A method for preparing a boron-nitrogen compound

Abstract

The application provides a preparation method of a boron-nitrogen compound, and the preparation method comprises the following steps: a coupling reaction of a raw material benzoindole derivative and bromo-chloro-fluorobenzene to obtain an intermediate compound, reaction of the intermediate compound with an aryl boronic acid compound, then a coupling reaction with a carbazole compound, and then a lithiation-boronization-cyclization reaction to obtain a boron-nitrogen compound of formula I. The synthesis method has the advantages of high yield and easy purification of the product.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescence technology and relates to a method for preparing boron nitrogen compounds. Background Technology

[0002] Organic optoelectronic materials are a class of organic materials that possess properties such as the generation, conversion, and transmission of photons and electrons. Currently, the controllable optoelectronic properties of organic optoelectronic materials have been applied to organic light-emitting diodes (OLEDs), organic photovoltaics (OPVs), organic field-effect transistors (OFETs), and even organic lasers. In recent years, OLEDs have become a very popular new type of flat panel display product both domestically and internationally. OLED displays feature self-emissive characteristics, wide viewing angle, short response time, high luminous efficiency, wide color gamut, low operating voltage, thin panels, the ability to manufacture large-size flexible panels, and low cost, earning them the reputation as the star flat panel display product of the 21st century.

[0003] The history of organic electroluminescence can be traced back to the report by Bernanose et al. in 1953 (Holst GA, Kster T, Voges E, et al. FLOX—an oxygen-flux-measuring system using aphase-modulation method to evaluate the oxygen-dependent fluorescence lifetime, ScienceDirect. Sensors and Actuators B: Chemical, 1995, 29, 213.). About 10 years later, in 1963, Pope et al. of New York University observed the fluorescence emission of anthracene by applying a voltage to anthracene crystals (M. Pope, H. Kallmann and P. Magnante, Electroluminescence in Organic Crystals, J. Chem. Phys., 1963, 38, 2042). In 1987, CWTang et al. from Kodak Corporation in the United States used ultrathin film technology, employing aromatic amines with good hole transport performance as the hole transport layer, an aluminum complex of 8-hydroxyquinoline as the light-emitting layer, and indium tin oxide (ITO) thin film and a metal alloy as the anode and cathode, respectively, to fabricate a light-emitting device. This device achieved green light emission with a brightness of up to 1000 cd / m² at a driving voltage of 10V, and its efficiency was 1.5 lm / W (CWTang and S.A. Van Slyke, Organic electroluminescent diodes, Appl. Phys. Lett., 1987, 51, 913). This breakthrough led to the rapid and in-depth development of organic electroluminescence research worldwide. In 1990, Burroughes et al. from Cambridge University proposed the first light-emitting diode based on a polymer (PPV). This indicates that PPV can serve as a highly fluorescent emitting material in monolayer devices, exhibiting high luminescence efficiency (Burroughes JHe et al., Light-emitting diodes based on conjugated polymers, Nature, 1990, 347, 539.).In 1998, Baldo and Forrest et al. from Princeton University reported the first phosphorescent device based on electroluminescence, which in principle could have 100% internal quantum yield (MA Baldo, DFO' Brinetal., Highly efficient phosphorescent emission from organic electroluminescent devices, Nature, 1998, 395, 151). However, on the one hand, phosphorescent materials generally use precious metals such as iridium and platinum, which are expensive. On the other hand, deep blue phosphorescent materials still have chemical instability and large efficiency roll-off problems at high current densities. Therefore, it is extremely important to develop an OLED device that can achieve high-efficiency light emission using inexpensive and stable small organic molecule materials.

[0004] In 2012, the Adachi research group at Kyushu University reported a highly efficient all-fluorescent OLED device based on the thermally activated delayed fluorescence (TADF) mechanism (Uoyama H, Goushi K, Shizu K, et al. Highly efficient organic light-emitting diodes from delayed fluorescence, Nature, 2012, 492(7428):234-238.). When the energy difference between the S1 and T1 levels of a molecule is sufficiently small, the triplet exciton can absorb thermal energy, return to the singlet state through a RISC process, and then emit fluorescence. Theoretically, the internal quantum efficiency (IQE) of this device can reach 100%, and the external quantum efficiency (EQE) can even reach 30%, comparable to the level of phosphorescent devices. As a next-generation light-emitting material, research on TADF materials is booming.

[0005] TADF molecules are mainly used as guest materials to dope in wide-bandgap host materials to achieve high-efficiency thermally activated delayed fluorescence (Q. Zhang, J. Li, K. Shizu, et al. Design of Efficient Thermally Activated Delayed Fluorescence Materials for Pure Blue Organic Light Emitting Diodes, J. Am. Chem. Soc. 2012, 134, 14706; H. Uoyama, K. Goushi, K. Shizu, H. Nomura, C. Adachi, Highly efficient organic light-emitting diodes from delayed fluorescence, Nature, 2012, 492, 234; T. Nishimoto, T. Yasuda, et al. Asix-carbazole-decorated cyclophosphazene as a host with high triplet energy to realize efficient delayed-fluorescence OLEDs, Mater. Horiz. 2014, 1, 264). Unlike traditional fluorescent molecules that emit light from localized (LE) states, TADF emission primarily originates from transitions between ICT states. Therefore, it is easily affected by vibrational and rotational motions between donor and acceptor states, resulting in a broader spectrum. While this broader spectrum is advantageous for lighting applications, it cannot meet the high color purity requirements of the display industry. Since OLEDs are primarily used for displays, a narrow-spectrum design (i.e., a smaller half-width at half-maximum, FWHM) synthesis method for TADF materials is essential. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing boron-nitrogen compounds. The compounds provided by this invention aim to overcome the deficiencies in the synthesis methods of TADF luminescent molecules, offering a method for synthesizing narrow-spectrum luminescent materials. The luminescent compounds involved can be used to prepare the luminescent layer of organic electroluminescent devices, enabling these devices to achieve narrow-spectrum TADF emission.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] On one hand, the present invention provides a method for preparing a boron-nitrogen compound, the method comprising the following steps:

[0009] (1) The coupling reaction between raw material NI and raw material A yields compound BN-I-Br. m The reaction formula is as follows:

[0010]

[0011] Where m = 0, 1, or 2;

[0012] (2) When m=1, compound BN-I-Br1 reacts with raw material BR 3 The coupling reaction (i) yields compound BN-II;

[0013] (i)

[0014] When m = 2, compound BN-I-Br2 reacts with the raw material BR 3 The coupling reaction (ii) yields compound pre-BN-II, which then reacts with the starting material BR. 4 Coupling reaction (iii) occurs to give compound BN-II, as shown in the following reaction formula:

[0015] (ii)

[0016] (iii)

[0017] (3) Compound BN-II undergoes a coupling reaction with starting material C to give compound BN-III, as shown in the following reaction formula:

[0018]

[0019] (4) Compound BN-III undergoes a one-pot lithiation-boration-cyclization reaction with BBr3 to give the boron-nitrogen compound shown in Formula I, as follows:

[0020]

[0021]

[0022] Among them, R 1 and R 2 Independently selected from H, deuterium, fluorine, C1-C20 alkyl, C1-C20 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, and dominated by one or more R a Substituted C6-C18 aryl, 5- to 18-heteroaryl, and substituted with one or more R a Substituted 5- to 18-membered heteroaryl, diphenylamino, or substituted with one or more R a Substituted diphenylamine group; R 1 and R 2They can exist alone or be linked together in a ring via carbon-carbon single bonds;

[0023] R a Each occurrence is independently of deuterium, fluorine, CN, C1-C12 alkyl, C1-C12 alkoxy, C3-C12 cycloalkyl, C6-C14 aryl, and is accompanied by one or more R. b Substituted C6-C14 aryl, 5- to 18-membered heteroaryl, and substituted with one or more R b Substituted 5- to 18-membered heteroaryl, diphenylamino, or substituted with one or more R b Substituted diphenylamine group;

[0024] R b Each occurrence is independently of deuterium, fluorine, CN, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, and is accompanied by one or more R. c Substituted C6-C14 aryl, 5- to 18-membered heteroaryl, and substituted with one or more R c Substituted 5- to 18-membered heteroaryl, diphenylamino, or substituted with one or more R c Substituted diphenylamine group;

[0025] R c Each occurrence is independently of deuterium, fluorine, CN, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, and is accompanied by one or more R. d Substituted C6-C14 aryl, 5- to 18-membered heteroaryl, and substituted with one or more R d Substituted 5- to 18-membered heteroaryl, diphenylamino, or substituted with one or more R d Substituted diphenylamine group;

[0026] R d Each time it appears, it is independently deuterium, fluorine, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, C6-C14 aryl, or is affected by one or more R groups. e Substituted C6-C14 aryl groups;

[0027] R e Each time it appears, it is independently deuterium, fluorine, C1-C12 alkyl, C1-C12 alkoxy, C3-C10 cycloalkyl, or C6-C14 aryl;

[0028] R 3 and R 4 Not simultaneously H or deuterium, and R 3 and R 4Independently selected from H, deuterium, fluorine, C1-C20 alkyl, C1-C20 alkoxy, C3-C12 cycloalkyl, C6-C24 aryl, and dominated by one or more R f Substituted C6-C18 aryl, 5- to 18-heteroaryl, and substituted with one or more R f Substituted 5- to 18-membered heteroaryl, diphenylamino, or substituted with one or more R f Substituted diphenylamine group;

[0029] R f Each time it appears, it is independently deuterium, fluorine, C1-C12 alkyl, C1-C12 alkoxy, C3-C12 cycloalkyl, C6-C14 aryl, 5- to 18-membered heteroaryl or diphenylamino;

[0030] The alkyl, alkoxy, cycloalkyl, aryl, and heteroaryl groups are optionally substituted with one or more substituents selected from the following: halogen, -CN, C1-C12 alkyl, C1-C12 alkoxy, C1-C12 haloalkyl, C2-C6 alkenyl, C3-C10 cycloalkyl, C6-C14 aryl, and 5- to 18-membered heteroaryl.

[0031] Preferably, the R 1 and R 2 Independently, it is H, D (deuterium), fluorine, C1-C12 alkyl, C1-C 12 Alkoxy, C3-C 10 cycloalkyl, phenyl, with at least one C1-C 12 Alkyl-substituted aryl group, with at least one C1-C 12 Alkoxy-substituted aryl, phenyl-C1~C 12 Alkyl, diphenylamino, with at least one C1-C 12 Alkyl-substituted diphenylamino group, carbazole group, or group with at least one C1-C 12 Alkyl-substituted carbazole group.

[0032] Preferably, the R a Each occurrence is independent of deuterium, fluorine, and C1-C2. 12 Alkyl, C1-C 12 Alkoxy, C3-C 10 cycloalkyl, with at least one C1-C 12 Alkyl-substituted phenyl, with at least one C1-C 12 Alkoxy-substituted phenyl, phenyl-C1~C 12 Alkyl, diphenylamino, with at least one C1-C 12 Alkyl-substituted diphenylamino group, carbazole group, or group with at least one C1-C 12 Alkyl-substituted carbazole group.

[0033] Preferably, the R b Each occurrence is independent of deuterium, fluorine, and C1-C2. 12 Alkyl, C1-C 12 Alkoxy, C3-C 10 cycloalkyl, with at least one C1-C 12 Alkyl-substituted phenyl, with at least one C1-C 12 Alkoxy-substituted phenyl, phenyl-C1~C 12 Alkyl, diphenylamino, with at least one C1-C 12 Alkyl-substituted diphenylamino group, carbazole group, or group with at least one C1-C 12 Alkyl-substituted carbazole group.

[0034] Preferably, the R c Each occurrence is independent of deuterium, fluorine, and C1-C2. 12 Alkyl, C1-C 12 Alkoxy, C3-C 10 cycloalkyl, with at least one C1-C 12 Alkyl-substituted phenyl, with at least one C1-C 12 Alkoxy-substituted phenyl, phenyl-C1~C 12 Alkyl, diphenylamino, with at least one C1-C 12 Alkyl-substituted diphenylamino group, carbazole group, or group with at least one C1-C 12 Alkyl-substituted carbazole group.

[0035] Preferably, the R d Each occurrence is independent of deuterium, fluorine, and C1-C2. 12 Alkyl, C1-C 12 Alkoxy, C3-C 10 cycloalkyl, with at least one C1-C 12 Alkyl-substituted phenyl, with at least one C1-C 12 Alkoxy-substituted phenyl, carbazole, or alkyl-substituted phenyl groups with at least one C1-C bond 12 Alkyl-substituted carbazole group.

[0036] Preferably, the R 1 and R 2 Independently, H, deuterium, fluorine, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, hexyl, octyl, decyl, Methoxy, ethoxy, butoxy, hexoxy Cyclohexyl, adamantyl, phenyl, 4-methyl-phenyl, 4-ethyl-phenyl, 4-propyl-phenyl, 4-isopropylphenyl, 4-n-butylphenyl

[0037]

[0038] The wavy lines represent the connection sites of the functional groups.

[0039] Preferably, the R 1 and R 2 Independently H, methyl, Phenyl,

[0040] The wavy lines represent the connection sites of the functional groups.

[0041] Preferably, the R 1 and R 2 Same, selected from H, methyl, Phenyl, any one of them;

[0042] Where R h H, methyl, isopropyl, tert-butyl or

[0043] Preferably, the R 3 and R 4 It is independently selected from H, deuterium, fluorine, C1-C6 alkyl, C3-C12 cycloalkyl, C6-C18 aryl or 5- to 18-heteroaryl.

[0044] Preferably, the reaction in step (1) is carried out in the presence of an alkaline substance;

[0045] Preferably, the alkaline substance in step (1) is cesium carbonate;

[0046] Preferably, the molar ratio of raw material A to raw material NI in step (1) is 1 to 4:1, for example 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1 or 4:1.

[0047] Preferably, the molar ratio of the alkaline substance to the raw material NI in step (1) is 2 to 6:1, for example 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1 or 6:1.

[0048] Preferably, the solvent for the reaction in step (1) is N,N-dimethylformamide.

[0049] Preferably, the reaction temperature in step (1) is 120-160°C (e.g., 120°C, 125°C, 130°C, 140°C, 150°C or 160°C), and the time is 8-24 hours (e.g., 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours or 24 hours).

[0050] Preferably, in step (2) reaction (i), compound BN-I-Br1 reacts with the raw material BR. 3 The molar ratio is 1:1 to 4; for example, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:3.8 or 1:4.

[0051] Preferably, in step (2) reaction (ii), compound BN-I-Br2 reacts with the raw material BR. 3 The molar ratio is 1 to 4:1; for example, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1 or 4:1.

[0052] Preferably, in step (2), reaction (iii) involves compound pre-BN-II reacting with the starting material BR. 4 The molar ratio is 1:1 to 4, for example 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:3.8 or 1:4.

[0053] Preferably, the reactions (i), (ii), and (iii) in step (2) are carried out in the presence of a catalyst.

[0054] Preferably, the catalyst in reactions (i), (ii), and (iii) of step (2) is tetra(triphenylphosphine)palladium.

[0055] Preferably, in step (2), the catalyst in reaction (i) is 0.1% to 10% of the molar amount of compound BN-I-Br1, for example, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0056] Preferably, the catalyst in reaction (ii) of step (2) is the raw material BR. 3 The molar amount is 0.1% to 10%, for example, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0057] Preferably, the catalyst in reaction (iii) of step (2) is the raw material BR. 4The molar amount is 0.1% to 10%, for example, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0058] Preferably, the reactions (i), (ii), and (iii) in step (2) are carried out in the presence of a weakly alkaline substance.

[0059] Preferably, the weakly basic substance in reactions (i), (ii), and (iii) of step (2) is potassium carbonate.

[0060] Preferably, the molar ratio of the weakly basic substance to the compound BN-I-Br1 in the reaction (i) of step (2) is 2 to 8:1, for example 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1 or 8:1.

[0061] Preferably, in step (2) reaction (ii), the weakly alkaline substance reacts with the raw material BR. 3 The molar ratio is 2 to 8:1, for example 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1 or 8:1.

[0062] Preferably, in step (2), the molar ratio of the weakly basic substance to the compound pre-BN-n-II in reaction (iii) is 2 to 8:1, for example, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1 or 8:1.

[0063] Preferably, the solvent for reactions (i), (ii), and (iii) in step (2) is a mixed solution of tetrahydrofuran and water.

[0064] Preferably, the reaction temperature of reactions (i), (ii), and (iii) in step (2) is 60–100°C (e.g., 60°C, 65°C, 70°C, 80°C, 90°C, or 100°C), and the reaction time is independently 6–24 hours (e.g., 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, or 24 hours).

[0065] Preferably, the reaction in step (3) is carried out in the presence of an alkaline substance.

[0066] Preferably, the alkaline substance in step (3) is cesium carbonate.

[0067] Preferably, the molar ratio of compound BN-II to raw material C in step (3) is 1:1 to 4, for example 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:3.8 or 1:4.

[0068] Preferably, the molar ratio of compound BN-II to alkaline substance in step (3) is 1:2 to 6, for example 1:2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5 or 1:6.

[0069] Preferably, the solvent for the reaction in step (3) is N,N-dimethylformamide.

[0070] Preferably, the reaction temperature in step (3) is 120 to 160°C (e.g., 120°C, 125°C, 130°C, 140°C, 150°C or 160°C), and the time is 12 to 24 hours (e.g., 12 hours, 15 hours, 18 hours, 20 hours, 22 hours or 24 hours).

[0071] Preferably, the lithiation stage in the lithiation-boration-cyclization reaction in step (4) is carried out in the presence of an alkyl lithium reagent.

[0072] Preferably, the alkyllithium reagent is tert-butyllithium.

[0073] Preferably, the boration stage in the lithiation-boration-cyclization reaction in step (4) is carried out in the presence of a boron-containing reagent.

[0074] Preferably, the boron-containing reagent in step [1] is boron tribromide.

[0075] Preferably, the cyclization stage in the lithiation-boration-cyclization reaction in step (4) is carried out in the presence of an alkaline substance;

[0076] Preferably, the alkaline substance is N,N-diisopropylethylamine;

[0077] Preferably, the molar ratio of compound BN-III to alkyl lithium reagent in step (4) is 1:2 to 4, for example 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:3.8 or 1:4.

[0078] Preferably, the molar ratio of compound BN-III to boron-containing reagent in step (4) is 1:2 to 6, for example 1:2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5 or 1:6.

[0079] Preferably, the molar ratio of compound BN-III to alkaline substance in step (4) is 1:2 to 8, for example 1:2, 1:2.5, 1:2.8, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:7 or 1:8.

[0080] Preferably, the solvent for the reaction in step (4) is tert-butylbenzene.

[0081] Preferably, in the lithiation-boration-cyclization reaction in step (4), the lithiation stage is carried out at 0 to 60°C (e.g., 0°C, 10°C, 20°C, 30°C, 40°C, 50°C or 60°C), and the reaction time of the lithiation stage is 2 to 6 hours (e.g., 2 hours, 3 hours, 4 hours, 5 hours or 6 hours).

[0082] Preferably, the boronizing stage in the lithiation-boration-cyclization reaction in step (4) is carried out at -40 to 25°C (e.g., -40°C, -30°C, -20°C, -10°C, 0°C, 10°C, 20°C or 25°C), and the reaction time of the boronizing stage is 0.5 to 2 hours (e.g., 0.5 hours, 0.8 hours, 1 hour, 1.5 hours, 1.8 hours or 2 hours).

[0083] Preferably, in step (4), the cyclization stage of the lithiation-boration-cyclization reaction is carried out at 0 to 140°C (e.g., 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 80°C, 100°C, 120°C or 140°C), and the reaction time of the cyclization stage is 6 to 12 hours (e.g., 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours).

[0084] In some embodiments of the present invention, the boron nitrogen compound is any one of the following compounds BN-1 to BN-28:

[0085]

[0086]

[0087] Terminology Explanation

[0088] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0089] As used herein, the terms “containing” or “including (comprise)” can be open-ended, semi-closed, or closed. In other words, the terms also include “consistently made of” or “composed of”.

[0090] Group definition

[0091] In this specification, groups and their substituents may be selected by those skilled in the art to provide stable structural moieties and compounds. When a substituent is described by a conventional chemical formula written from left to right, the substituent also includes chemically equivalent substituents obtained when the structural formula is written from right to left.

[0092] The chapter headings used in this specification are for organizational purposes only and should not be construed as limiting the subject matter. All references or portions thereof cited in this invention, including but not limited to patents, patent applications, articles, books, user manuals, and papers, are incorporated herein by reference in their entirety.

[0093] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter pertains. Where multiple definitions exist for a term, the definition herein shall prevail.

[0094] It should be understood that the singular forms used in this invention, such as "a," include plural references unless otherwise specified. Furthermore, the term "comprising" is an open-ended limitation, not a closed one; that is, it includes the contents specified in this invention but does not exclude other aspects.

[0095] Unless otherwise stated, this invention employs traditional methods of mass spectrometry and elemental analysis, and the steps and conditions can be referred to conventional operating procedures and conditions in the field.

[0096] Unless otherwise specified, this invention employs standard nomenclature and standard laboratory procedures and techniques of analytical chemistry, organic synthetic chemistry, and optics. In some cases, standard techniques are used for chemical synthesis, chemical analysis, and performance testing of light-emitting devices.

[0097] The compounds of the present invention may contain atomic isotopes in non-natural proportions on one or more atoms constituting the compound. For example, the compounds may be labeled with radioactive isotopes, such as deuterium (₂H). All variations in the isotopic composition of the compounds of the present invention, regardless of radioactivity, are included within the scope of the present invention.

[0098] In this invention, unless otherwise specified, the number of "substitutes" can be one or more; when there are multiples, it means two or more, such as two, three, or four. Furthermore, when there are multiple "substitutes," the "substitutes" can be the same or different. In this invention, unless otherwise specified, the position of the "substitute" can be arbitrary.

[0099] In this invention, as a group or part of other groups (e.g., in halogen-substituted alkyl groups), the term "alkyl" means a saturated aliphatic hydrocarbon group comprising branched and straight chains having a specified number of carbon atoms. For example, C1-C1... 20Alkyl groups include straight-chain or branched alkyl groups having 1 to 20 carbon atoms. As defined in "C1-C6 alkyl," it includes groups having 1, 2, 3, 4, 5, or 6 carbon atoms in a straight-chain or branched structure. For example, in this invention, each of the C1-C6 alkyl groups is independently methyl, ethyl, propyl, butyl, pentyl, or hexyl; wherein, propyl is a C3 alkyl group (including isomers, such as n-propyl or isopropyl); butyl is a C4 alkyl group (including isomers, such as n-butyl, sec-butyl, isobutyl, or tert-butyl); pentyl is a C5 alkyl group (including isomers, such as n-pentyl, 1-methyl-butyl, 1-ethyl-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, isopentyl, tert-pentyl, or neopentyl); and hexyl is a C6 alkyl group (including isomers, such as n-hexyl or isohexyl).

[0100] As used herein, the term "alkoxy" refers to an alkyl group as defined above, connected via oxygen bonds (-O-). In this invention, as part of a group or other group, the term "Cn-m aryl" refers to a monocyclic or polycyclic aromatic group (with only carbon atoms as ring atoms) having n to m ring carbon atoms, possessing at least one carbon ring with a conjugated π-electron system. Examples of the aforementioned aryl units include phenyl, naphthyl, indene, azulel, fluorenyl, phenanthryl, or anthraceneyl. In one embodiment, the aryl group is preferably a C6-14 aryl group, such as phenyl and naphthyl, more preferably phenyl.

[0101] In this invention, as a group or part of other groups, the term "nm-aryl" refers to an aromatic group whose ring atoms comprise one or more (e.g., 1, 2, 3, and 4) heteroatoms selected from nitrogen, oxygen, and sulfur, having n to m ring atoms. The heteroaryl group is a monocyclic, bicyclic, tricyclic, or tetracyclic system, wherein at least one ring is an aromatic ring. Heteroaryl groups within this definition include, but are not limited to: acridinel, carbazolyl, cyclophosphinyl, quinoxalinyl, pyrazolyl, indolyl, benzotriazolyl, furanyl, thiophene, benzothiophene, benzofuranyl, quinolinyl, isoquinolinyl, oxazolyl, isoxazolyl, pyrazinyl, pyridinyl, pyrimidinel, pyrroleyl, tetrahydroquinoline, imidazolyl, triazolyl, tetrazolyl, thiazolyl, isothiazolyl, furazolyl, thiadiazolyl, etc. Oxadiazole, pyridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, triazinyl, purine, pteridinyl, naphridinyl, quinazolinyl, phthalazinyl, imidazopyridinyl, imidazothiazolyl, imidazooxazinyl, benzothiazolyl, benzooxazinyl, benzoimidazolyl, isoindolyl, indazole, pyrrolopyridinyl, thienopyridinyl, furanolopyridinyl, benzothiadiazole, benzooxadiazole, pyrrolopyrimidinyl, thienofuranyl. In one embodiment, as preferred examples of "5- to 18-membered heteroaryl groups", furanyl, thienoyl, pyrrololyl, imidazolyl, thiazolyl, pyrazolyl, oxazolyl, isoxazolyl, isothiazolyl, pyridinyl, pyrimidinyl, and carbazoleyl are listed, more preferably carbazoleyl.

[0102] As used herein, the term Cn-Cm cycloalkyl refers to a monocyclic or polycyclic alkyl group having n to m carbon atoms, such as C3-C10 and C3-C6 cycloalkyl groups. Examples include adamantyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and dicycloheptyl. In one embodiment, the C3-C10 cycloalkyl group is preferably adamantyl or cyclohexyl.

[0103] In this invention, the defined carbon number range of a group refers to any integer number of carbon atoms included within the defined range. For example, C1 to C20 means that the number of carbon atoms in the group can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20. C3 to C10 means that the number of carbon atoms in the group can be 3, 4, 5, 6, 7, 8, 9 or 10. The defined carbon number range of other groups is analogous.

[0104] Without violating common sense in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0105] The reagents and raw materials used in this invention are all commercially available.

[0106] Compared with the prior art, the present invention has the following beneficial effects:

[0107] The synthesis method provided by this invention has the advantages of high yield and easy product purification.

[0108] This invention first addresses the selection of raw materials. Specifically, the chlorine atom in the brominated chlorofluorobenzene must be positioned between two fluorine atoms, as the reaction between the benzoindole derivative and this raw material is a nucleophilic substitution reaction. Only by using this type of (F-Cl-F) raw material can this substitution reaction be completed in high yield (above 90%). The main reason is that the electron-withdrawing effect of halogen atoms is ranked as F>Cl>Br. When using F-Br-F type raw materials, the weaker electron-withdrawing effect of Br results in a weaker positive charge on the carbon atom bonded to F, making it impossible to achieve a high-yield nucleophilic substitution reaction with the benzoindole compound.

[0109] On the other hand, regarding the choice of synthetic sequence, this invention selects the halogenated raw material to react with benzoindole first, at which point the carbon atom bonded to F has the strongest positive charge and the highest reactivity. However, if, as in the synthetic sequence of CN114466851A, the raw material is first reacted with phenylboronic acid to generate a biphenyl halide, the newly introduced benzene ring forms a conjugation with the halogenated raw material, reducing the positive charge of the carbon atom bonded to F and decreasing the reactivity, ultimately resulting in a lower yield (approximately 50%) as in CN114466851A. Furthermore, studies have found that when subsequent coupling reactions with the raw material C are performed, the target compound cannot be successfully prepared following the synthetic sequence in CN114466851A.

[0110] It is worth noting that, compared to other aromatic amine compounds (carbazole, modified carbazole, phenothiazine, phenotoxazine, etc.), the target product can be obtained in high yield regardless of whether the route sequence of this invention is followed or the route in CN114466851A. However, the benzoindole aromatic amine of this invention (which is less active than carbazole, etc.) can only be obtained in high yield and easily purified by the synthetic route of this invention. Detailed Implementation

[0111] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0112] In embodiments of the present invention, the raw materials used to synthesize the shown compounds are as follows:

[0113] The specific raw material Am (m=1-2) used includes the following molecules:

[0114]

[0115] The specific raw material Bk (k = 1-6) used includes the following molecules:

[0116]

[0117] The specific raw material Ch (h = 1-4) used includes the following molecules:

[0118]

[0119] Synthesis Examples

[0120] The specific synthetic route involved in this invention is as follows:

[0121] Step 1:

[0122] (1)

[0123] Step Two:

[0124] (2)(i)

[0125] (ii)

[0126] (iii)

[0127] Step 3:

[0128] (3)

[0129] Step Four:

[0130] (4)

[0131] In the first step, starting material Am (m = 1-2) (6 mmol), starting material Ni 1.91 g (6 mmol), and cesium carbonate 3.94 g (12 mmol) were added to 100 mL of N,N-dimethylformamide. The mixture was bubbled with nitrogen for 10 minutes, and the system was heated to 160°C and stirred for 12 hours. After the reaction system cooled to room temperature, the reaction mixture was extracted with dichloromethane and water. The organic phase was dried under vacuum by heating, and then purified by column chromatography to obtain the precursor BN-n-Br. m .

[0132] In the second step, when m=1, the precursor BN-I-Br1 (4 mmol), the starting material Bk (k=1-9) (5 mmol), potassium carbonate 1.10 g (8 mmol), and H2O (12 mL) were added to tetrahydrofuran (80 mL). The mixture was bubbled with nitrogen for 10 minutes, and 116 mg of tetra(triphenylphosphine)palladium (0.10 mmol) was added under high flow nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, the organic phase was dried under vacuum, and then purified by column chromatography to obtain the precursor BN-n-II.

[0133] When m=2, precursor BN-nI (5 mmol), starting material Bk (k=1-9) (5 mmol), potassium carbonate 1.38 g (10 mmol), and H2O (12 mL) were added to tetrahydrofuran (80 mL). The mixture was bubbled with nitrogen for 10 minutes, and 116 mg of tetra(triphenylphosphine)palladium (0.10 mmol) was added under high flow rate nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, the organic phase was dried under vacuum, and then purified by column chromatography to obtain precursor pre-BN-n-II.

[0134] Subsequently, the precursor pre-BN-n-II (4 mmol), starting material Bk (k = 1-9) (5 mmol), potassium carbonate 1.10 g (8 mmol), and H₂O (12 mL) were added to tetrahydrofuran (80 mL). The mixture was bubbled under nitrogen for 10 minutes, and 116 mg of tetra(triphenylphosphine)palladium (0.10 mmol) was added under high flow nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, the organic phase was dried under vacuum, and then purified by column chromatography to obtain the precursor BN-n-II.

[0135] In the third step, precursor BN-n-II (3 mmol), starting material Ch (h = 1-4) (3 mmol), and cesium carbonate 1.97 g (6 mmol) were added to 80 mL of N,N-dimethylformamide. The mixture was bubbled with nitrogen for 10 minutes, and the system was heated to 160°C and stirred for 12 hours. After the reaction system cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, and the organic phase was dried under vacuum by heating. Then, the mixture was purified by column chromatography to obtain precursor BN-n-III.

[0136] In the fourth step, under a nitrogen atmosphere, 3.10 mL of a pentane solution of tert-butyllithium (1.30 M, 4 mmol) was slowly added dropwise to a 60 mL solution of BN-n-III (2 mmol) in tert-butylbenzene at 0 °C. The mixture was then heated to 60 °C and reacted for 2 hours. The temperature was then lowered to -40 °C, and 1.00 g (4 mmol) of boron tribromide (BBr3) was slowly added. The mixture was then heated to room temperature and stirred for 0.5 hours. The temperature was then lowered to 0 °C, and 1.03 g (8 mmol) of N,N-diisopropylethylamine was added. The reaction mixture was then continued at 140 °C for 6 hours before being stopped. After the reaction system cooled to room temperature, the reaction was quenched with 5 mL of methanol and 5 mL of water. The reaction mixture was extracted with dichloromethane and water, and the organic phase was evaporated to dryness under vacuum. The resulting product, BN-n, was then purified by column chromatography. Data on the obtained target compound are shown in Table 1.

[0137] Taking compound BN-1 as an example, the specific experimental details of the synthesis examples are explained below:

[0138] In the first step, 1.36 g of compound A-1 (6 mmol), 1.91 g of starting material Ni (6 mmol), and 3.94 g of cesium carbonate (12 mmol) were added to 100 mL of N,N-dimethylformamide. The mixture was bubbled with nitrogen for 10 minutes, and the system was heated to 160°C and stirred for 12 hours. After the reaction system cooled to room temperature, the reaction mixture was extracted with dichloromethane and water. The organic phase was dried under vacuum by heating, and then purified by column chromatography to obtain 2.95 g of precursor BN-1-Br1 (yield 93%).

[0139] In the second step, 2.11 g of precursor BN-1-Br1 (4 mmol), 0.61 g of compound B-1 (5 mmol), 1.10 g of potassium carbonate (8 mmol), and H2O (12 mL) were added to tetrahydrofuran (80 mL). The mixture was bubbled under nitrogen for 10 minutes, and 116 mg of tetra(triphenylphosphine)palladium (0.10 mmol) was added under high flow rate nitrogen. The mixture was heated to reflux and stirred for 12 hours. After the reaction system cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, the organic phase was dried under vacuum by heating, and then purified by column chromatography to give 1.97 g of precursor BN-1-II (yield 94%).

[0140] In the third step, 1.57 g of precursor BN-1-II (3 mmol), 0.84 g of compound C-1 (3 mmol), and 1.97 g of cesium carbonate (6 mmol) were added to 80 mL of N,N-dimethylformamide. The mixture was bubbled with nitrogen for 10 minutes, and the system was heated to 160°C and stirred for 12 hours. After the reaction system cooled to room temperature, the reaction mixture was extracted with dichloromethane and water, and the organic phase was dried under vacuum by heating. Then, it was purified by column chromatography to obtain 2.18 g of precursor BN-120-III (yield 93%).

[0141] In the fourth step, under a nitrogen atmosphere, 3.10 mL of a pentane solution of tert-butyllithium (1.30 M, 4 mmol) was slowly added dropwise to a 60 mL solution of 1.56 g of BN-1-III (2 mmol) at 0 °C. The mixture was then heated to 60 °C and reacted for 2 hours. The temperature was then lowered to -40 °C, and 1.00 g (4 mmol) of boron tribromide was slowly added. The mixture was then heated to room temperature and stirred for 0.5 hours. The temperature was then lowered to 0 °C, and 1.03 g (8 mmol) of N,N-diisopropylethylamine was added. The reaction mixture was then continued at 140 °C for 6 hours before being stopped. After the reaction system cooled to room temperature, the reaction was quenched with 5 mL of methanol and 5 mL of water. The reaction mixture was extracted with dichloromethane and water, and the organic phase was evaporated to dryness under vacuum. The resulting product was then purified by column chromatography to obtain 0.78 g of the target product, BN-120 (yield 51%).

[0142] Table 1. Summary of product data from the synthesis examples

[0143] compound Raw material 1 Raw material three Raw material four Raw material five molecular weight Elemental analysis (%) (C, H, N) BN-1 A-1 B-1 — C-1 756.11 C, 88.31; H, 5.97; N, 3.73 BN-2 A-1 B-2 — C-1 811.87 C, 88.75; H, 6.56; N, 3.44 BN-3 A-1 B-3 — C-1 868.52 C, 88.03; H, 7.11; N, 3.20 BN-4 A-1 B-4 — C-1 831.77 C, 89.62; H, 5.92; N, 3.37 BN-5 A-1 B-5 — C-1 832.25 C, 89.52; H, 5.90; N, 3.32 BN-6 A-1 B-6 — C-1 908.16 C, 89.73; H, 5.89; N, 3.10 BN-7 A-1 B-1 — C-2 880.78 C, 89.68; H, 5.60; N, 3.15 BN-8 A-1 B-2 — C-2 936.04 C, 89.48; H, 6.15; N, 2.96 BN-9 A-1 B-3 — C-2 992.44 C, 89.25; H, 6.58; N, 2.84 BN-10 A-1 B-4 — C-2 956.83 C, 90.07; H, 5.61; N, 2.95 BN-11 A-1 B-5 — C-2 956.22 C, 90.42; H, 5.55; N, 2.94 BN-12 A-1 B-6 — C-2 1032.57 C, 90.71; H, 5.54; N, 2.70 BN-13 A-1 B-1 — C-3 796.54 C, 90.66; H, 4.67; N, 3.53 BN-14 A-1 B-2 — C-3 852.65 C, 90.02; H, 5.31; N, 3.31 BN-15 A-1 B-3 — C-3 908.48 C, 89.69; H, 5.85; N, 3.09 BN-16 A-1 B-4 — C-3 872.69 C, 90.46; H, 4.74; N, 3.25 BN-17 A-1 B-5 — C-3 872.38 C, 90.88; H, 4.71; N, 3.22 BN-18 A-1 B-6 — C-3 948.15 C, 91.21; H, 4.77; N, 2.96 BN-19 A-1 B-1 — C-4 908.24 C, 89.63; H, 5.87; N, 3.05 BN-20 A-1 B-2 — C-4 964.65 C, 89.52; H, 6.36; N, 2.87 BN-21 A-1 B-3 — C-4 1020.07 C, 89.43; H, 6.79; N, 2.72 BN-22 A-1 B-4 — C-4 984.62 C, 90.02; H, 5.80; N, 2.85 BN-23 A-1 B-5 — C-4 984.74 C, 89.98; H, 5.79; N, 2.86 BN-24 A-1 B-6 — C-4 1060.33 C, 90.29; H, 5.76; N, 2.66 BN-25 A-2 B-1 B-1 C-1 832.17 C, 89.38; H, 5.96; N, 3.33 BN-26 A-2 B-3 B-1 C-1 944.28 C, 88.85%; H, 6.95%; N, 2.94%. BN-27 A-2 B-5 B-1 C-1 908.29 C, 89.74; H, 5.90; N, 3.07 BN-28 A-2 B-6 B-1 C-1 983.84 C, 90.35; H, 5.81; N, 2.82

[0144] Table 2

[0145]

[0146]

[0147] Comparative Synthesis Examples

[0148] Another possible synthetic route for compound BN-1 is as follows:

[0149] (RA-1) (RA-2)

[0150] (RA-3)

[0151] (RA-4)

[0152] The first reaction step RA-1 described above proceeds without issue, yielding the intermediate in high yield. However, a problem arose in the second reaction step, RA-2. When the reaction was carried out according to the reaction conditions given in the published literature (see: CN114466851A) or by trying other possible reaction conditions, the molecular structure of the main product obtained was as follows:

[0153]

[0154] The specific reaction equations and reaction conditions are shown in Table 3.

[0155]

[0156] Table 3

[0157]

[0158] Take 1 mL of the reaction solution, add 2 mL of deionized water and 2 mL of dichloromethane, centrifuge, and take the lower organic phase for HPLC analysis. The specific experimental results are shown in Table 4 below:

[0159] Table 4

[0160] reaction Content of A after the reaction B content after reaction C content after reaction D content after reaction Reaction 1 3.38％ 68.24％ 2.12％ 25.61％ Reaction 2 4.71％ 54.46％ 14.66％ 23.43％ Reaction 3 3.45％ 39.70％ 1.92％ 12.54％

[0161] Although mass spectrometry analysis showed that the reaction mixture contained the following molecules:

[0162]

[0163] However, due to the very low concentration of this molecule in the reaction mixture, it could not be successfully isolated. Therefore, compound BN-1 could not be synthesized using the above reaction route (i.e., via the four-step reactions RA-1, RA-2, RA-3, and RA-4). In contrast to the synthetic raw materials, synthetic method, and route in this invention, the intermediates in the published literature (see: CN114466851A) are... The main reasons for the inability to achieve high yields of the reaction with benzoindole are: 1. The electron-withdrawing ability of the bromine atom is weaker than that of the chlorine atom; 2. Biphenyl first attaches to the benzene ring, and due to the conjugation effect, the charge of the carbon atom attached to F is dispersed. These two factors combined reduce the reactivity of the fluorine atom in the intermediate with benzoindole, thus preventing the high-yield acquisition of the next intermediate.

[0164] Due to the unique reactivity of the benzoindole group, the synthetic method of this invention can significantly improve the reaction yield and facilitate product separation. It is worth noting that those skilled in the art will understand that other aromatic amines (carbazole, carbazone, carbazole derivatives, etc.) can also yield the target product in high yield using either the synthetic route of this invention or the reaction routes described in published literature (see: CN114466851A). It is precisely because of the unique reactivity of the benzoindole group that the synthetic method of this invention can yield the target product in high yield.

[0165] The applicant declares that the preparation method of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for producing a boron-nitrogen compound, characterized by, The preparation method includes the following steps: (1) Coupling reaction of raw material NI and raw material A to obtain compound BN-I-Br m , the reaction formula is as follows: ； Where m = 1 or 2; (2) when m = 1, compound BN-I-Br1 is coupled with starting material B-R 3 to give compound BN-II by coupling reaction (i); ； When m=2, compound BN-I-Br2 reacts with the raw material BR 3 The coupling reaction (ii) yields compound pre-BN-II, which then reacts with the starting material BR. 4 Coupling reaction (iii) occurs to give compound BN-II, as shown in the following reaction formula: ； ； (3) Compound BN-II undergoes a coupling reaction with starting material C to give compound BN-III, as shown in the following reaction formula: ； (4) Compound BN-III undergoes a one-pot lithiation-boration-cyclization reaction with BBr3 to obtain the boron-nitrogen compound shown in Formula I, as follows: ； wherein R 1 and R 2 are independently selected from C1-C20 alkyl, phenyl, R 3 and R 4 Not simultaneously H or deuterium, and R 3 and R 4 Independently selected from H, deuterium, and C6~C24 aryl groups; The alkyl, phenyl, or aryl groups may be optionally substituted with one or more substituents selected from the following: C1-C12 alkyl or C6-C14 aryl.

2. The production method according to claim 1, characterized by, said R 1 and R 2 are independently C1-C12 alkyl or phenyl.

3. The preparation method according to claim 1, characterized in that, The R 1 and R 2 Independently, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, hexyl, phenyl, 4-methyl-phenyl, 4-ethyl-phenyl, 4-propyl-phenyl, 4-isopropylphenyl, 4-n-butylphenyl, or The wavy line represents the connection site of the functional group.

4. The preparation method according to claim 1, characterized in that, The R 1 and R 2 Independently methyl, , phenyl, , or The wavy line represents the connection site of the functional group.

5. The preparation method according to claim 1, characterized in that, said R 3 and R 4 are independently selected from H, deuterium, Ci-C6alkyl, C6-Ci8aryl.

6. The method of claim 1, wherein, The reaction described in step (1) is carried out in the presence of an alkaline substance.

7. The production method according to claim 6, characterized by, The alkaline substance mentioned in step (1) is cesium carbonate.

8. The method of claim 1, wherein, In step (1), the molar ratio of raw material A to raw material Ni is 1~4:

1.

9. The preparation method according to claim 6, characterized in that, The molar ratio of the alkaline substance to the raw material NI in step (1) is 2~6:

1.

10. The method of claim 1, wherein, The solvent for the reaction in step (1) is N,N-dimethylformamide.

11. The method of claim 1, wherein, The reaction in step (1) is carried out at a temperature of 120~160℃ for 8~24 hours.

12. The method of claim 1, wherein, In the reaction (i) of Step (2), the molar ratio of the compound BN-I-Br1 to the starting material B-R 3 is 1:1~4.

13. The method of claim 1, wherein, Step (2) said reaction (ii) in the compound BN-I-Br2and raw material B-R 3 at a molar ratio of 1-4:

1.

14. The method of claim 1, wherein, Step (2) said reaction (iii) in the compound pre-BN-II and raw material B-R 4 at a molar ratio of 1:1~4.

15. The method of claim 1, wherein, The reactions (i), (ii), and (iii) in step (2) proceed in the presence of a catalyst.

16. The method of claim 15, wherein, The catalyst in reactions (i), (ii), and (iii) of step (2) is tetra(triphenylphosphine)palladium.

17. The preparation method according to claim 15, characterized in that, In step (2), the catalyst in reaction (i) is 0.1% to 10% of the molar amount of compound BN-I-Br1.

18. The method of claim 15, wherein, In step (2), the catalyst in reaction (ii) is the raw material BR. 3 0.1% to 10% of the molar amount.

19. The method of claim 15, wherein, The catalyst in the reaction (iii) in step (2) is the raw material B-R 4 0.1%~10% of the molar amount.

20. The preparation method according to claim 11, characterized in that, The reactions (i), (ii), and (iii) in step (2) are carried out in the presence of a weakly basic substance.

21. The method of claim 20, wherein, In step (2), the weakly basic substance in reactions (i), (ii), and (iii) is potassium carbonate.

22. The method of claim 20, wherein, In step (2), the molar ratio of the weakly basic substance to compound BN-I-Br1 in reaction (i) is 2~8:

1.

23. The preparation method according to claim 20, characterized in that, In step (2), the weakly basic substance reacts with the raw material BR in reaction (ii). 3 The molar ratio is 2~8:

1.

24. The method of claim 20, wherein, In step (2), the molar ratio of the weakly basic substance to the compound pre-BN-n-II in reaction (iii) is 2~8:

1.

25. The method of claim 1, wherein, The solvent for reactions (i), (ii), and (iii) in step (2) is a mixed solution of tetrahydrofuran and water.

26. The method of claim 1, wherein, The reaction temperature of reactions (i), (ii), and (iii) in step (2) is 60~100℃, and the reaction time is independently 6~24 hours.

27. The method of claim 1, wherein, The reaction described in step (3) is carried out in the presence of an alkaline substance.

28. The method of claim 27, wherein, The alkaline substance mentioned in step (3) is cesium carbonate.

29. The method of claim 1, wherein, In step (3), the molar ratio of compound BN-II to raw material C is 1:1~4.

30. The method of claim 27, wherein, The molar ratio of compound BN-II to the alkaline substance in step (3) is 1:2~6.

31. The method of claim 1, wherein, The solvent for the reaction in step (3) is N,N-dimethylformamide.

32. The method of claim 1, wherein, The reaction in step (3) is carried out at a temperature of 120~160℃ for 12~24 hours.

33. The method of claim 1, wherein, In step (4), the lithiation stage of the lithiation-boration-cyclization reaction is carried out in the presence of an alkyl lithium reagent.

34. The method of claim 33, wherein, The alkyllithium reagent is tert-butyllithium.

35. The method of claim 1, wherein, In step (4), the borylation stage of the lithiation-boration-cyclization reaction is carried out in the presence of a boron-containing reagent.

36. The method of claim 35, wherein the method is performed in a single step. The boron-containing reagent mentioned in step [1] is boron tribromide.

37. The method of claim 1, wherein, In step (4), the cyclization stage of the lithiation-boration-cyclization reaction is carried out in the presence of an alkaline substance.

38. The method of claim 37, wherein the method is carried out at a temperature of about 20°C to about 30°C. The alkaline substance is N,N-diisopropylethylamine.

39. The preparation method according to claim 33, characterized in that, The molar ratio of compound BN-III to alkyl lithium reagent in step (4) is 1:2~4.

40. The method of claim 35, wherein, In step (4), the molar ratio of compound BN-III to the boron-containing reagent is 1:2~6.

41. The preparation method according to claim 37, characterized in that, The molar ratio of compound BN-III to the alkaline substance in step (4) is 1:2~8.

42. The method of claim 1, wherein, The solvent for the reaction in step (4) is tert-butylbenzene.

43. The method of claim 1, wherein, In step (4), the lithiation stage of the lithiation-boration-cyclization reaction is carried out at 0~60℃, and the reaction time of the lithiation stage is 2~6 hours.

44. The method of claim 1, wherein, In step (4), the boration stage of the lithiation-boration-cyclization reaction is carried out at -40~25℃, and the reaction time of the boration stage is 0.5~2 hours.

45. The preparation method according to claim 1, characterized in that, In step (4), the cyclization stage of the lithiation-boration-cyclization reaction is carried out at 0~140℃, and the reaction time of the cyclization stage is 6~12 hours.

46. The method of making of any one of claims 1-45, wherein, The boron-nitrogen compound is any one of the following compounds BN-1 to BN-28: 。

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