Synthesis of an intermediate for benzofuran-based organic light-emitting materials

Abstract

This invention relates to the field of organic chemistry, specifically disclosing a synthesis method for intermediates of benzofuran-based organic light-emitting materials. Compared with existing technologies, this invention features milder reaction conditions, higher atom utilization, reduced use of precious metal catalysts in the synthesis reaction, and broadens the synthesis pathways for organic light-emitting materials. Compared with existing technologies, it uses different starting materials to synthesize organic light-emitting materials with CAS numbers 2701590-36-3, 2786655-30-7, and 2676940-58-0, optimizes the synthesis pathways of multiple organic light-emitting materials, reduces the production cost per unit of organic matter, increases the selectivity of the synthesis route, and provides more substrate options to control synthesis costs.

Description

Technical Field

[0001] This invention relates to the field of organic chemistry, and specifically discloses the synthesis of an intermediate for benzofuran-based organic light-emitting materials. Background Technology

[0002] Benzofuran compounds, as important intermediates, have been proposed in several patents for use in the synthesis of organic light-emitting materials, such as DE102021126547, WO2021150092, and CN 113121556 A.

[0003] For example, CN 113121556 A is used to synthesize the luminescent material A24, with the specific route as follows:

[0004]

[0005] For example, in DE102021126547, the specific route for synthesizing luminescent material 77 is as follows:

[0006]

[0007] CN 113121556 A requires a high dose of the precious metal palladium catalyst, while DE102021126547 involves cumbersome steps, requiring multiple chromatographic purifications of the crude product, resulting in a low final yield and driving up the unit cost of production. Summary of the Invention

[0008] To address the problems existing in the prior art, the first aspect of this invention proposes a method for synthesizing a benzofuran compound derivative of formula C, as follows:

[0009] Compound B is dissolved in an organic solvent, and then one of tricyclohexylphosphine tetrafluoroborate or tri-tert-butylphosphine tetrafluoroborate is added. The mixture is then reacted with a base and a palladium salt under an inert atmosphere to obtain compound C.

[0010] .

[0011] In some specific embodiments of the first aspect of the present invention, the amount of compound B in each 1L of organic solvent is 251~302 mmol; in some specific embodiments of the first aspect of the present invention, the amount of compound B in each 1L of organic solvent is 251 mmol; in some specific embodiments of the first aspect of the present invention, the amount of compound B in each 1L of organic solvent is 260 mmol; and in some specific embodiments of the first aspect of the present invention, the amount of compound B in each 1L of organic solvent is 302 mmol.

[0012] In some specific embodiments of the first aspect of the present invention, the amount of palladium acetate in each 1L of organic solvent is 4.76~6.05 mmol; in some specific embodiments of the first aspect of the present invention, the amount of palladium acetate in each 1L of organic solvent is 5.05 mmol; in some specific embodiments of the first aspect of the present invention, the amount of palladium acetate in each 1L of organic solvent is 5.60 mmol; and in some specific embodiments of the first aspect of the present invention, the amount of palladium acetate in each 1L of organic solvent is 5.80 mmol.

[0013] In some specific embodiments of the first aspect of the present invention, the amount of either tri-tert-butylphosphine tetrafluoroborate or tricyclohexylphosphine tetrafluoroborate in each 1L of the organic solvent is 8.63~12.1 mmol; in some specific embodiments of the first aspect of the present invention, the amount of either tri-tert-butylphosphine tetrafluoroborate or tricyclohexylphosphine tetrafluoroborate in each 1L of the organic solvent is 9.0 mmol; in some specific embodiments of the first aspect of the present invention, the amount of either tri-tert-butylphosphine tetrafluoroborate or tricyclohexylphosphine tetrafluoroborate in each 1L of the organic solvent is 9.5 mmol; and in some specific embodiments of the first aspect of the present invention, the amount of either tri-tert-butylphosphine tetrafluoroborate or tricyclohexylphosphine tetrafluoroborate in each 1L of the organic solvent is 11.0 mmol.

[0014] In some specific embodiments of the first aspect of the present invention, the amount of alkali added per 1L of the organic solvent is 503~604 mmol; in some specific embodiments of the first aspect of the present invention, the amount of alkali added per 1L of the organic solvent is 530 mmol; in some specific embodiments of the first aspect of the present invention, the amount of alkali added per 1L of the organic solvent is 545 mmol; in some specific embodiments of the first aspect of the present invention, the amount of alkali added per 1L of the organic solvent is 570 mmol; and in some specific embodiments of the first aspect of the present invention, the amount of alkali added per 1L of the organic solvent is 600 mmol.

[0015] In some specific embodiments of the first aspect of the present invention, the molar ratio of compound B to palladium acetate is (25.1~27.2):(0.502~0.545), and in some specific embodiments of the first aspect of the present invention, the molar ratio of compound B to palladium acetate is (25~26):0.5.

[0016] In some specific embodiments of the first aspect of the present invention, the molar ratio of one of the tri-tert-butylphosphine tetrafluoroborate or tricyclohexylphosphine tetrafluoroborate to the alkali is (0.8~1.2):(40~60). In some specific embodiments of the first aspect of the present invention, the molar ratio of one of the tri-tert-butylphosphine tetrafluoroborate or tricyclohexylphosphine tetrafluoroborate to the alkali is (1.0~1.1):(50~55).

[0017] In some specific embodiments of the first aspect of the present invention, the alkali is selected from one or a mixture of potassium tert-butoxide, sodium tert-butoxide, cesium carbonate, and sodium carbonate.

[0018] In some specific embodiments of the first aspect of the present invention, the inert atmosphere is one or a mixture of nitrogen atmosphere, argon atmosphere, or a mixture thereof.

[0019] In some specific embodiments of the first aspect of the present invention, the reaction temperature is 110~150°C; in some specific embodiments of the first aspect of the present invention, the reaction temperature is 120~140°C; and in some specific embodiments of the first aspect of the present invention, the reaction temperature is 130°C.

[0020] A second aspect of this invention provides a method for synthesizing a benzofuran compound derivative of formula B, as follows:

[0021] Compound A, compound Aa, cyclohexanediamine, cuprous iodide and potassium phosphate were added to an organic solvent and reacted under an inert atmosphere to obtain compound B.

[0022] .

[0023] In some specific embodiments of the second aspect of the present invention, the molar amount of compound A in each 1L of the organic solvent is 401~457 mmol; in some specific embodiments of the second aspect of the present invention, the molar amount of compound A in each 1L of the organic solvent is 410 mmol; in some specific embodiments of the second aspect of the present invention, the molar amount of compound A in each 1L of the organic solvent is 420 mmol; in some specific embodiments of the second aspect of the present invention, the molar amount of compound A in each 1L of the organic solvent is 430 mmol; and in some specific embodiments of the second aspect of the present invention, the molar amount of compound A in each 1L of the organic solvent is 440 mmol.

[0024] In some specific embodiments of the second aspect of the present invention, the molar amount of compound Aa in each 1L of the organic solvent is 604~686 mmol; in some specific embodiments of the second aspect of the present invention, the molar amount of compound Aa in each 1L of the organic solvent is 615 mmol; in some specific embodiments of the second aspect of the present invention, the molar amount of compound Aa in each 1L of the organic solvent is 630 mmol; and in some specific embodiments of the second aspect of the present invention, the molar amount of compound Aa in each 1L of the organic solvent is 650 mmol.

[0025] In some specific embodiments of the second aspect of the present invention, the molar amount of cyclohexanediamine in each 1L of the organic solvent is 16.1~18.3 mmol, 17.0 mmol, 17.5 mmol, or 18.0 mmol.

[0026] In some specific embodiments of the second aspect of the present invention, the molar amount of cuprous iodide in each 1L of the organic solvent is 8.19~9.9 mmol; in some specific embodiments of the second aspect of the present invention, the molar amount of cuprous iodide in each 1L of the organic solvent is 8.3 mmol; and in some specific embodiments of the second aspect of the present invention, the molar amount of cuprous iodide in each 1L of the organic solvent is 9.5 mmol.

[0027] In some specific embodiments of the second aspect of the present invention, the molar amount of potassium phosphate in each 1L of the organic solvent is 860~914 mmol; in some specific embodiments of the second aspect of the present invention, the molar amount of potassium phosphate in each 1L of the organic solvent is 890 mmol; and in some specific embodiments of the second aspect of the present invention, the molar amount of potassium phosphate in each 1L of the organic solvent is 910 mmol.

[0028] In some specific embodiments of the second aspect of the present invention, the molar ratio of compound A to compound Aa is (80.1~96.1):(120.8~144.2), and in some specific embodiments of the second aspect of the present invention, the molar ratio of compound A to compound Aa is 90:130.

[0029] In some specific embodiments of the second aspect of the present invention, the molar ratio of cyclohexanediamine to cuprous iodide is (3.22~3.84):(1.61~1.98), and in some specific embodiments of the second aspect of the present invention, the molar ratio of cyclohexanediamine to cuprous iodide is 3.5:1.7.

[0030] In some specific embodiments of the second aspect of the present invention, the molar ratio of compound A to potassium phosphate is (80.1~96.1):(172~192), and in some specific embodiments of the second aspect of the present invention, the molar ratio of compound A to potassium phosphate is 90:180.

[0031] In some specific embodiments of the second aspect of the present invention, the organic solvent is selected from one or a mixture of DMF, acetonitrile, alcohols, and dichloromethane.

[0032] In some specific embodiments of the second aspect of the present invention, the inert atmosphere is one or a mixture of argon and nitrogen.

[0033] In some specific embodiments of the second aspect of the present invention, the reaction temperature is 100~140°C; in some specific embodiments of the second aspect of the present invention, the reaction temperature is 100°C; in some specific embodiments of the second aspect of the present invention, the reaction temperature is 120°C; and in some specific embodiments of the second aspect of the present invention, the reaction temperature is 140°C.

[0034] The third aspect of this invention relates to the application of the compound shown in Formula C in the preparation of organic light-emitting materials.

[0035] The third aspect proposes the application of the compound shown in Formula II in the preparation of organic light-emitting materials.

[0036] The reagents used in this invention are purchased from the open market, such as Maclean's reagents, Sinopharm Chemical reagents, Xilong Chemical reagents, and Sigma Chemical reagents. The reagents added to the reaction system in the synthesis steps have a purity level of AR or higher, and the reagents used for analysis and testing have a purity level of GR or HPLC or higher, and have not undergone further purification.

[0037] “w / w” represents the mass fraction, and “ND” indicates that it is below the detection limit.

[0038] In this invention, "room temperature" refers to a temperature from about 10°C to about 40°C. In some embodiments, "room temperature" refers to a temperature from about 20°C to about 30°C; in other embodiments, "room temperature" refers to °C, 22.5°C, 25°C, 27.5°C, etc.

[0039] The yield formula of this invention is:

[0040] Unless otherwise specified, all experimental operations in this invention are performed under standard atmospheric pressure.

[0041] Advantages of this invention:

[0042] This invention relates to the field of organic chemistry, specifically disclosing a synthesis method for intermediates of benzofuran-based organic light-emitting materials. Compared with existing technologies, this invention features milder reaction conditions, higher atom utilization, reduced use of precious metal catalysts in the synthesis reaction, and broadens the synthesis pathways for organic light-emitting materials. Compared with existing technologies, it uses different reaction starters to synthesize organic light-emitting materials with CAS numbers 2701590-36-3, 2786655-30-7, and 2676940-58-0, optimizing the synthesis pathways of multiple organic light-emitting materials, reducing preparation costs, and broadening selectivity. Attached Figure Description

[0043] Figure 1 This shows the 1H NMR data of compound C of the present invention; Detailed Implementation

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0045] The synthetic route of this invention can be summarized as follows:

[0046]

[0047] S1: Add compound A and compound Aa to an organic solvent, then add cyclohexanediamine, cuprous iodide and potassium phosphate, replace with an inert gas, stir and heat, use TLC to measure the reaction of the raw materials, and then return to room temperature.

[0048] Water was added to the reaction solution, followed by extraction with ethyl acetate. The organic phase was washed three times with water, dried over anhydrous sodium sulfate, and concentrated by silica gel column chromatography to obtain a crude product. This crude product was then crystallized from ethyl acetate and petroleum ether to obtain compound B.

[0049] S2: Compound B was dissolved in an organic solvent, and palladium acetate, tri-tert-butylphosphine tetrafluoroborate, and sodium tert-butoxide were added. The mixture was purged with an inert gas, stirred, heated, and refluxed. TLC showed the reaction was complete. Water was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic phase was washed three times with water, dried over anhydrous sodium sulfate, and concentrated by silica gel column chromatography to obtain a crude product. Compound C was then crystallized from toluene.

[0050] The process is described below through specific implementation:

[0051] Example 1:

[0052]

[0053] Compound A (91.5 mmol) and compound Aa (137.2 mmol) were added to DMF (200 mL), followed by cyclohexanediamine (3.66 mmol), cuprous iodide (1.83 mmol), and potassium phosphate (180 mmol). The mixture was purged with nitrogen three times. The mixture was stirred and heated to 120 °C. TLC showed that the reactants had largely reacted to completion. The mixture was then cooled to room temperature. Water was added to the reaction mixture, and the solution was extracted with ethyl acetate. The organic phase was washed three times with water, dried over anhydrous sodium sulfate, and concentrated by silica gel column chromatography to obtain a crude product. This crude product was then crystallized from ethyl acetate and petroleum ether to give compound B (81.3% yield).

[0054]

[0055] Compound B (26.8 mmol) was dissolved in xylene (100 mL), and palladium acetate (0.505 mmol), tri-tert-butylphosphine tetrafluoroborate (1.01 mmol), and sodium tert-butoxide (53.6 mmol) were added. The mixture was purged with nitrogen three times. The mixture was stirred and heated to reflux at 130 °C. TLC showed that the reaction was complete. Water was added to the reaction mixture, and the solution was extracted with ethyl acetate. The organic phase was washed three times with water, dried over anhydrous sodium sulfate, and concentrated by silica gel column chromatography to obtain the crude product. The crude product was then crystallized from toluene to give compound C (yield 85.1%).

[0056] 1 H NMR (400 MHz, Chloroform-d) δ 8.42 (dd, J = 7.8, 1.3 Hz, 1H), 8.29 (dd, J = 7.3, 1.3 Hz, 1H), 7.74 - 7.69 (m, 1H), 7.66 - 7.61 (m, 1H), 7.59 (s,1H), 7.54-7.51 (m, 2H), 7.48-7.42 (m, 2H).

[0057] Example 2:

[0058] Compound A (80.5 mmol) and compound Aa (120.8 mmol) were added to DMF (200 mL), followed by cyclohexanediamine (3.22 mmol), cuprous iodide (1.61 mmol), and potassium phosphate (172 mmol). The mixture was purged with nitrogen three times. The mixture was stirred and heated to 130 °C. TLC showed that the reactants had largely reacted to completion. The mixture was then cooled to room temperature. Water was added to the reaction mixture, followed by extraction with ethyl acetate. The organic phase was washed three times with water, dried over anhydrous sodium sulfate, and concentrated using a silica gel column to obtain a crude product. This crude product was then crystallized from ethyl acetate and petroleum ether to give compound B (75.2% yield).

[0059] Compound B (27.2 mmol) was dissolved in xylene (90 mL), and palladium acetate (0.545 mmol), tri-tert-butylphosphine tetrafluoroborate (1.09 mmol), and potassium tert-butoxide (54.4 mmol) were added. The mixture was purged with nitrogen three times. The mixture was stirred and heated to reflux at 140 °C. TLC showed that the reaction was complete. Water was added to the reaction mixture, and the solution was extracted with ethyl acetate. The organic phase was washed three times with water, dried over anhydrous sodium sulfate, and concentrated by silica gel column chromatography to obtain the crude product. The crude product was then crystallized from toluene to give compound C (77.3% yield).

[0060] 1 H NMR (400 MHz, Chloroform-d) δ 8.42 (dd, J = 7.8, 1.3 Hz, 1H), 8.29 (dd, J = 7.3, 1.3 Hz, 1H), 7.74 - 7.69 (m, 1H), 7.66 - 7.61 (m, 1H), 7.59 (s,1H), 7.54-7.51 (m, 2H), 7.48-7.42 (m, 2H).

[0061] Example 3:

[0062] Compound A (96.1 mmol) and compound Aa (144.2 mmol) were added to DMF (210 mL), followed by cyclohexanediamine (3.84 mmol), cuprous iodide (1.92 mmol), and potassium phosphate (172 mmol). The mixture was purged with nitrogen three times. The mixture was stirred and heated to 110 °C. TLC showed that the reactants had largely reacted to completion. The mixture was then cooled to room temperature. Water was added to the reaction mixture, followed by extraction with ethyl acetate. The organic phase was washed three times with water, dried over anhydrous sodium sulfate, and concentrated using a silica gel column to obtain a crude product. This crude product was then crystallized from ethyl acetate and petroleum ether to give compound B (76.9% yield).

[0063] Compound B (26.2 mmol) was dissolved in xylene (110 mL), and palladium acetate (0.524 mmol), tri-tert-butylphosphine tetrafluoroborate (0.95 mmol), and sodium tert-butoxide (55.4 mmol) were added. The mixture was purged with nitrogen three times. The mixture was stirred and heated to reflux at 120 °C. TLC showed that the reaction was complete. Water was added to the reaction mixture, and the solution was extracted with ethyl acetate. The organic phase was washed three times with water, dried over anhydrous sodium sulfate, and concentrated by silica gel column chromatography to obtain the crude product. The crude product was then crystallized from toluene to give compound C (yield 81.5%).

[0064] 1H NMR (400 MHz, Chloroform-d) δ 8.42 (dd, J = 7.8, 1.3 Hz, 1H), 8.29 (dd, J = 7.3, 1.3 Hz, 1H), 7.74 - 7.69 (m, 1H), 7.66 - 7.61 (m, 1H), 7.59 (s,1H), 7.54-7.51 (m, 2H), 7.48-7.42 (m, 2H).

[0065] Example 4:

[0066] Compound A (80.1 mmol) and compound Aa (137.0 mmol) were added to NMP (200 mL), followed by cyclohexanediamine (3.27 mmol), cuprous iodide (1.98 mmol), and potassium phosphate (172 mmol). The mixture was purged with nitrogen three times. The mixture was stirred and heated to 120 °C. TLC showed that the reactants had largely reacted to completion. The mixture was then cooled to room temperature. Water was added to the reaction mixture, followed by extraction with ethyl acetate. The organic phase was washed three times with water, dried over anhydrous sodium sulfate, and concentrated using a silica gel column to obtain a crude product. This crude product was then crystallized from ethyl acetate and petroleum ether to give compound B (82.9% yield).

[0067] Compound B (25.1 mmol) was dissolved in xylene (100 mL), and palladium acetate (0.502 mmol), tricyclohexylphosphine tetrafluoroborate (1.12 mmol), and sodium tert-butoxide (50.2 mmol) were added. The mixture was purged with nitrogen three times. The mixture was stirred and heated to reflux at 130 °C. TLC showed that the reaction was complete. Water was added to the reaction mixture, and the solution was extracted with ethyl acetate. The organic phase was washed three times with water, dried over anhydrous sodium sulfate, and concentrated by silica gel column chromatography to obtain the crude product. The crude product was then crystallized from toluene to give compound C (71.7% yield).

[0068] 1 H NMR (400 MHz, Chloroform-d) δ 8.42 (dd, J = 7.8, 1.3 Hz, 1H), 8.29 (dd, J = 7.3, 1.3 Hz, 1H), 7.74 - 7.69 (m, 1H), 7.66 - 7.61 (m, 1H), 7.59 (s,1H), 7.54-7.51 (m, 2H), 7.48-7.42 (m, 2H).

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for synthesizing a benzofuran compound derivative of formula C, as follows: Compound A, compound Aa, cyclohexanediamine, cuprous iodide and potassium phosphate were added to a first organic solvent and reacted under an inert atmosphere at a first reaction temperature to obtain compound B. ； Compound B was dissolved in a second organic solvent, and then tricyclohexylphosphine tetrafluoroborate was added. The mixture was reacted with a base and a palladium salt under an inert atmosphere and at a second reaction temperature to obtain compound C. ； The palladium salt is palladium acetate; The alkali is selected from potassium tert-butoxide, sodium tert-butoxide, or a mixture thereof.

2. The method for synthesizing compound C according to claim 1, characterized in that, The amount of compound B added per 1L of the second organic solvent is 251~302 mmol, and the amount of compound A added per 1L of the first organic solvent is 401~457 mmol.

3. The method for synthesizing compound C according to claim 1, characterized in that, The amount of palladium acetate added per 1L of the second organic solvent is 4.76~6.05mmol.

4. The method for synthesizing compound C according to claim 1, characterized in that, The amount of tricyclohexylphosphine tetrafluoroborate added per 1L of the second organic solvent is 8.63~12.1mmol.

5. The method for synthesizing compound C according to claim 1, characterized in that, The amount of alkali added per 1L of the second organic solvent is 503~604mmol.

6. The method for synthesizing compound C according to claim 1, characterized in that, The molar ratio of compound B to palladium salt is (25.1~27.2):(0.502~0.545).

7. The method for synthesizing compound C according to claim 1, characterized in that, The inert atmosphere is one of nitrogen atmosphere, argon atmosphere, or a mixture thereof.

8. The method for synthesizing compound C according to claim 1, characterized in that, The second reaction temperature is 130~140℃, the first reaction temperature is 100~140℃, the molar amount of compound Aa in 1L of the first organic solvent is 604~686 mmol, the molar amount of cyclohexanediamine in 1L of the first organic solvent is 16.1~18.3 mmol, the molar amount of cuprous iodide in 1L of the first organic solvent is 8.19~9.9 mmol, and the molar amount of potassium phosphate in 1L of the first organic solvent is 86 mmol. The concentration is 0~914 mmol, the molar ratio of compound A to compound Aa is (80.1~96.1):(120.8~144.2), the molar ratio of cyclohexanediamine to cuprous iodide is (3.22~3.84):(1.61~1.98), the molar ratio of compound A to potassium phosphate is (80.1~96.1):(172~192), and the first organic solvent is selected from one or a mixture of DMF, acetonitrile, NMP, alcohols, and dichloromethane.

Images