 110° C. After the addition was completed, the temperature was raised to 120° C. until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried to obtain a crude product, which was then washed with n-hexane at 0° C., filtered again, and dried. The obtained solid was a di(N ¹ , N ² -dimethyl-o-phenylenediamine)diborane compound with high abundance of boron 10 isotope, with a yield of 72%, to be used in the next step.

(4) Preparation of high-abundance boron 10 pinacol borate ester:

Toluene solvent (7 mL) and di(N ¹ ,N ² -dimethyl-o-phenylenediamine)diborane compound (662 mg, 2.3 mmol) prepared in the above step were added to reactor D, pinacol (542 mg, 4.6 mmol) was added at 25° C., and hydrogen chloride ether solvent (23 mol) was added dropwise at 0° C. After the addition was completed, the temperature was raised to 80° C. and kept unchanged until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C. and filtered through diatomaceous earth. After filtration, the solution was concentrated to no fraction, and the solid was washed with n-hexane (6 mL) at 0° C. to obtain a high-abundance boron 10 isotope diboronate with a yield of 87%.

【Method 2】

(1) Preparation of (N ¹ ,N ² -dimethyl o-phenylenediamino) chloroborane with high abundance of boron 10:

Add n-hexane solvent (300 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (27.2 g, 200 mmol) to reactor E, and add boron trifluoride diethyl ether (28.4 g, 200 mmol) with high abundance boron 10 isotope, N,N-diisopropylethylamine (51.7 g, 400 mmol) and silicon tetrachloride (34.0 g, 200 mmol) dropwise at 0°C-25°C. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. After the reaction is completed, add n-hexane solvent (50 mL) to the system, filter, and vacuum dry the filtrate. The obtained substance is (N ¹ , N ² -dimethyl-o-phenylenediamine) chloroborane with high abundance boron 10, with a yield of 84%, which is ready for the next step.

(2) Preparation of high-abundance boron 10 di(N ¹ ,N ² -dimethyl o-phenylenediamine) diborane:

Toluene (150 mL) and metallic sodium (5.75 g, 250 mmol) were added to the reactor C, and the mixture was stirred and refluxed until the metallic sodium was completely melted. The toluene (150 mL) solution of (N ¹ , N ² -dimethyl-o-phenylenediamino)chloroborane prepared in the above step was added dropwise at 110° C. After the addition was completed, the temperature was raised to 120° C. until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried to obtain a crude product. The crude product was then washed with n-hexane at 0° C., filtered again, and dried. The obtained solid was a high-abundance boron nitrate. 10 isotopic di(N ¹ ,N ² -dimethyl-o-phenylenediamine)diborane compounds were prepared with a yield of 85% and were ready for the next step.

(3) Preparation of high-abundance boron 10 pinacol borate:

Toluene solvent (150 mL) and di(N ¹ ,N ² -dimethyl-o-phenylenediamine)diborane compound (14.4 g, 50 mmol) prepared in the above step were added to reactor D, pinacol (11.8 g, 100 mmol) was added at 25° C., and hydrogen chloride ether solvent (500 mmol) was added dropwise at 0° C. After the addition was completed, the temperature was raised to 80° C. and kept unchanged until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C. and filtered through diatomaceous earth. After filtration, the solution was concentrated to no fraction, and the solid was washed with n-hexane (6 mL) at 0° C. to obtain a high-abundance boron 10 isotope diboronate with a yield of 80%.

【Method 3】

(1) Preparation of (N ¹ ,N ² -dimethylethylenediamino)chloroborane with high abundance of boron 10:

Add n-heptane solvent (300 mL) and N ¹ , N ² -dimethylethylenediamine (17.63 g, 200 mmol) to reactor E, and add boron trifluoride diethyl ether (28.0 g, 200 mmol) with high abundance boron 10 isotope, N,N-diisopropylethylamine (51.7 g, 400 mmol) and silicon tetrachloride (34.0 g, 200 mmol) dropwise at 0°C-25°C. After the addition is complete, react at 90°C until the reaction is completed as detected by NMR. After the reaction is complete, add n-hexane solvent (50 mL) to the system, filter, and the obtained substance is a (N ¹ , N ² -dimethylethylenediamino)chloroborane solution containing high abundance boron 10 with a yield of 88%, which is ready for the next step.

(2) Preparation of high-abundance boron 10 di(N ¹ ,N ² -dimethylethylenediamine)diborane:

Toluene (150 mL), sodium metal (13.8 g, 600 mmol), and the n-heptane solution of (N ¹ , N ² -dimethylethylenediamine)chloroborane prepared in the above step were added to reactor C, and the temperature was raised to 120° C. until the reaction was completed as detected by NMR. After the reaction, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried to obtain a liquid containing a di(N ¹ , N ² -dimethylethylenediamine)diborane compound with high abundance of boron 10 isotope, with a yield of 81%, which was then used for the next step.

(3) Preparation of high-abundance boron 10 pinacol borate:

Toluene solvent (150 mL) and di(N ¹ ,N ² -dimethylethylenediamine)diborane compound (19.2 g, 100 mmol) prepared in the above step were added to the reactor D, and pinacol (47.2 g, 200 mmol) was added at 25°C. The temperature was raised to 80°C and kept constant until the reaction was completed as detected by NMR. After the reaction, the system was cooled to 25°C and filtered through diatomaceous earth. After filtration, the system was concentrated to no fraction and heated to 40°C using n-hexane. The solid was washed with 5% ethanol (6 mL) to obtain a high-abundance boron 10 isotope biboronate with a yield of 85%.

【Method 4】

(1) Preparation of (N ¹ ,N ² -dimethylethylenediamino)chloroborane with high abundance of boron 10:

Add n-heptane solvent (15 mL) and N ¹ , N ² -dimethylethylenediamine (1.86 g, 10 mmol) into reactor E, and add calcium tetrafluoroborate (2.12 g, 10 mmol), N,N-diisopropylethylamine (2.58 g, 20 mmol) and silicon tetrachloride (1.69 g, 10 mmol) with high abundance of boron 10 isotope at 0°C-25°C dropwise. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. After the reaction is completed, add n-hexane solvent (5 mL) into the system, filter, and the obtained substance is a (N ¹ , N ² -dimethylethylenediamino)chloroborane solution containing high abundance of boron 10 with a yield of 78%, which is ready for the next step.

(2) Preparation of high-abundance boron 10 di(N ¹ ,N ² -dimethylethylenediamine)diborane:

Toluene (15 mL), sodium metal (0.69 g, 30 mmol), and the n-heptane solution of (N ¹ , N ² -dimethylethylenediamine)chloroborane prepared in the above step were added to reactor C, and the temperature was raised to 120° C. until the reaction was completed as detected by NMR. After the reaction, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried to obtain a liquid containing a di(N ¹ , N ² -dimethylethylenediamine)diborane compound with high abundance of boron 10 isotope, with a yield of 81%, which was then used for the next step.

(3) Preparation of high-abundance boron 10 pinacol borate:

Toluene solvent (15 mL) and di(N ¹ ,N ² -dimethylethylenediamine)diborane compound (0.78 g, 2 mmol) prepared in the above step were added to reactor D, and pinacol (0.47 g, 4 mmol) was added at 25° C. The temperature was raised to 80° C. and kept constant until the reaction was completed as detected by NMR. After the reaction, the system was cooled to 25° C. and filtered through diatomaceous earth. After filtration, the solution was concentrated to no fraction, and the solid was washed with n-hexane (1 mL) at 0° C. to obtain a high-abundance boron 10 isotope diboronate with a yield of 85%.

【Method 5】

(1) Preparation of (N ¹ ,N ² -dimethyl-1,8-naphthalenediamine)chloroborane with high abundance of boron 10:

n-Heptane solvent (15 mL) and N ¹ ,N ² -dimethyl-1,8-naphthalenediamine (1.86 g, 10 mmol) were added to the reactor E, and high-abundance boron 10 isotope boron trifluoride diethyl ether (1.41 g, 10 mmol), N,N-diisopropylethylamine (2.58 g, 20 mmol) and silicon tetrachloride (1.69 g, 10 mmol) were added dropwise at 0°C-25°C. After the addition, the mixture was reacted at 90°C until the reaction was completed as detected by NMR. After the reaction, n-hexane solvent (5 mL) was added to the system and filtered. The obtained substance was (N ¹ ,N ² -dimethyl-1,8-naphthalenediamine)chloroborane solution containing high-abundance boron 10 with a yield of 76%, which was then used for the next step.

(2) Preparation of high-abundance boron 10 di(N ¹ ,N ² -dimethyl-1,8-naphthalenediamine)diborane:

Toluene (15 mL), sodium metal (0.69 g, 30 mmol), and the n-heptane solution of (N ¹ , N ² -dimethyl-1,8-naphthalenediamine)chloroborane prepared in the above step were added to reactor C, and the temperature was raised to 120° C. until the reaction was completed as detected by NMR. After the reaction, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried, and then the solid was washed with n-hexane at 0° C. and filtered again. The obtained solid contained di(N ¹ , N ² -dimethyl-1,8-naphthalenediamine)diborane compound with high abundance of boron 10 isotope, with a yield of 71%, and was used for the next step.

(3) Preparation of high-abundance boron 10 pinacol borate:

Toluene solvent (15 mL) and di(N ¹ ,N ² -dimethyl-1,8-naphthalenediamine)diborane compound (0.78 g, 2 mmol) prepared in the above step were added to reactor D, and pinacol (0.47 g, 4 mmol) was added at 25° C. The temperature was raised to 80° C. and kept constant until the reaction was completed as detected by NMR. After the reaction, the system was cooled to 25° C. and filtered through diatomaceous earth. After filtration, the solution was concentrated to no fraction, and the solid was washed with n-hexane (1 mL) at 0° C. to obtain a high-abundance boron 10 isotope diboronate with a yield of 85%.

【Method 6】

(1) Preparation of high-abundance boron 10 di(dimethylamino)chloroborane:

Add n-heptane solvent (30 mL) and dimethylamine (0.92 g, 20 mmol) to reactor E, and add boron trifluoride diethyl ether (1.41 g, 10 mmol), N,N-diisopropylethylamine (2.58 g, 20 mmol) and silicon tetrachloride (1.69 g, 10 mmol) with high abundance of boron 10 isotope at 0°C-25°C. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. After the reaction is completed, add n-hexane solvent (5 mL) to the system, filter, and then obtain a di(dimethylamino)chloroborane solution containing high abundance boron 10 by distillation with a yield of 70%, which is ready for the next step.

(2) Preparation of high-abundance boron 10 tetrakis(dimethylamino)diborane:

Toluene (15 mL), sodium metal (0.69 g, 30 mmol), and the n-heptane solution of di(dimethylamino)chloroborane prepared in the above step were added to the reactor C, and the temperature was raised to 120° C. until the reaction was completed by NMR detection. After the reaction, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried to obtain The liquid is a tetrakis(dimethylamino)diborane compound containing high-abundance boron 10 isotope, with a yield of 76%, to be used for the next step.

(3) Preparation of high-abundance boron 10 pinacol borate:

Toluene solvent (15 mL) and tetrakis(dimethylamino)diborane compound (0.78 g, 2 mmol) prepared in the above step were added to reactor D, and pinacol (0.47 g, 4 mmol) was added at 25°C. The temperature was raised to 80°C and kept constant until the reaction was completed as detected by NMR. After the reaction, the system was cooled to 25°C, filtered through diatomaceous earth, and concentrated to no fraction after filtration. The solid was washed with n-hexane (1 mL) at 0°C to obtain a high-abundance boron 10 isotope diboron ester with a yield of 85%.

【Method 7】

(1) Preparation of high-abundance boron 10 di(tetrahydropyrrolyl)chloroborane:

Add n-heptane solvent (30 mL) and tetrahydropyrrole (1.42 g, 20 mmol) to reactor E, and add boron trifluoride diethyl ether (1.41 g, 10 mmol) with high abundance boron 10 isotope, N,N-diisopropylethylamine (2.58 g, 20 mmol) and silicon tetrachloride (1.69 g, 10 mmol) dropwise at 0°C-25°C. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. After the reaction is completed, add n-hexane solvent (5 mL) to the system, filter, and then obtain a di(tetrahydropyrrolyl)chloroborane solution containing high abundance boron 10 by distillation with a yield of 41%, which is ready for the next step.

(2) Preparation of high-abundance boron-10 tetrakis(tetrahydropyrrolyl)diborane:

Toluene (15 mL), sodium metal (0.69 g, 30 mmol), and the n-heptane solution of di(tetrahydropyrrolyl)chloroborane obtained in the above step were added to the reactor C, and the temperature was raised to 120° C. until the reaction was completed by NMR detection. After the reaction, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried to obtain a solid containing tetra(tetrahydropyrrolyl)diborane compound with high abundance of boron 10 isotope, with a yield of 78/%, to be used in the next step.

(3) Preparation of high-abundance boron 10 pinacol borate:

Toluene solvent (15 mL) and tetrakis(tetrahydropyrrolyl)diborane compound (0.60 g, 1 mmol) prepared in the above step were added to reactor D, and pinacol (0.24 g, 2 mmol) was added at 25°C. The temperature was raised to 80°C and kept constant until the reaction was completed by NMR detection. After the reaction, the system was cooled to 25°C and filtered through diatomaceous earth. After filtration, the mixture was concentrated to no fraction and washed with n-hexane (1 mL) at 0°C. The solid was washed to obtain a high-abundance boron 10 isotope biboronate with a yield of 85% ( ¹ H NMR (400 MHz, CDCl ₃ ) δ1.26 (s, 24H) ppm; ¹³ C NMR (101 MHz, CDCl ₃ ) δ83.5, 25.0 ppm).

Example 2

Method for synthesizing high-abundance boron 10 di(3,4-diethylhexane-3,4-diol)diborane B ₂ Epin ₂ :

(1) Preparation of (N ¹ ,N ² -dimethyl o-phenylenediamino) chloroborane with high abundance of boron 10:

Add n-hexane solvent (15 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (1.36 g, 10 mmol) to reactor E, and add boron trifluoride diethyl ether (1.41 g, 10 mmol) with high abundance boron 10 isotope, N,N-diisopropylethylamine (2.58 g, 20 mmol) and silicon tetrachloride (1.69 g, 10 mmol) dropwise at 0°C-25°C. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. After the reaction is completed, add n-hexane solvent (5 mL) to the system, filter, and vacuum dry the filtrate to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine) chloroborane with high abundance boron 10, with a yield of 84%, which is ready for the next step.

(2) Preparation of high-abundance boron 10 di(N ¹ ,N ² -dimethyl o-phenylenediamine) diborane:

Toluene (8 mL) and metallic sodium (575 mg, 25 mmol) were added to the reactor C, and the mixture was stirred and refluxed until the metallic sodium was completely melted. The toluene (8 mL) solution of (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane prepared in the above step was added dropwise at 110° C. After the addition was completed, the temperature was raised to 120° C. until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried to obtain a crude product, which was then washed with n-hexane at 0° C., filtered again, and dried. The obtained solid was a di(N ¹ , N ² -dimethyl-o-phenylenediamine)diborane compound with high abundance of boron 10 isotope, with a yield of 85%, which was to be used in the next step.

(3) Preparation of ¹⁰ B ₂ Epin ₂ :

Toluene solvent (8 mL) and di(N ¹ ,N ² -dimethyl-o-phenylenediamine)diborane compound (720 mg, 2.5 mmol) prepared in the above step were added to reactor D. 3,4-diethylhexane-3,4-diol (1.74 g, 10 mmol) was added at 25° C. Hydrogen chloride ether solvent (15 mol) was added dropwise at 0° C. After the addition was completed, the temperature was raised to 80° C. and maintained constant until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C., filtered through diatomaceous earth, and separated by column chromatography to obtain ¹⁰ B ₂ Epin ₂ with a yield of 76%.

Example 3

Method for synthesizing high-abundance boron-10 di(neopentyl glycol)diborane B ₂ neop ₂ :

(1) Preparation of (N ¹ ,N ² -dimethyl o-phenylenediamino) chloroborane with high abundance of boron 10:

Add n-hexane solvent (15 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (1.36 g, 10 mmol) to reactor E, and add boron trifluoride diethyl ether (1.41 g, 10 mmol) with high abundance boron 10 isotope, N,N-diisopropylethylamine (2.58 g, 20 mmol) and silicon tetrachloride (1.69 g, 10 mmol) dropwise at 0°C-25°C. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. After the reaction is completed, add n-hexane solvent (5 mL) to the system, filter, and vacuum dry the filtrate to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine) chloroborane with high abundance boron 10, with a yield of 84%, which is ready for the next step.

(2) Preparation of high-abundance boron 10 di(N ¹ ,N ² -dimethyl o-phenylenediamine) diborane:

Toluene (8 mL) and metallic sodium (575 mg, 25 mmol) were added to the reactor C, and the mixture was stirred and refluxed until the metallic sodium was completely melted. The toluene (8 mL) solution of (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane prepared in the above step was added dropwise at 110° C. After the addition was completed, the temperature was raised to 120° C. until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried to obtain a crude product, which was then washed with n-hexane at 0° C., filtered again, and dried. The obtained solid was a di(N ¹ , N ² -dimethyl-o-phenylenediamine)diborane compound with high abundance of boron 10 isotope, with a yield of 85%, which was to be used in the next step.

(3) Preparation of ¹⁰ B ₂ neop ₂ :

Toluene solvent (8 mL) and di(N ¹ ,N ² -dimethyl-o-phenylenediamine)diborane compound (720 mg, 2.5 mmol) prepared in the above step were added to reactor D. Neopentyl glycol (520 mg, 5 mmol) was added at 25° C. Hydrogen chloride ether solvent (25 mol) was added dropwise at 0° C. After the addition was completed, the temperature was raised to 80° C. and kept constant until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C. and filtered through diatomaceous earth. After filtration, the solution was concentrated to no fraction. The solid was washed with n-hexane (0.5 mL) at 0° C. to obtain ¹⁰ B ₂ neop ₂ with a yield of 81%.

Example 4

Method for synthesizing high-abundance boron 10 catechol diboron ester B ₂ cat ₂ :

(1) Preparation of (N ¹ ,N ² -dimethyl o-phenylenediamino) chloroborane with high abundance of boron 10:

n-Hexane solvent (15 mL) and N ¹ ,N ² -dimethyl-o-phenylenediamine (1.36 g, 10 mmol) were added to the reactor E, and high-abundance boron 10 isotope boron trifluoride diethyl ether (1.41 g, 10 mmol), N,N-diisopropylethylamine (2.58 g, 20 mmol) and silicon tetrachloride (1.69 g, 10 mmol) were added dropwise, and the reaction was continued at 90°C until the reaction was completed as detected by NMR. After the reaction, n-hexane solvent (5 mL) was added to the system, and the system was filtered and the filtrate was dried under vacuum to obtain (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane with high abundance of boron 10. The yield was 84%, and the product was used for the next step.

(2) Preparation of high-abundance boron 10 di(N ¹ ,N ² -dimethyl o-phenylenediamine) diborane:

Toluene (8 mL) and metallic sodium (575 mg, 25 mmol) were added to the reactor C, and the mixture was stirred and refluxed until the metallic sodium was completely melted. The toluene (8 mL) solution of (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane prepared in the above step was added dropwise at 110° C. After the addition was completed, the temperature was raised to 120° C. until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried to obtain a crude product, which was then washed with n-hexane at 0° C., filtered again, and dried. The obtained solid was a di(N ¹ , N ² -dimethyl-o-phenylenediamine)diborane compound with high abundance of boron 10 isotope, with a yield of 85%, which was to be used in the next step.

(3) Preparation of ¹⁰ B ₂ cat ₂ :

Toluene solvent (8 mL) and di(N ¹ ,N ² -dimethyl-o-phenylenediamine)diborane compound (720 mg, 2.5 mmol) prepared in the above step were added to reactor D. Catechol (550 mg, 5 mmol) was added at 25° C. Hydrogen chloride ether solvent (37.5 mol) was added dropwise at 0° C. After the addition was completed, the temperature was raised to 80° C. and kept constant until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C. and filtered through diatomaceous earth. After filtration, the mixture was concentrated to no fraction. The solid was washed with acetonitrile and n-hexane at 0° C. to obtain ¹⁰ B ₂ cat ₂ with a yield of 71%.

Example 5

Method for synthesizing high-abundance boron 10-pinacol diboron ester ¹⁰ B ₂ pin ₂ :

n-heptane solvent (7 mL), N ₁ ,N ₂ -dimethyl-o-phenylenediamine boron compound (662 mg, 2.3 mmol) were added to reactor D, pinacol was added at 25° C., hydrogen chloride ether solvent (23 mol) was added dropwise at 0° C., after the addition was completed, the temperature was raised to 80° C. and kept constant until the reaction was completed as detected by NMR; after the reaction was completed, the system was cooled to 25° C., filtered through diatomaceous earth, concentrated to no fraction after filtration, and the solid was washed with n-hexane (6 mL) at 0° C. to obtain a high-abundance boron 10 isotope borate ester with a yield of 87%.

Example 6

Method for synthesizing high-abundance boron 10-pinacol diboron ester ¹⁰ B ₂ pin ₂ :

Toluene solvent (7 mL), N ₁ , N ₂ -dimethyl-o-phenylenediamine boron compound (662 mg, 2.3 mmol) were added to reactor D, pinacol (4.6 mmol) was added at 25° C., and hydrogen chloride 1,4-dioxane solvent (23 mol) was added dropwise at 0° C. After the addition was completed, the temperature was raised to 80° C. and kept constant until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C. and filtered through diatomaceous earth. After filtration, the solution was concentrated to no fraction, and the solid was washed with n-hexane (6 mL) at 0° C. to obtain a high-abundance boron 10 isotope boron ester with a yield of 84%.

Example 7

Synthesis of chiral bis-pinanediol diboronate with high abundance of boron ^{10 10} B ₂ pai ₂ method:

Toluene solvent (7 mL), N ₁ , N ₂ -dimethyl-o-phenylenediamine boron compound (662 mg, 2.3 mmol) were added to reactor D, bis-pinene glycol (4.6 mmol) was added at 25° C., hydrogen chloride ether solvent (23 mol) was added dropwise at 0° C., after the addition was completed, the temperature was raised to 80° C. and kept constant until the reaction was completed as detected by NMR; after the reaction was completed, the system was cooled to 25° C., filtered through diatomaceous earth, concentrated to no fraction after filtration, and the solid was washed with n-hexane (6 mL) at 0° C. to obtain a high-abundance boron 10 isotope boron ester with a yield of 31%.

Example 8

Preparation of high-abundance boron-10 di(2,4-dimethyl-2,4-diol)diborane:

Toluene solvent (2 mL), N ₁ , N ₂ -dimethyl-o-phenylenediamine boron compound (87 mg, 0.3 mmol) were added to reactor D, 2,4-dimethyl-2,4-diol was added at 25° C., hydrogen chloride ether solvent (3 mol) was added dropwise at 0° C. After the addition was completed, the temperature was raised to 80° C. and the temperature was maintained unchanged until the reaction was completed as detected by GC-MS. After the reaction was completed, the system was cooled to 25° C. and filtered. After filtration, the system was concentrated to no fraction, and the solid was washed with n-hexane (2 mL) at 0° C. to obtain di(2,4-dimethyl-2,4-diol)diborane with high abundance of boron 10 isotope, with a yield of 42%.

Example 9

Preparation of (N ¹ ,N ² -dimethyl-o-phenylenediamino)fluoroborane with high abundance of boron 10:

Add n-heptane solvent (20 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (1.36 g, 10 mmol) to reactor A, and add boron trifluoride diethyl ether (4.2 g, 30 mmol) and N,N-diisopropylethylamine (2.59 g, 20 mmol) with high abundance of boron 10 isotope at 0°C-25°C. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. React for 5 h, add n-hexane solvent (5 mL) to the system, filter, and vacuum dry the filtrate to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)fluoroborane with high abundance of boron 10, with a yield of 70%.

Example 10

Preparation of (N ¹ ,N ² -dimethyl-o-phenylenediamino)fluoroborane with high abundance of boron 10:

Cyclohexane solvent (20 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (1.36 g, 10 mmol) were added to reactor A, and boron trifluoride diethyl ether (4.2 g, 30 mmol) and N,N-diisopropylethylamine (2.59 g, 20 mmol) with high abundance of boron 10 isotope were added dropwise at 0°C-25°C. After the addition was completed, the mixture was reacted at 90°C until the reaction was completed as detected by NMR. The reaction was continued for 5 h, and n-hexane solvent (5 mL) was added to the system. The mixture was filtered, and the filtrate was dried under vacuum to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)fluoroborane with high abundance of boron 10, with a yield of 64%.

Embodiment 11

Preparation of (N ¹ ,N ² -dimethyl-o-phenylenediamino)fluoroborane with high abundance of boron 10:

Cyclohexane solvent (20 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (1.36 g, 10 mmol) were added to reactor A, and boron trifluoride diethyl ether (4.2 g, 30 mmol) and triethylamine (2.03 g, 20 mmol) with high abundance of boron 10 isotope were added dropwise at 0°C-25°C. After the addition was completed, the mixture was reacted at 90°C until the reaction was completed as detected by NMR. The reaction was continued for 5 h, and n-hexane solvent (5 mL) was added to the system. The mixture was filtered, and the filtrate was dried under vacuum to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)fluoroborane with high abundance of boron 10, with a yield of 68%.

Example 12

Preparation of (N ¹ ,N ² -dimethyl-o-phenylenediamino)fluoroborane with high abundance of boron 10:

Cyclohexane solvent (20 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (1.36 g, 10 mmol) were added to reactor A, and boron trifluoride diethyl ether (4.2 g, 30 mmol) and pyridine (1.59 g, 20 mmol) with high abundance of boron 10 isotope were added dropwise at 0°C-25°C. After the addition was completed, the mixture was reacted at 90°C until the reaction was completed as detected by NMR. The reaction was continued for 5 h, and n-hexane solvent (5 mL) was added to the system. The mixture was filtered, and the filtrate was dried under vacuum to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)fluoroborane with high abundance of boron 10, with a yield of 41%.

Example 13

Preparation of (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane with high abundance of boron 10:

n-Hexane solvent (2 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (136 mg, 1 mmol) were added to reactor E, and boron trifluoride diethyl ether (140 mg, 1 mmol) with high abundance boron 10 isotope, N,N-diisopropylethylamine (259 mg, 2 mmol) and monomethyltrichlorosilane (449 mg, 3 mmol) were added dropwise at 0°C-25°C. After the addition was completed, the mixture was reacted at 90°C until the reaction was completed as detected by NMR. After the reaction was completed, the mixture was filtered and the filtrate was dried in vacuo to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane with high abundance boron 10, with a yield of 70%.

Embodiment 14

Preparation of (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane with high abundance of boron 10:

Add n-hexane solvent (2 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (136 mg, 1 mmol) to reactor E, and add boron trifluoride diethyl ether (140 mg, 1 mmol) with high abundance boron 10 isotope, N,N-diisopropylethylamine (259 mg, 2 mmol) and dimethyldichlorosilane (388 mg, 3 mmol) dropwise at 0°C-25°C. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. After the reaction is completed, filter and dry the filtrate in vacuo to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine) chloroborane with high abundance boron 10, with a yield of 55%.

Embodiment 15

Preparation of (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane with high abundance of boron 10:

n-Hexane solvent (2 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (136 mg, 1 mmol) were added to reactor E, and boron trifluoride diethyl ether (140 mg, 1 mmol), N,N-diisopropylethylamine (259 mg, 2 mmol) and trimethylsilyl chloride (326 mg, 3 mmol) with high abundance of boron 10 isotope were added dropwise at 0°C-25°C. After the addition was completed, the mixture was reacted at 90°C until the reaction was completed as detected by NMR. After the reaction was completed, the mixture was filtered and the filtrate was dried under vacuum to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine) chloroborane with high abundance of boron 10, with a yield of 37%.

Example 16

Preparation of (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane with high abundance of boron 10:

n-Hexane solvent (2 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (136 mg, 1 mmol) were added to reactor E, and boron trifluoride dimethyl ether (113 mg, 1 mmol) with high abundance boron 10 isotope, N,N-diisopropylethylamine (259 mg, 2 mmol) and tetrachlorosilane (169 mg, 1 mmol) were added dropwise at 0°C-25°C. After the addition was completed, the mixture was reacted at 90°C until the reaction was completed as detected by NMR. After the reaction was completed, the mixture was filtered and the filtrate was dried in vacuo to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane with high abundance boron 10, with a yield of 86%.

Embodiment 17

Preparation of (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane with high abundance of boron 10:

Add n-hexane solvent (2 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (136 mg, 1 mmol) into reactor E, and add boron trifluoride acetone complex (1 mmol) with high abundance boron 10 isotope, N,N-diisopropylethylamine (259 mg, 2 mmol) and tetrachlorosilane (169 mg, 1 mmol) dropwise at 0°C-25°C. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. After the reaction is completed, filter and dry the filtrate in vacuo to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane with high abundance boron 10, with a yield of 80%.

Embodiment 18

Method for synthesizing naturally abundant bis(pinacol)boronic acid ester B ₂ pin ₂ :

(1) Preparation of natural abundance (N ¹ ,N ² -dimethyl o-phenylenediamino) chloroborane:

Add n-hexane solvent (30 mL) and N ¹ , N ² -dimethyl-o-phenylenediamine (2.72 g, 20 mmol) into reactor E, and add naturally abundant boron trifluoride diethyl ether (2.82 g, 20 mmol), N,N-diisopropylethylamine (5.17 g, 40 mmol) and tetrachlorosilane (3.58 g, 20 mmol) dropwise at 0°C-25°C. After the addition is completed, react at 90°C until the reaction is completed as detected by NMR. After the reaction is completed, filter and vacuum dry the filtrate to obtain naturally abundant (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane with a yield of 84%, which is ready for the next step.

⑵ Preparation of natural abundance N ¹ ,N ² -dimethyl o-phenylenediamine boron compound:

Toluene (15 mL) and metallic sodium (1.15 g, 50 mmol) were added to the reactor C, and the mixture was stirred and refluxed until the metallic sodium was completely melted. The toluene (15 mL) solution of (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane prepared in the above step was added dropwise at 110° C. After the addition was completed, the temperature was raised to 120° C. until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried. The solid was then washed with n-hexane at 0° C., filtered again, and dried. The obtained solid was a naturally abundant N ¹ , N ² -dimethyl-o-phenylenediamine boron compound with a yield of 74%, which was then used for the next step.

⑶ Preparation of natural abundance pinacol borate:

Add xylene solvent (15 mL) and the N ¹ , N ² -dimethyl o-phenylenediamine boron compound (1.45 g, 5 mmol) prepared in the above step to the reactor D, add pinacol (1.18 g, 10 mmol) at 25° C., add hydrogen chloride ether solvent (50 mol) dropwise at 0° C., after the addition is completed, the temperature is raised to 80° C. and maintained constant until the reaction is completed as detected by NMR; after the reaction is completed, the system is cooled to 25° C. and filtered through diatomaceous earth. After filtration, the solution is concentrated to no fraction, and solid B is washed with n-hexane (1 mL) at 0° C. to obtain naturally abundant borate ester with a yield of 87%.

Embodiment 19

Method for synthesizing naturally abundant bis(pinacol)boronic acid ester ¹¹ B ₂ pin ₂ :

(1) Preparation of high-abundance boron-11 (N ¹ ,N ² -dimethyl-o-phenylenediamino) chloroborane:

n-Hexane solvent (30 mL) and N ¹ ,N ² -dimethyl-o-phenylenediamine (2.72 g, 20 mmol) were added to the reactor E, and high-abundance boron 11 isotope boron trifluoride diethyl ether (2.82 g, 20 mmol), N,N-diisopropylethylamine (5.17 g, 40 mmol) and tetrachlorosilane (3.58 g, 20 mmol) were added dropwise at 0°C-25°C. After the addition was completed, the mixture was reacted at 90°C until the reaction was completed as detected by NMR. After the reaction was completed, the mixture was filtered and the filtrate was dried under vacuum. The obtained substance is naturally abundant (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane with a yield of 85%, which is ready for the next step.

(2) Preparation of high-abundance boron 11 N ¹ ,N ² -dimethyl o-phenylenediamine boron compound:

Toluene (15 mL) and metallic sodium (1.15 g, 50 mmol) were added to the reactor C, and the mixture was stirred and refluxed until the metallic sodium was completely melted. The toluene (15 mL) solution of (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane prepared in the above step was added dropwise at 110° C. After the addition was completed, the temperature was raised to 120° C. until the reaction was completed as detected by NMR. After the reaction was completed, the system was cooled to 25° C., filtered, and the filtrate was vacuum dried. The solid was then washed with n-hexane at 0° C., filtered again, and dried. The obtained solid was a N ¹ , N ² -dimethyl-o-phenylenediamine boron compound with high abundance of boron 11, with a yield of 72%, which was to be used in the next step.

(3) Preparation of high-abundance boron 11-pinacol boric acid ester:

Add xylene solvent (15 mL) and the N ¹ , N ² -dimethyl o-phenylenediamine boron compound (1.45 g, 5 mmol) prepared in the above step to the reactor D, add pinacol (1.18 g, 10 mmol) at 25° C., add hydrogen chloride ether solvent (50 mol) dropwise at 0° C., after the addition is completed, the temperature is raised to 80° C. and maintained constant until the reaction is completed as detected by NMR; after the reaction is completed, the system is cooled to 25° C. and filtered through diatomaceous earth. After filtration, the solution is concentrated to no fraction, and solid B is washed with n-hexane (1 mL) at 0° C. to obtain high-abundance boron 11 borate ester with a yield of 85%.

It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical deformation made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the protection scope of the present invention.

Claims (21)

A method for synthesizing a diboric acid ester with high abundance of boron isotopes comprises the following steps: (1) Preparation of (N ¹ ,N ² -dimethyl o-phenylenediamino)fluoroborane: Add N ¹ , N ² -dimethyl-o-phenylenediamine and hydrocarbon solvent A to reactor A, then add high-abundance boron isotope boron trifluoride solution and base to react, add hydrocarbon solvent A to the system after the reaction is completed, stir, centrifuge, and vacuum dry the filtrate to obtain (N ¹ , N ² -dimethyl-o-phenylenediamine)fluoroborane; The ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the hydrocarbon solvent A is 1 g: 1-15 ml; the molar ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the high-abundance boron isotope boron trifluoride solution is 1.0: 1.0-10.0 equivalents; the molar ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the base is 1.0: 1.0-5.0 equivalents; (2) Preparation of (N ¹ ,N ² -dimethyl o-phenylenediamino)chloroborane: Add the (N ¹ , N ² -dimethyl-o-phenylenediamino)fluoroborane and hydrocarbon solvent B into reactor B, then add chlorosilane, react, and after the reaction is completed, vacuum concentrate to obtain (N ¹ , N ² -dimethyl-o-phenylenediamino)chloroborane; The ratio of the (N ¹ , N ² -dimethyl-o-phenylenediamino)fluoroborane to the hydrocarbon solvent B is 1 g: 1-15 ml; the molar ratio of the (N ¹ , N ² -dimethyl-o-phenylenediamino)fluoroborane to the chlorosilane is 1.0: 0.5-5.0 equivalents; ⑶ Coupling: Add hydrocarbon solvent C and metallic sodium into reactor C, then add hydrocarbon solution of (N ¹ , N ² -dimethyl-o-phenylenediamine)chloroborane, react, cool the system after the reaction is completed, filter and dry the filtrate to obtain a solid crude product; wash the solid crude product with n-hexane, filter again and dry to obtain a N ¹ , N ² -dimethyl-o-phenylenediamine boron compound containing high-abundance boron isotopes; The amount of the hydrocarbon solvent C is 1 to 10 ml per millimole of sodium; the molar ratio of (N ¹ , N ^{2 -dimethyl} -o-phenylenediamino)chloroborane to the metallic sodium in the hydrocarbon solution of (N ¹ , N ² -dimethyl-o-phenylenediamino)chloroborane is 1.0:1.0 to 6.0 equivalents, and the ratio of (N ¹ , N ² -dimethyl-o-phenylenediamino)chloroborane to the hydrocarbon solvent is 1 g:1 to 15 ml; ⑷ Esterification: Add hydrocarbon solvent E and the N ¹ , N ² -dimethyl o-phenylenediamine boron compound into reactor D, then add diol, and then add hydrocarbon solution of hydrogen chloride, heat up and react, after the reaction is completed, cool the system, filter through diatomaceous earth, and concentrate until there is no fraction to obtain a solid; wash the solid with n-hexane, that is, Obtaining diborates with high abundance of boron isotopes; The ratio of the N ¹ , N ² -dimethyl-o-phenylenediamine boron compound to the hydrocarbon solvent E is 1 g: 1-30 ml; the molar ratio of the N ¹ , N ² -dimethyl-o-phenylenediamine boron compound to the diol is 1.0: 1.0-3.0 equivalents; the molar ratio of the N ¹ , N ^{2 -dimethyl} -o-phenylenediamine boron compound to the hydrocarbon solution of hydrogen chloride is 1.0: 1.0-15.0 equivalents; the ratio of the N ¹ , N ² -dimethyl-o-phenylenediamine boron compound to the n-hexane is 1 g: 1-10 ml. The method for synthesizing a high-abundance boron isotope biboric acid ester according to claim 1, characterized in that: the structure of N ¹ , N ² -dimethyl o-phenylenediamine in step (1) is as shown in formula (I), or is replaced by N ¹ , N ² -dimethylethylenediamine of formula (II) and N ¹ , N ² -dimethyl-1,8-naphthalenediamine of formula (III), or is replaced by a structure as shown in any one of formulas (IV) to (VI):
Wherein: R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently selected from an aryl group, an alkyl group having 1 to 12 carbon atoms, an alkenyl group and an alkynyl group, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are different; and n represents a carbon atom number of 1 to 3. The method for synthesizing a high-abundance boron isotope biboric ester according to claim 1, characterized in that: in the step (1), the hydrocarbon solvent A is selected from one of n-heptane, n-hexane or cyclohexane. The method for synthesizing a high-abundance boron isotope biborate according to claim 1, characterized in that: the high-abundance boron isotope boron trifluoride solution in step (1) is selected from one of boron trifluoride ethers, ketones, amines and tetrafluoroborate compounds, or is a naturally abundant boron trifluoride compound. The method for synthesizing a high-abundance boron isotope biboric acid ester according to claim 1, characterized in that: in the step (1), the base is selected from N,N-diisopropylethylamine shown in formula (VII) or has the structure shown in (VIII); in the step (2), the chlorosilane is selected from tetrachlorosilane shown in formula (IX) or has a structure as shown in any one of formulas (X) to (XII):
Wherein: R ⁹ , R ¹⁰ and R ¹¹ are each independently selected from an alkyl group, an aryl group, an alkene group, R ⁹ , R ¹⁰ and R ¹¹ are different; R ¹² , R ¹³ and R ¹⁴ are each independently selected from a hydrogen atom and an alkyl group having 1 to 18 carbon atoms, an aryl group, an alkenyl group and an alkynyl group, and R ¹² , R ¹³ and R ¹⁴ are different. The method for synthesizing a high-abundance boron isotope biboric acid ester according to claim 5, characterized in that: the base is selected from any one or a combination of two or more of N,N-diisopropylethylamine, triethylamine, trimethylamine, N-methylmorpholine and 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undec-7-ene and pyridine compounds; the chlorosilane is selected from one of tetrachlorosilane, monomethyltrichlorosilane, dimethyldichlorosilane or trimethylchlorosilane. The method for synthesizing a high-abundance boron isotope biboric ester according to claim 1, characterized in that the hydrocarbon solvent B in step (2) and the hydrocarbon solvent C in step (3) are each independently selected from one of n-heptane, n-hexane, cyclohexane, toluene or xylene. The method for synthesizing a high-abundance boron isotope biboric acid ester according to claim 1, characterized in that: the (N ¹ ,N ² -dimethyl-o-phenylenediamino)chloroborane is prepared by a one-pot process: Add N ¹ , N ² -dimethyl-o-phenylenediamine and n-hexane into reactor E, dropwise add high-abundance boron isotope boron trifluoride solution, alkali and chlorosilane at room temperature, react at 0°C to 120°C until the reaction is completed as detected by NMR; add hydrocarbon solvent into the system, stir, centrifuge, and vacuum dry the filtrate to obtain (N ¹ , N ^{2 -dimethyl} -o-phenylenediamine) chloroborane; the ratio of the N ¹ , N ² -dimethyl-o-phenylenediamine to the n-hexane is 1 g: 1 to 20 ml; The molar ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the high-abundance boron isotope boron trifluoride solution is 1.0:1.0-10.0 equivalents; the molar ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the chlorosilane is 1.0:0.5-5.0 equivalents; the molar ratio of the N ¹ , N ² -dimethyl o-phenylenediamine to the base is 1.0:0.0-5.0 equivalents. The method for synthesizing a high-abundance boron isotope biboric acid ester according to claim 1, characterized in that: the hydrocarbon solution of ( ^N1 , ^N2 -dimethyl-o-phenylenediamino)chloroborane in step (3) is prepared by dissolving 1g of ( ^N1 , ^N2 -dimethyl-o-phenylenediamino)chloroborane in 1-15ml of hydrocarbon solvent D; the hydrocarbon solvent D is selected from toluene or xylene. The method for synthesizing a high-abundance boron isotope biboric ester according to claim 1, characterized in that: in the step (4), the hydrocarbon solvent E is selected from one of n-heptane, toluene or xylene. The method for synthesizing a high-abundance boron isotope biboric acid ester according to claim 1, characterized in that: the hydrocarbon solution of hydrogen chloride in step (4) is hydrogen chloride using ether solution or hydrogen chloride 1,4- The resulting solution was dissolved in dioxane solution. The method for synthesizing a high-abundance boron isotope biboric acid ester according to claim 1, characterized in that: the diol in step (4) has a structure as shown in any one of formula (XIII) to formula (XXI):
The method for synthesizing a high-abundance boron isotope biborate according to claim 1, characterized in that: the addition of a high-abundance boron isotope boron trifluoride solution and a base in step (1) is carried out at 0°C to 25°C; the reaction temperature is 0°C to 120°C. The method for synthesizing a high-abundance boron isotope biboric ester according to claim 1, characterized in that: the addition of chlorosilane in step (2) is carried out at 0°C to 50°C; the reaction temperature is 0°C to 120°C. The method for synthesizing a high-abundance boron isotope biboric acid ester according to claim 1, characterized in that: the hydrocarbon solution of ( ^N1 , ^N2 -dimethyl-o-phenylenediamino)chloroborane is added in step (3) at 0°C to 120°C; the reaction temperature is 0°C to 120°C; the system is cooled to 20°C to 50°C; and the washing temperature is 0°C to 50°C. The method for synthesizing a high-abundance boron isotope diborate according to claim 1, characterized in that: the addition of diol in step (4) is carried out at 10°C to 30°C; the addition of hydrogen chloride to the hydrocarbon solution is carried out at -78°C to 30°C; the reaction temperature is 25°C to 120°C; the system is cooled to 15 to 25°C; and the washing temperature is 0°C to 50°C. The method for synthesizing a high-abundance boron isotope biboric acid ester according to claim 1, characterized in that: the steps (1), (2), (3), and (4) are completed by NMR detection of the reaction. The method for synthesizing a high-abundance boron isotope biboric acid ester according to claim 1, characterized in that the biboric acid ester is a high-abundance boron 10 isotope biboric acid ester or a high-abundance boron 11 isotope biboric acid ester. The method for synthesizing a high-abundance boron isotope biborate according to claim 18, characterized in that when synthesizing the high-abundance boron 10 isotope biborate, a high-abundance boron 10 isotope boron trifluoride solution is added in step (1). The method for synthesizing a high-abundance boron isotope biborate according to claim 18, characterized in that when synthesizing the high-abundance boron-11 isotope biborate, a high-abundance boron-11 isotope boron trifluoride solution is added in step (1). A diborate with high abundance of boron isotope obtained by the method according to any one of claims 1 to 20.