Key bromine-containing intermediate for synthesizing TADF molecule and synthesis method of key bromine-containing intermediate

Abstract

The invention discloses three key bromine-containing intermediates for synthesizing TADF molecules and a synthesis method of the key bromine-containing intermediates. The method comprises the following steps: constructing an intermediate through a palladium-catalyzed carbon-nitrogen coupling reaction and a palladium-catalyzed carbon-sulfur coupling reaction, and finally constructing a final product through the palladium-catalyzed carbon-nitrogen coupling reaction. According to the method, 4-tert-butyl aniline, 4-tert-butyl aniline, 3, 6-di-tert-butyl carbazole and di (4-tert-butyl phenyl) amine are adopted as raw materials, commercially available palladium acetate and phosphine ligands are used as a catalytic system for reaction to effectively synthesize three key bromine-containing intermediates for synthesizing TADF molecules, the method is mild in reaction condition, the yield is excellent, and the method is suitable for industrial production. The method is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis and relates to a key bromine-containing intermediate for synthesizing TADF molecules and a synthesis method thereof. Background Art

[0002] Carbon-nitrogen coupling and carbon-sulfur coupling reactions are important reactions in organic synthesis and are widely used in fields such as materials science. Through these reactions, scientists can efficiently construct complex organic molecules containing sulfur and nitrogen, which has greatly promoted the development of modern organic chemistry and materials chemistry. Transition metal catalysts and their ligands play a vital role in the successful implementation of these two types of coupling reactions. The catalytic system composed of palladium catalysts and phosphine ligands is one of the most commonly used catalytic systems in these coupling reactions and is widely used due to its superiority in improving reaction selectivity and substrate adaptability.

[0003] The research on organic light-emitting materials initially relied mainly on the luminescence mechanism of singlet excitons. However, in traditional organic optoelectronic materials, triplet excitons usually lose energy through non-radiative transitions, resulting in low luminescence efficiency. To break through this bottleneck, thermally excited delayed fluorescence (TADF) materials came into being. The core advantage of TADF materials lies in their smaller energy gap (ΔE) between triplet and singlet excitons. ST ), which is usually less than 0.3 eV, which enables triplet excitons to be converted into singlet excitons through a thermal excitation process, thereby effectively participating in radiative transitions and releasing photons, significantly improving the luminescence efficiency.

[0004] In 2016, Hatakeyama et al. developed boron-nitrogen co-doped polycyclic aromatic hydrocarbons (DABNA) and proposed the concept of the "multiple resonance" (MR) effect for the first time (Hatakeyama T, Shiren K, Nakajima K, et al. Ultrapure Blue Thermally Activated Delayed Fluorescence Molecules: Efficient HOMO-LUMOS separation by the Multiple Resonance Effect [J]. Advanced. Mater. 2016, 28 (14): 2777-2781). This effect describes the opposite resonance effect between the electron-attracting boron atom and the electron-donating nitrogen atom, thereby achieving the alternating separation of the HOMO-LUMO orbital distribution within the rigid aromatic framework. This structural design effectively reduces the energy gap (ΔE) between the singlet and triplet states. ST), thus achieving excellent TADF performance. In its synthesis process, carbon-nitrogen coupling and carbon-sulfur coupling reactions play a key role, and molecules with different structures are constructed through these coupling reactions, thereby achieving excellent optical properties.

[0005] At present, many TADF molecular precursors have been successfully prepared by various synthetic methods, especially the design strategies based on nitrogen heterocycles, sulfur heterocycles and aromatic compounds. In 2016, Hatakeyama's group first reported the new design of ultrapure blue fluorescent organic molecules based on thermally activated delayed fluorescence (MR-TADF) with multiple resonance effect. Without introducing additional donor and acceptor groups, 1-bromo-2,3-dichlorobenzene and diphenylamine compounds were coupled by Pd-catalyzed CN coupling reaction, and nitrogen atoms were introduced into the molecules. Subsequently, the final products DABNA-1 and DABNA-2 were obtained by "one-pot" borylation reaction (Hatakeyama T, Shiren K, Nakajima K, et al. Ultrapure Blue Thermally Activated Delayed Fluorescence Molecules: Efficient HOMO-LUMO Separation by the Multiple Resonance Effect [J]. Advanced. Mater. 2016, 28 (14): 2777-2781). In 2019, Duan et al. optimized the structure of DABNA-1, replaced diphenylamine with carbazole, and introduced peripheral electron-donating and electron-withdrawing groups to design the BNCz framework and a series of compounds based on the BNCz framework. The synthetic route still refers to DABNA-1, using the Hartwig-Buchwald amination reaction to construct a nitrogen-containing monobromine precursor, followed by borylation with lithium reagents and BBr, and finally completing the ring closure reaction by forming a CB bond through an intramolecular alkylation reaction (Zhang Y, Zhang D, Wei J, et al. Multi-Resonance Induced Thermally Activated Delayed Fluorophores for NarrowbandGreen OLEDs[J]. Angew Chem Int Ed Engl, 2019, 58(47): 16912~16917).In 2023, Wang et al. used carbazole and aniline compounds to synthesize TADF molecular precursors. During the synthesis process, a series of nitrogen-containing heterocyclic precursors were constructed using transition metal-catalyzed carbon-nitrogen coupling reactions. Finally, the final molecule m-DBCz with TADF performance was obtained through a "one-pot" borylation reaction (Cai X, Pu Y, Li C, et al. Multi-Resonance Building-Block-Based Electroluminescent Material: Lengthening Emission Maximum and Shortening Delayed Fluorescence Lifetime [J]. Angew Chem Int Ed Engl, 2023, 62 (27): e202304104). In these synthetic processes, carbon-nitrogen coupling and carbon-sulfur coupling reactions also played an important role. Through these reactions, a variety of molecular structures were constructed, thereby significantly improving the optical properties and device efficiency of the material. These advances provide a solid theoretical and experimental basis for the further optimization and application of TADF materials. Summary of the invention

[0006] The object of the present invention is to provide three key bromine-containing intermediates for synthesizing TADF molecules and their synthesis methods.

[0007] The technical solution for achieving the purpose of the present invention is as follows:

[0008] The key bromine-containing intermediate in the synthesis of TADF molecules is N 1 -(3-(bis(4-(tert-butyl)phenyl)amino)-2-bromo-5-(tert-butyl)phenyl)-2-bromo-5-(tert-butyl)-N-(3-(bis(4-(tert-butyl)phenyl)amino)-2-bromo-5-(tert-butyl)phenyl) 1 ,N 3 ,N 3 -Tris(4-(tert-butyl)phenyl)benzene-1,3-diamine (N 1 -(3-(bis(4-(tert-butyl)phenyl)amino)-2-bromo-5-(tert-butyl)phenyl)-2-bromo-5-(tert-butyl)-N 1 ,N 3 ,N 3 -tris(4-(tert-butyl)phenyl)benzene-1,3-diamine, KBI-1), 2-bromo-N 1- (2-Bromo-5-(tert-butyl)-3-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl)-5-(tert-butyl)-N 1 ,N3 ,N 3 -Tris(4-(tert-butyl)phenyl)benzene-1,3-diamine (2-bromo-N 1 -(2-bromo-5-(tert-butyl)-3-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl)-5-(tert-butyl)-N 1 ,N 3 ,N 3 -tris(4-(tert-butyl)phenyl)benzene-1,3-diamine, KBI-2) or 2-bromo-N-(2-bromo-5-(tert-butyl)-3-((4-(tert-butyl)phenyl)thio)phenyl)-5-(tert-butyl)-N-(4-(tert-butyl)phenyl)-3-(3,6-di-tert-butyl-9H-carbazol-9-yl)aniline (2-bromo-N-(2-bromo-5-(tert-butyl)-3-((4-(tert-butyl)phenyl)thio)phenyl)-5-(tert-butyl)-N-(4-(tert-butyl)phenyl)-3-(3,6-di-tert-butyl-9H-carbazol-9-yl)aniline, KBI-3), the structural formula of which is as follows:

[0009]

[0010] The synthesis method of the key bromine-containing intermediate KBI-1 for synthesizing the above TADF molecule is as follows:

[0011]

[0012] The specific steps include:

[0013] (1) Using toluene as a reaction solvent, 2-bromo-5-(tert-butyl)-1,3-diiodobenzene (Compound 1a) and di(4-tert-butylphenyl)amine undergo a carbon-nitrogen coupling reaction at 100°C to 150°C in the presence of a catalyst of palladium acetate, a ligand of 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene and sodium tert-butoxide to prepare 2-bromo-5-(tert-butyl)-N,N-bis(4-(tert-butyl)phenyl)-3-iodoaniline (Compound 1b);

[0014] (2) Using toluene as the reaction solvent, compound 1b and 4-tert-butylaniline were subjected to a carbon-nitrogen coupling reaction at 100°C to 150°C in the presence of a catalyst of palladium acetate, a ligand of 1,1'-binaphthyl-2,2'-bis(diphenylphosphine) and sodium tert-butoxide to prepare 2-bromo-5-(tert-butyl)-N-( ... 1 ,N 1 ,N 3 -tri(4-(tert-butyl)phenyl)benzene-1,3-diamine (2-bromo-5-(tert-butyl)-N 1 ,N 1 ,N 3 -tris(4-(tert-butyl)phenyl)benzene-1,3-diamine, compound 1c);

[0015] (3) Using toluene as the reaction solvent, compound 1b and compound 1c under the presence of a catalyst of palladium acetate, a ligand of tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide undergo a carbon-nitrogen coupling reaction at 100° C. to 150° C. to prepare compound KBI-1.

[0016] Preferably, in step (1), the molar ratio of di(4-tert-butylphenyl)amine, compound 1a, catalyst palladium acetate, ligand 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene, and sodium tert-butoxide is 1:1.2:0.1:0.3:4; and the reaction time is 9 to 12 hours.

[0017] Preferably, in step (2), the molar ratio of compound 1b, 4-tert-butylaniline, catalyst palladium acetate, ligand 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, and sodium tert-butoxide is 1:1.2:0.1:0.3:4; and the reaction time is 2 to 5 hours.

[0018] Preferably, in step (3), the molar ratio of compound 1c, compound 1b, catalyst palladium acetate, ligand tri-tert-butylphosphine tetrafluoroborate, and sodium tert-butoxide is 1:1:0.1:0.3:4; and the reaction time is 9 to 12 hours.

[0019] The synthesis method of the key bromine-containing intermediate KBI-2 for synthesizing the above TADF molecule is as follows:

[0020]

[0021] The specific steps include:

[0022] (1) Using toluene as a reaction solvent, compound 1a and di(4-tert-butylphenyl)amine are reacted in the presence of a catalyst of palladium acetate, a ligand of 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene and sodium tert-butoxide to undergo a carbon-nitrogen coupling reaction at 100° C. to 150° C. to prepare compound 1b;

[0023] (2) Using toluene as the reaction solvent, 2-bromo-5-(tert-butyl)-N-(4-(tert-butyl)phenyl)-3-(3,6-di-tert-butyl-9H-carbazol-9-yl)aniline (Compound 2b) and Compound 1b undergo carbon-nitrogen coupling reaction at 100°C to 150°C in the presence of a catalyst of palladium acetate, a ligand of tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide to prepare Compound KBI-2.

[0024] Preferably, in step (2), the molar ratio of compound 2b, compound 1b, catalyst palladium acetate, ligand tri-tert-butylphosphine tetrafluoroborate, and sodium tert-butoxide is 1:1:0.1:0.3:4; and the reaction time is 9 to 12 hours.

[0025] The synthesis method of the key bromine-containing intermediate KBI-3 for synthesizing the above TADF molecule is as follows:

[0026]

[0027] The specific steps include:

[0028] (1) Using toluene as a reaction solvent, compound 1a and 4-tert-butylbenzenethiol undergo a carbon-sulfur coupling reaction at 100° C. to 150° C. in the presence of a catalyst of palladium acetate, a ligand of bis(2-diphenylphosphophenyl)ether and potassium tert-butoxide to prepare 2-bromo-5-(tert-butyl)-3-iodophenyl)(4-(tert-butyl)phenyl)sulfane (compound 3a);

[0029] (2) Using toluene as the reaction solvent, compound 2b and compound 3a under the presence of a catalyst of palladium acetate, a ligand of tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide, undergo a carbon-nitrogen coupling reaction at 100° C. to 150° C. to prepare compound KBI-3.

[0030] Preferably, in step (1), the molar ratio of 4-tert-butylbenzenethiol, compound 1a, catalyst palladium acetate, ligand bis(2-diphenylphosphinophenyl) ether, and potassium tert-butoxide is 1:1:0.01:0.02:4; and the reaction time is 2 to 6 hours.

[0031] Preferably, in step (2), the molar ratio of compound 2b, compound 3a, catalyst palladium acetate, ligand tri-tert-butylphosphine tetrafluoroborate, and sodium tert-butoxide is 1:1:0.1:0.3:6; and the reaction time is 9 to 12 hours.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] (1) The present invention realizes the selective mono-substitution control of carbon-nitrogen coupling and carbon-sulfur coupling reactions through ligand screening, successfully solving the key problem in the synthesis of such symmetrical molecules. And by precisely controlling the ligand, the intermediate of the target product is successfully synthesized and further converted into the final product.

[0034] (2) The three key bromine-containing intermediates synthesized by the present invention serve as TADF molecular precursors centered on a double boron atom, each with unique structural characteristics and potential. Among them, KBI-1 has a symmetrical structure, and the key intermediate in its synthesis route is constructed by a ligand-controlled selective monosubstituted carbon-nitrogen coupling reaction. The resulting product contains two functional groups, a bromine atom and an iodine atom, which facilitates subsequent conversion reactions and has great application potential in fields such as medicine. KBI-2 is further synthesized and derived on the basis of KBI-1, has unique structural characteristics, and shows potential application value. Through a carbon-sulfur coupling reaction, the present invention successfully synthesized KBI-3, and its key intermediate is also constructed by a ligand-controlled selective monosubstituted carbon-sulfur coupling reaction. As a sulfur-doped TADF molecular precursor, KBI-3 forms a new molecular structure, providing new ideas for subsequent molecular design. The compounds KBI-1, KBI-2 and KBI-3 of the present invention can be used to prepare molecules with TADF properties through a "one-pot" borylation reaction, which involves step-by-step reactions: ① a lithiation reaction of a carbon-halogen bond assisted by a tert-butyl lithium reagent; ② a transmetallation reaction performed by boron tribromide; and ③ an intramolecular borylation reaction involving 1,2,2,6,6-pentamethylpiperidine. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is the H NMR spectrum of compound 1a of Example 1;

[0036] Figure 2 is the H NMR spectrum of compound 1b of Example 1;

[0037] Figure 3 is the NMR carbon spectrum of compound 1b of Example 1;

[0038] Figure 4 is the H NMR spectrum of compound 1c of Example 1;

[0039] Figure 5 is the NMR carbon spectrum of compound 1c of Example 1;

[0040] Figure 6 This is the H NMR spectrum of the product KBI-1 of Example 1;

[0041] Figure 7 is the NMR carbon spectrum of the product KBI-1 of Example 1;

[0042] Figure 8 is the H NMR spectrum of compound 2a of Example 2;

[0043] Fig. 9 is the H NMR spectrum of compound 2b of Example 2;

[0044] Fig.10 This is the H NMR spectrum of the product KBI-2 of Example 2;

[0045] Fig.11 is the NMR carbon spectrum of the product KBI-2 of Example 2;

[0046] Fig.12 is the H NMR spectrum of compound 3a of Example 3;

[0047] Fig.13 is the NMR carbon spectrum of compound 3a of Example 3;

[0048] Fig.14 This is the H NMR spectrum of the product KBI-3 of Example 3;

[0049] Fig.15 This is the NMR carbon spectrum of the product KBI-3 of Example 3. DETAILED DESCRIPTION

[0050] The present invention is further described in detail below with reference to specific embodiments.

[0051] In the following examples, compound 1a was prepared according to the reference [Cai X, Pu Y, Li C, et al. Multi-Resonance Building-Block-Based Electroluminescent Material: Lengthening Emission Maximum and Shortening Delayed Fluorescence Lifetime [J]. Angew Chem Int Ed Engl, 2023, 62(27): e202304104], and the synthetic route was: Specifically, iodine (2.0 equiv, 10 mmol) and silver sulfate (2.0 equiv, 10 mmol) were added to a 100 mL round-bottom flask containing a magnetic stirrer of appropriate size, and then ethanol (30 mL) was added. Then, 4-tert-butylaniline (1.0 equiv, 5 mmol) was slowly dripped into the mixture in an ice-water bath at 0°C and stirred at room temperature. The reaction progress was monitored by TLC until the reaction was complete. After the reaction was completed, the mixture was filtered through diatomaceous earth and the solvent was concentrated under vacuum. The concentrated product was dissolved in dichloromethane and washed twice with aqueous sodium hydroxide solution, then washed once with water, and then washed once with saturated brine. After drying over anhydrous sodium sulfate, the solvent was removed by vacuum concentration again. Then, the crude product was dissolved in petroleum ether and impurities were removed by short silica gel column chromatography. Finally, the crude product was concentrated under reduced pressure to obtain the crude product. The crude product was dissolved in 30 mL of acetonitrile and cooled to 0°C in an ice-water bath. Subsequently, hydrobromic acid aqueous solution (48% in water, 1.32 equiv, 5 mmol) was slowly added to the reaction flask, and sodium nitrite aqueous solution (1.14 equiv, 5.37 mmol) was continued to be slowly added. The reaction system was maintained at 0°C. After the addition was completed, the temperature was raised to 50°C and cuprous bromide (0.25 equiv, 1.25 mmol) was added. The mixture was stirred at 50°C for 3-4 hours. After the reaction was completed, the solvent was concentrated under vacuum. Then, dichloromethane was used for extraction, and the extract was dried over anhydrous sodium sulfate and concentrated to remove the solvent. Finally, the crude product was dissolved in petroleum ether, and impurities were removed by short silica gel column chromatography. Finally, petroleum ether was used for recrystallization to obtain a red solid product compound 1a, and the total separation yield of the two steps was 46%.

[0052] Compound 1a: 1 H NMR(500MHz,Chloroform-d)δ1.26(9H,s),7.82(2H,s).

[0053] Compound 2b was prepared according to the reference [Cai X, Pu Y, Li C, et al. Multi-Resonance Building-Block-Based Electroluminescent Material: Lengthening Emission Maximum and Shortening Delayed Fluorescence Lifetime [J]. Angew Chem Int Ed Engl, 2023, 62(27): e202304104], and the synthetic route is:

[0054]

[0055] Specifically:

[0056] (1) Take a dry 25 mL pressure tube, add a magnetic stirrer, and then add compound 1a (0.1 mmol, 1.0 equiv), 3,6-di-tert-butylcarbazole (0.12 mmol, 1.2 equiv), cuprous oxide (0.02 mmol, 20 mmol%), potassium carbonate (2.0 mmol, 2.0 eq), and DMF (1 mL) to the reaction tube in sequence. Then, replace the nitrogen, seal the tube with a polytetrafluoroethylene lid, and heat the reaction solution to 150°C for 24 hours. After the reaction was completed, the reaction mixture was cooled to room temperature and extracted with EA / PE. The organic phase was collected and concentrated by rotary evaporation. The concentrate was purified by silica gel column chromatography using DCM / PE as eluent to obtain the target product 9-(2-bromo-5-(tert-butyl)-3-iodophenyl)-3,6-di-tert-butyl-9H-carbazole (Compound 2a) with an isolated yield of 52%.

[0057] Compound 2a: 1 H NMR(500MHz,Chloroform-d)δ8.15(d,J=1.9Hz,2H),8.03(d,J=2.3Hz,1H),7.45(dd,J=8 .6, 1.9Hz, 2H), 7.43 (d, J = 2.3Hz, 1H), 6.98 (d, J = 8.5Hz, 2H), 1.47 (s, 19H), 1.31 (s, 9H).

[0058] (2) Take a dry 25 mL pressure tube, add a magnetic stirrer, and then add compound 2a (0.1 mmol, 1.0 equiv), 4-tert-butylaniline (0.117 mmol, 1.17 equiv), palladium acetate (0.007 mmol, 7 mmol%), Dppf (0.014 mmol, 14 mmol%), sodium tert-butoxide (3.5 mmol, 3.5 eq), toluene (1 mL) to the reaction tube, then replace nitrogen, seal with a polytetrafluoroethylene lid, and heat the reaction solution to 110 ° C for 2 hours. After the reaction is completed, the reaction mixture is cooled to room temperature, the diatomaceous earth is rinsed with DCM to filter out the insoluble matter, the washing liquid is collected, and the concentrated liquid is concentrated by rotary evaporation. The concentrate is purified by silica gel column chromatography using DCM / PE as the eluent to obtain the target product compound 2b with an isolated yield of 79%.

[0059] Compound 2b: 1H NMR(500MHz,Chloroform-d)δ8.17(d,J=1.4Hz,2H),7.47-7.46(m,J=7.5Hz,3H),7.42(d,J=8.5Hz,2H),7. 22(d,J=8.5Hz,2H),7.09(d,J=8.6Hz,2H),6.96(d,J=2.1Hz,1H),1.49(s,18H),1.38(s,9H),1.29(s,9H).

[0060] Example 1

[0061] The synthesis of compound KBI-1, the synthetic route is:

[0062]

[0063] The following steps are involved:

[0064] (1) Take a dry 25 mL pressure tube, add a magnetic stirrer, then add di(4-tert-butylphenyl)amine (0.1 mmol, 1.0 equiv), 1a (0.12 mmol, 1.2 equiv), palladium acetate (0.01 mmol, 10 mmol%), XantPhos (0.03 mmol, 30 mmol%), sodium tert-butoxide (4.0 mmol, 4.0 eq), toluene (1 mL) to the reaction tube, then replace nitrogen, seal with a polytetrafluoroethylene lid, heat the reaction solution to 110 ° C for 12 hours. After the reaction is completed, the reaction mixture is cooled to room temperature, the diatomaceous earth is rinsed with DCM to filter out the insoluble matter, the washing liquid is collected, and the concentrated liquid is concentrated by rotary evaporation. The concentrate is purified by silica gel column chromatography using DCM / PE as the eluent to obtain the target product compound 1b with a yield of 68%.

[0065] Compound 1b: 1 H NMR (500MHz, Chloroform-d) δ7.77(d,J=2.3Hz,1H),7.25(d,J=2.3Hz,1H),7.24-7.21(m,4H),6.90-6.86(m,4H),1.31(s,18H),1.24(s,9H). 13 C NMR(126MHz,Chloroform-d)δ153.56,145.95,144.55,144.05,135.34,129.28, 128.65,125.84,121.06,103.64,34.67,34.26,31.55,31.13.HRMS(ESI-TOF)m / z calcd forC 30 H 38 BrN+ [M+H + ]:618.12783,found:618.12783.

[0066] (2) Take a dry 25 mL pressure tube, add a magnetic stirrer, then add 4-tert-butylaniline (0.12 mmol, 1.2 equiv), compound 1b (0.1 mmol, 1.0 equiv), palladium acetate (0.01 mmol, 10 mmol%), BINAP (0.03 mmol, 30 mmol%), sodium tert-butoxide (3.0 mmol, 4.0 eq), toluene (1 mL) to the reaction tube, then replace nitrogen, seal with a polytetrafluoroethylene lid, heat the reaction solution to 110 ° C for 3 hours. After the reaction is completed, the reaction mixture is cooled to room temperature, the diatomaceous earth is rinsed with DCM to filter out the insoluble matter, the washing liquid is collected, and the concentrated liquid is concentrated by rotary evaporation. The concentrate is purified by silica gel column chromatography using DCM / PE as the eluent to obtain the target product compound 1c with a yield of 70%.

[0067] Compound 1c: 1 H NMR(500MHz,Chloroform-d)δ7.37-7.33(m,2H),7.24(d,J=2.3Hz,1H),7.24-7.21(m,4H),7.14-7.10( m,2H),6.98-6.92(m,4H),6.82(d,J=2.2Hz,1H),6.16(s,1H),1.34(s,9H),1.30(s,18H),1.22(s,9H). 13 C NMR(126MHz,Chloroform-d)δ152.06,145.66,145.30,144.31,144.02,142.71,139.36,126.29,125 .67,120.79,120.07,119.50,111.07,110.63,34.85,34.34,34.19,31.52,31.22.HRMS(ESI-TOF)m / z calcd forC 41 H 51 Bn 2 + [M+H + ]:639.32783,found:639.32783.

[0068] (3) Take a dry 25 mL pressure tube, add a magnetic stirrer, and then add 1b (0.1 mmol, 1.0 equiv), compound 1c (0.1 mmol, 1.0 equiv), palladium acetate (0.01 mmol, 10 mmol%), tri-tert-butylphosphine tetrafluoroborate (0.03 mmol, 30 mmol%), sodium tert-butoxide (4.0 mmol, 4.0 eq), toluene (1 mL) to the reaction tube, then replace nitrogen, seal with a polytetrafluoroethylene lid, and heat the reaction solution to 110 ° C for 12 hours. After the reaction is completed, the reaction mixture is cooled to room temperature, the diatomaceous earth is rinsed with DCM to filter out the insoluble matter, the washing liquid is collected, and the concentrated liquid is concentrated by rotary evaporation. The concentrate is purified by silica gel column chromatography using DCM / PE as the eluent to obtain the target product KBI-1 with a yield of 63%.

[0069] KBI-1: 1 H NMR(500MHz,Chloroform-d)δ7.19(d,J=8.6Hz,8H),7.15(d,J=8.7Hz,2H),

[0070] 7.09(s,4H),6.89(d,J=8.5Hz,8H),6.61(d,J=8.7Hz,2H),1.29(s,36H),1.26(s,9H),1.17(s,18H). 13 C NMR(126MHz,Chloroform-d)δ152.38,147.53,146.89,144.53,144.28,143.91,143.69,125.64,125.50 ,125.41,124.12,121.83,120.57,119.50,34.69,34.17,34.10,31.50,31.47,31.10.HRMS(ESI-TOF)m / z calcd for C 70 H 88 Br 2 N 3 + [M+H + ]:1128.53783,found:1128.53783.

[0071] Example 2

[0072] The synthesis of compound KBI-2, the synthetic route is:

[0073]

[0074] The following steps are involved:

[0075] Take a dry 25mL pressure tube with a support, add a magnetic stirrer, and then add compound 1b (0.1mmol, 1.0equiv), compound 2b (0.1mmol, 1.0equiv), palladium acetate (0.01mmol, 10mmol%), Dppf (0.03mmol, 30mmol%), sodium tert-butoxide (4mmol, 4.0eq), toluene (1mL) to the reaction tube in sequence, then replace nitrogen, seal with a polytetrafluoroethylene lid, and heat the reaction solution to 110°C for 12 hours. After the reaction is completed, the reaction is cooled to room temperature, the diatomaceous earth is rinsed with DCM to filter out the insoluble matter, the washing liquid is collected, and the concentrated liquid is concentrated by rotary evaporation. The concentrate is purified by silica gel column chromatography using DCM / PE as the eluent to obtain the target product KBI-2 with a yield of 60%.

[0076] KBI-2: 1 H NMR (500MHz, CDCl3) δ8.16 (d, J=1.6Hz, 2H), 7.45 (dd, J=8.5Hz, 2H), 7.29

[0077] (d,J=6.2Hz,2H),7.27(s,1H),7.24-7.21(m,6H),7.16(d,J=2.5Hz,1H),6.99(d,J=8.5Hz,2H),6.97-6.91(m,4H),6 .79(dd,J=7.2Hz,2H),1.48(d,J=2.1Hz,18H),1.32(d,J=2.1Hz,9H),1.31(d,J=1.8Hz,18H),1.24(d,J=2.2Hz,18H). 13 C NMR(126MHz,Chloroform-d)δ152.50,152.38,147.89,144.28,144.01,142.51,139.40,138.66,125.93,125.69,124.39,123.97 ,123.51,123.09,120.80,120.62,120.50,120.21,116.31,109.56,34.78,34.19,32.12,31.51,31.13,31.11.HRMS(ESI-TOF)m / z calcd for C70H86Br2N3+[M+H+]:1126.51783, found:1126.51783.

[0078] Example 3

[0079] The synthesis of compound KBI-3, the synthetic route is:

[0080]

[0081] The following steps are involved:

[0082] (1) Take a dry 25 mL pressure tube, add a magnetic stirrer, and then add compound 1a (0.1 mmol, 1.0 equiv), 4-tert-butylbenzenethiol (0.1 mmol, 1.0 equiv), palladium acetate (0.001 mmol, 1 mmol%), DPEphos (0.002 mmol, 2 mmol%), potassium tert-butoxide (4 mmol, 4.0 eq), and toluene (1 mL) to the reaction tube in sequence, then replace nitrogen, seal with a polytetrafluoroethylene lid, and heat the reaction solution to 110° C. for 5 hours. After the reaction is completed, the reaction mixture is cooled to room temperature, the diatomaceous earth is rinsed with DCM to filter out the insoluble matter, the washing liquid is collected, and concentrated by rotary evaporation. The concentrate is purified by silica gel column chromatography using DCM / PE as the eluent to obtain the target product compound 3a with a yield of 60%.

[0083] Compound 3a: 1 H NMR (500MHz, Chloroform-d) δ7.61(d,J=2.0Hz,1H),7.44(qd,J=8.5,1.9Hz,4H),6.66(d,J=1.9Hz,1H),1.34(d,J=1.8Hz,9H),1.07(d,J=1.7Hz,9H). 13 CNMR(126MHz,Chloroform-d)δ152.65,152.10,141.16,134.46,134.32,129.44, 126.86,125.63,124.81,102.76,34.86,34.56,31.26,30.77.HRMS(ESI-TOF)m / z calcd forC 20 H 25 BIS + [M+H + ]:502.98783,found:502.98783.

[0084] (2) Take a dry 25 mL pressure tube with a support, add a magnetic stirrer, and then add compound 2b (0.1 mmol, 1.0 equiv), compound 3a (0.1 mmol, 1.0 equiv), palladium acetate (0.01 mmol, 10 mmol%), P( t Bu) 3 ·HBF 4 (0.03mmol, 30mmol%), tBuONa (6mmol, 6.0eq), toluene (1mL), then replace nitrogen, seal with a polytetrafluoroethylene lid, heat the reaction solution to 110°C for 12 hours. After the reaction is completed, cool the reaction to room temperature, rinse the diatomaceous earth with DCM to filter out insoluble matter, collect the washings, and concentrate by rotary evaporation. The concentrate is purified by silica gel column chromatography using DCM / PE as the eluent to obtain the target product KBI-3 with a yield of 70%.

[0085] KBI-3: 1 H NMR(500MHz,Chloroform-d)δ8.14(d,J=1.9Hz,2H),7.46-7.39(m,6H),7.33

[0086] (d,J=2.4Hz,1H),7.27-7.25(m,3H),7.05(d,J=2.2Hz,1H),6.97(d,J=8.6Hz,2H),6.77-6.71(m ,2H),6.69(d,J=2.2Hz,1H),1.46(s,18H),1.34(s,9H),1.31(s,9H),1.23(s,9H),1.09(s,9H). 13 C NMR(126MHz,Chloroform-d)δ152.51,151.28,147.45,146.10,144.69,144.3 2,142.55,141.03,139.36,138.70,133.49,126.59,126.49,125.73,124.28,1 24.13,123.48,123.14,120.51,119.99,119.61,116.34,109.51,34.88,34.7 6,34.69,34.21,32.09,31.50,31.28,31.08,30.85,29.74.HRMS(ESI-TOF)m / z calcd forC 60 H 73 Br 2 N 2 S + [M+H + ]:1011.38783,found:1011.38783.

[0087] Comparative Example 1

[0088] The synthesis of compound 1b in this comparative example is basically the same as that in Example 1, except that triphenylphosphine, tributylphosphine, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, and 1,1'-bis(diphenylphosphino)ferrocene are used as phosphine ligands, and only disubstituted products can be obtained.

[0089] It can be seen from this that the monosubstituted product compound 1b is obtained only when the 4,5-bisdiphenylphosphino-9,9-dimethylxanthene of the present invention is used.

[0090] Comparative Example 2

[0091] The synthesis of compound 3a in this comparative example is basically the same as that in Example 1, except that triphenylphosphine, tributylphosphine, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, and 1,1'-bis(diphenylphosphino)ferrocene are used as phosphine ligands, respectively. It is found that the target product compound 3a can be obtained only when bis(2-diphenylphosphinophenyl) ether is used as the ligand.

[0092] Comparative Example 3

[0093] The syntheses of KBI-1 in this comparative example are basically the same as those in Example 1, KBI-2 in Example 2, and KBI-3 in Example 3, except that the ligand tri-tert-butylphosphine tetrafluoroborate is replaced by triphenylphosphine, tributylphosphine, 1,1'-bis(diphenylphosphino)ferrocene, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, and 4,5-bisdiphenylphosphine-9,9-dimethyloxanthene, respectively. It is found that the target product can be synthesized only when tri-tert-butylphosphine tetrafluoroborate is used as the ligand.

Claims

1. A key bromine-containing intermediate for synthesizing TADF molecules, characterized in that: It is KBI-1, KBI-2 or KBI-3, and its structural formula is as follows: 。 2. The method for synthesizing the key bromine-containing intermediate for synthesizing TADF molecules according to claim 1, characterized in that: The specific steps of KBI-1 synthesis are as follows: (1) Using toluene as the reaction solvent, 2-bromo-5-(tert-butyl)-1,3-diiodobenzene and di(4-tert-butylphenyl)amine were subjected to a carbon-nitrogen coupling reaction at 100°C to 150°C in the presence of a catalyst of palladium acetate, a ligand of 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene and sodium tert-butoxide to prepare 2-bromo-5-(tert-butyl)- N,N -Bis(4-(tert-butyl)phenyl)-3-iodoaniline; (2) Toluene was used as the reaction solvent, 2-bromo-5-(tert-butyl)- N,N -bis(4-(tert-butyl)phenyl)-3-iodoaniline and 4-tert-butylaniline were reacted in the presence of palladium acetate catalyst, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine ligand and sodium tert-butoxide at 100℃~150℃ to prepare 2-bromo-5-(tert-butyl)- N 1 , N 1 , N 3 -tri(4-(tert-butyl)phenyl)benzene-1,3-diamine; (3) Toluene was used as the reaction solvent, 2-bromo-5-(tert-butyl)- N,N -bis(4-(tert-butyl)phenyl)-3-iodoaniline and 2-bromo-5-(tert-butyl)- N 1 , N 1 , N 3 -Tri(4-(tert-butyl)phenyl)benzene-1,3-diamine undergoes carbon-nitrogen coupling reaction in the presence of catalyst palladium acetate, ligand tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide at 100° C.~150° C. to prepare compound KBI-1.

3. The synthesis method according to claim 2, characterized in that In step (2), 2-bromo-5-(tert-butyl)- N,N The molar ratio of bis(4-(tert-butyl)phenyl)-3-iodoaniline and 4-tert-butylaniline in the catalyst palladium acetate, the ligand 1,1'-binaphthyl-2,2'-bisdiphenylphosphine and sodium tert-butoxide is 1:1.2:0.1:0.3:4; the reaction time is 2 to 5 hours.

4. The synthesis method according to claim 2, characterized in that In step (3), 2-bromo-5-(tert-butyl)- N 1 , N 1 , N 3 -Tris(4-(tert-butyl)phenyl)benzene-1,3-diamine, 2-bromo-5-(tert-butyl)- N,N The molar ratio of bis(4-(tert-butyl)phenyl)-3-iodoaniline, catalyst palladium acetate, ligand tri-tert-butylphosphine tetrafluoroborate, and sodium tert-butoxide is 1:1:0.1:0.3:4; and the reaction time is 9 to 12 hours.

5. The method for synthesizing the key bromine-containing intermediate for synthesizing TADF molecules according to claim 1, characterized in that: The specific steps of KBI-2 synthesis are as follows: (1) Using toluene as the reaction solvent, 2-bromo-5-(tert-butyl)-1,3-diiodobenzene and di(4-tert-butylphenyl)amine were subjected to a carbon-nitrogen coupling reaction at 100°C to 150°C in the presence of a catalyst of palladium acetate, a ligand of 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene and sodium tert-butoxide to prepare 2-bromo-5-(tert-butyl)- N,N -Bis(4-(tert-butyl)phenyl)-3-iodoaniline; (2) Toluene was used as the reaction solvent, 2-bromo-5-(tert-butyl)- N -(4-(tert-butyl)phenyl)-3-(3,6-di-tert-butyl-9 H -carbazol-9-yl)aniline and 2-bromo-5-(tert-butyl)- N,N -Bis(4-(tert-butyl)phenyl)-3-iodoaniline undergoes carbon-nitrogen coupling reaction in the presence of catalyst palladium acetate, ligand tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide at 100° C. to 150° C. to prepare compound KBI-2.

6. The synthesis method according to claim 2 or 5, characterized in that: In step (1), the molar ratio of di(4-tert-butylphenyl)amine, 2-bromo-5-(tert-butyl)-1,3-diiodobenzene, catalyst palladium acetate, ligand 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene, and sodium tert-butoxide is 1:1.2:0.1:0.3:4; and the reaction time is 9 to 12 hours.

7. The synthesis method according to claim 5, characterized in that In step (2), 2-bromo-5-(tert-butyl)- N -(4-(tert-butyl)phenyl)-3-(3,6-di-tert-butyl-9 H -carbazol-9-yl)aniline, 2-bromo-5-(tert-butyl)- N,N The molar ratio of bis(4-(tert-butyl)phenyl)-3-iodoaniline, catalyst palladium acetate, ligand tri-tert-butylphosphine tetrafluoroborate, and sodium tert-butoxide is 1:1:0.1:0.3:4; and the reaction time is 9 to 12 hours.

8. The method for synthesizing the key bromine-containing intermediate for synthesizing TADF molecules according to claim 1, characterized in that: The specific steps of KBI-3 synthesis are as follows: (1) Using toluene as a reaction solvent, 2-bromo-5-(tert-butyl)-1,3-diiodobenzene and 4-tert-butylbenzenethiol undergo a carbon-sulfur coupling reaction at 100°C to 150°C in the presence of a catalyst, palladium acetate, a ligand, bis(2-diphenylphosphinophenyl) ether, and potassium tert-butoxide to prepare 2-bromo-5-(tert-butyl)-3-iodophenyl)(4-(tert-butyl)phenyl)sulfane; (2) Toluene was used as the reaction solvent, 2-bromo-5-(tert-butyl)- N -(4-(tert-butyl)phenyl)-3-(3,6-di-tert-butyl-9 H Compound KBI-3 was prepared by carbon-nitrogen coupling reaction of 2-bromo-5-(tert-butyl)-3-iodophenyl)(4-(tert-butyl)phenyl)sulfane with 2-bromo-5-(tert-butyl)-3-iodophenyl)(4-(tert-butyl)phenyl)sulfane in the presence of palladium acetate as a catalyst, tri-tert-butylphosphine tetrafluoroborate as a ligand and sodium tert-butoxide at 100°C~150°C.

9. The synthesis method according to claim 8, characterized in that In step (1), the molar ratio of 4-tert-butylbenzenethiol, 2-bromo-5-(tert-butyl)-1,3-diiodobenzene, catalyst palladium acetate, ligand bis(2-diphenylphosphinophenyl)ether, and potassium tert-butoxide is 1:1:0.01:0.02:4; and the reaction time is 2 to 6 hours.

10. The synthesis method according to claim 2, characterized in that: In step (2), 2-bromo-5-(tert-butyl)- N -(4-(tert-butyl)phenyl)-3-(3,6-di-tert-butyl-9 H The molar ratio of 2-bromo-5-(tert-butyl)-3-iodophenyl)(4-(tert-butyl)phenyl)sulfane, catalyst palladium acetate, ligand tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide is 1:1:0.1:0.3:6; the reaction time is 9 to 12 hours.

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