Triaryl substituted ethylene compound and synthesis method thereof

Abstract

According to the method, 0.2 mmol of benzoxazole and 1.5 equivalent weight of 2-(1-phenyl vinyl) benzoic acid are used as reaction raw materials, 7.5 mol% of Pd (OAc) 2 is used as a catalyst, 1.5 equivalent weight of BoC2O, 1.5 equivalent weight of sodium hydrogen sulfite and cyclohexane are used as solvents, the raw materials are heated to 130 DEG C in a nitrogen atmosphere, an effective reaction is performed for 16 h, and the triaryl substituted ethylene compound is obtained. And the triaryl substituted ethylene compound is obtained with high yield. The method has the advantages of high yield, simplicity and convenience in operation, low cost, no pollution and the like, and has certain feasibility for realizing industrial production.

Description

Technical Field

[0001] The present invention belongs to the field of transition metal-catalyzed organic synthesis, and specifically relates to a method for synthesizing triaryl-substituted ethylene compounds.

Background Art

[0002] Triaryl ethylene (TAE) is an important class of organic molecular skeletons containing a large π-conjugated structure. This unique structure makes it play an important role in related fields such as optoelectronic materials and medicinal chemistry. Polymerizable aggregation-induced emission multi-substituted triaryl ethylene can be used for the preparation of fluorescent materials, such as photochromic materials and organic light-emitting diodes. With the wide application of TAE skeleton molecules in various fields, studying efficient methods for synthesizing TEA is a very meaningful research work. Therefore, the synthesis of triaryl-substituted ethylene compounds has always been the focus of attention of scientific researchers.

[0003] Currently, the methods commonly used for synthesizing the TAE skeleton mainly include the McMurry coupling reaction, that is, the condensation and deoxygenation of two carbonyl groups of aryl aldehydes and aryl ketones under the action of reducing metals and low-valent titanium to obtain triaryl ethylene, or the coupling of aryl halides with olefins to synthesize the TAE skeleton, and the configuration of the ethylene product is regulated by different types of olefins. However, these chemical reactions usually require harsh reaction conditions, the raw materials are sensitive to water and air, unstable and highly toxic, and at the same time produce stoichiometric by-products, with low atom utilization rate and serious pollution.

[0004] Olefin compounds are widely present in nature, are cheap and easily available, and have low toxicity. They are widely used as ideal raw materials in organic synthesis. In 2020, the Lin Guoqiang research group of the Shanghai Institute of Organic Chemistry reported the migratory coupling reaction of 2-alkenyl bromobenzene and aryl boronic acid esters. Through the strategy of 1,4-palladium migration, after activating the alkenyl C–H bond, a Suzuki-Miyaura coupling reaction occurs to prepare a series of triaryl ethylene compounds with high configurational selectivity, and the configurations of multiple single crystals determine the products. This reaction uses palladium acetate as a catalyst, large steric hindrance (2-MeO-Ph) 3 P as a ligand, and cesium pivalate as a base. Heating to 110 °C in tetrahydrofuran and reacting for 3 h can obtain the target product with high to moderate yields. However, this method uses toxic organic halides as raw materials and is more sensitive to air and water. Therefore, we have invented a method for synthesizing triaryl-substituted ethylene compounds, which uses 2-(1-phenylethenyl)benzoic acid and benzoxazole compounds as raw materials, and synthesizes triaryl-substituted ethylene compounds through palladium acetate catalysis. This method requires no special equipment, is simple to operate, has high yields, a wide range of applications, and has certain industrial application value.

Summary of the Invention

[0005] The object of the present invention is to provide a method for highly efficiently and selectively synthesizing the TAE skeleton by using palladium acetate as a catalyst, a carboxylic acid compound and a heterocyclic aromatic hydrocarbon as raw materials, and activating the C–H of the intramolecular olefin through a 1,4-palladium migration strategy of an arylpalladium intermediate and then coupling with one molecule of aromatic hydrocarbon. This method has the advantages of simple operation, few additives, and high yield, and has a certain feasibility for realizing its industrial production.

[0006] To achieve the above object of the invention, the following technical solutions are proposed:

[0007] A triaryl-substituted ethylene compound and a synthesis method thereof, wherein the general structural formula of the triaryl-substituted ethylene compound I is as follows:

[0008]

[0009] wherein the Ar 3 is benzoxazole, 6-methylbenzoxazole, 5-fluorobenzoxazole, 5-chlorobenzoxazole, methyl 7-benzoxazolecarboxylate, 7-acetylbenzoxazole, ethyl 5-oxazolecarboxylate. The synthesis method of the compound I is characterized in that a carboxylic acid compound II and a heterocyclic aromatic hydrocarbon III are used as raw materials, cyclohexane is used as a solvent, 7.5 mol% of copper acetate is used as a catalyst, and the reaction is effectively carried out at 130 °C for 16 h to obtain the triaryl-substituted ethylene compound I in high yield.

[0010] In the above synthesis method, the structural formulas of the raw material carboxylic acid compound II and the heterocyclic aromatic hydrocarbon III are as follows:

[0011]

[0012] wherein the Ar 3 is benzoxazole, 6-methylbenzoxazole, 5-fluorobenzoxazole, 5-chlorobenzoxazole, methyl 7-benzoxazolecarboxylate, 7-acetylbenzoxazole, ethyl 5-oxazolecarboxylate.

[0013] In the above synthesis method, the palladium catalyst is 7.5 mol%, cyclohexane is used as a solvent, the reaction time is 16 h, and the reaction temperature is 130 °C.

[0014] The synthesis method of a class of triaryl-substituted ethylene compounds provided by the present invention is a green and efficient synthesis route, and its advantages are: high yield of the target product, wide substrate applicability, simple reaction operation, and green and pollution-free by-products.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 is a route diagram for preparing the triaryl-substituted ethylene compound provided by the present invention.

DETAILED DESCRIPTION

[0016] A triaryl-substituted ethylene compound provided by the present invention and its synthesis method. Please refer to the attached drawings: Using a carboxylic acid compound and a heteroaromatic compound as raw materials, cyclohexane as a solvent, 7.5 mol% palladium acetate as a catalyst, placed in a reaction vessel, heated to 130 °C under a nitrogen atmosphere, and reacted for 16 hours. After the reaction is completed, the corresponding target product is obtained by column chromatography separation and purification.

[0017] The following further illustrates the present invention with specific preparation examples:

[0018] Preparation Example 1

[0019] Add 0.2 mmol of benzoxazole and 0.3 mmol of 2-(1-phenylethenyl)benzoic acid to a 25 mL tubular reactor, add Pd(OAc) 2 7.5 mol%, dppp 15 mol%, CuBr 15 mol%, NaHSO 3 0.3 mmol, 2 mL of cyclohexane, heated to 130 °C and reacted for 16 h under a nitrogen atmosphere. After the reaction is completed, the product is separated and purified by column chromatography, and the separation yield is 85%. 1 HNMR(400MHz,Chloroform-d)δ7.72–7.67(m,1H),7.54–7.47(m,2H),7.47–7.43(m,3H),7.43–7.39(m,3H),7.37–7.33(m,2H),7.31–7.28(m,1H),7.28–7.20(m,2H),7.09(s,1H). 13 CNMR(101MHz,Chloroform-d)δ162.3,152.4,150.0,141.6,141.3,138.9,129.8,129.1,128.4,128.2,128.2,127.9,127.2,124.9,124.2,119.7,113.1,110.2.

[0020] Preparation Example 2

[0021] Add 0.2 mmol of 6-methylbenzoxazole and 0.3 mmol of 2-(1-phenylethenyl)benzoic acid to a 25 mL tubular reactor, add Pd(OAc) 2 7.5 mol%, dppp 15 mol%, CuBr 15 mol%, NaHSO 3 0.3 mmol, 2 mL of cyclohexane, heated to 130 °C and reacted for 16 h under a nitrogen atmosphere. After the reaction is completed, the product is separated and purified by column chromatography, and the separation yield is 79%.1 1H NMR (400 MHz, Chloroform-d) δ 7.53 (d, J = 8.1 Hz, 1H), 7.44 (d, J = 3.1 Hz, 2H), 7.42–7.40 (m, 2H), 7.39 (d, J = 3.3 Hz, 2H), 7.38–7.35 (m, 2H), 7.31 (dd, J = 7.8, 1.9 Hz, 2H), 7.09 (d, J = 8.1 Hz, 1H), 7.03 (s, 1H), 6.99 (s, 1H), 2.42 (d, J = 5.4 Hz, 3H). 13 13C NMR (101 MHz, Chloroform-d) δ 161.9, 151.8, 150.3, 141.3, 139.4, 139.1, 135.6, 129.8, 129.1, 128.2, 127.9, 125.6, 119.1, 113.2, 110.4.

[0022] Preparation Example 3

[0023] Add 0.2 mmol of 5-fluorobenzoxazole and 0.3 mmol of 2-(1-phenylethenyl)benzoic acid to a 25 mL tubular reactor, add Pd(OAc) 2 7.5 mol%, dppp 15 mol%, CuBr 15 mol%, NaHSO 3 0.3 mmol, 2 mL of cyclohexane, and under a nitrogen atmosphere, heat to 130 °C and react for 16 h. After the reaction is completed, the product is separated and purified by column chromatography, and the separation yield is 85%. 1 1H NMR (400 MHz, Chloroform-d) δ 7.47–7.42 (m, 2H), 7.42 (d, J = 4.1 Hz, 1H), 7.40 (d, J = 4.6 Hz, 2H), 7.39–7.35 (m, 3H), 7.31 (ddt, J = 7.9, 6.4, 2.3 Hz, 3H), 7.11 (dd, J = 8.9, 4.3 Hz, 1H), 7.02 (s, 1H), 6.95 (td, J = 9.1, 2.6 Hz, 1H). 13 13C NMR (101 MHz, Chloroform-d) δ 163.9, 161.1, 158.7, 153.1, 146.3, 142.5, 142.3, 141.1, 138.8, 129.8, 129.3, 128.4, 128.4, 128.2, 128.0, 112.7, 112.4, 110.5, 110.4, 106.1, 105.9.

[0024] Preparation Example 4

[0025] Add 0.2 mmol of 5-chlorobenzoxazole and 0.3 mmol of 2-(1-phenylethenyl)benzoic acid to a 25 mL tubular reactor. Add Pd(OAc) 2 7.5 mol%, dppp 15 mol%, CuBr 15 mol%, NaHSO 3 0.3 mmol, 2 mL of cyclohexane. Under a nitrogen atmosphere, heat to 130 °C and react for 16 h. After the reaction is completed, the product is separated and purified by column chromatography, and the separation yield is 82%. 1 H NMR (400 MHz, Chloroform-d) δ 7.54 (d, J = 2.0 Hz, 1H), 7.38–7.33 (m, 3H), 7.31 (s, 4H), 7.22 (t, J = 1.7 Hz, 1H), 7.20 (d, J = 2.0 Hz, 1H), 7.19 (s, 1H), 7.12 (dd, J = 8.6, 2.0 Hz, 1H), 7.03 (d, J = 8.6 Hz, 1H), 6.93 (s, 1H). 13 C NMR (101 MHz, Chloroform-d) δ 129.8, 129.4, 128.5, 128.4, 128.3, 128.1, 125.2, 119.7, 112.6, 111.0, 77.2, 76.9, 76.6, 1.0.

[0026] Preparation Example 5

[0027] Add 0.2 mmol of methyl 7-benzoxazolecarboxylate and 0.3 mmol of 2-(1-phenylethenyl)benzoic acid to a 25 mL tubular reactor. Add Pd(OAc) 2 7.5 mol%, dppp 15 mol%, CuBr 15 mol%, NaHSO 3 0.3 mmol, 2 mL of cyclohexane. Under a nitrogen atmosphere, heat to 130 °C and react for 16 h. After the reaction is completed, the product is separated and purified by column chromatography, and the separation yield is 83%. 1 H NMR (400 MHz, Chloroform-d) δ 7.95 (d, J = 7.8 Hz, 1H), 7.87 (d, J = 7.3 Hz, 1H), 7.50–7.44 (m, 3H), 7.41 (d, J = 5.5 Hz, 5H), 7.40–7.37 (m, 2H), 7.37–7.35 (m, 1H), 7.09 (s, 1H), 3.77 (s, 3H). 1313C NMR (101 MHz, Chloroform-d) δ 164.8, 163.2, 153.6, 148.7, 143.1, 141.5, 138.9, 130.1, 129.4, 128.5, 128.4, 128.1, 127.4, 124.5, 124.1, 114.6, 112.6, 52.2.

[0028] Preparation Example 6

[0029] 0.2 mmol of 7-acetylbenzoxazole and 0.3 mmol of 2-(1-phenylethenyl)benzoic acid were added to a 25 mL tubular reactor, along with 7.5 mol% of Pd(OAc) 2 15 mol% of dppp, 15 mol% of CuBr, 0.3 mmol of NaHSO 3 and 2 mL of cyclohexane. The reaction was heated to 130 °C under a nitrogen atmosphere for 16 h. After the reaction, the product was separated and purified by column chromatography, with a separation yield of 71%. 1 1H NMR (400 MHz, Chloroform-d) δ 7.89 (td, J = 7.9, 1.2 Hz, 2H), 7.46 (dt, J = 4.7, 2.9 Hz, 3H), 7.40 (q, J = 3.0 Hz, 6H), 7.37–7.33 (m, 2H), 7.15 (s, 1H), 2.01 (s, 3H). 13 13C NMR (101 MHz, Chloroform-d) δ 194.9, 162.6, 153.3, 148.9, 142.7, 140.9, 139.4, 129.6, 129.5, 128.5, 128.5, 128.5, 128.2, 125.3, 124.6, 124.4, 121.3, 112.5, 29.9.

[0030] Preparation Example 7

[0031] 0.2 mmol of naphthooxazole and 0.3 mmol of 2-(1-phenylethenyl)benzoic acid were added to a 25 mL tubular reactor, along with 7.5 mol% of Pd(OAc) 2 15 mol% of dppp, 15 mol% of CuBr, 0.3 mmol of NaHSO 3 and 2 mL of cyclohexane. The reaction was heated to 130 °C under a nitrogen atmosphere for 16 h. After the reaction, the product was separated and purified by column chromatography, with a separation yield of 70%. 1HNMR(400MHz, Chloroform-d) δ 8.10 (s, 1H), 7.97–7.93 (m, 1H), 7.86–7.81 (m, 1H), 7.56 (s, 1H), 7.53–7.45 (m, 3H), 7.45–7.42 (m, 4H), 7.41–7.38 (m, 3H), 7.37–7.33 (m, 2H), 7.11 (s, 1H). 13 C NMR(101MHz, Chloroform-d) δ 164.4, 154.0, 149.1, 141.6, 141.2, 138.9, 131.7, 131.3, 129.9, 129.4, 128.5, 128.4, 128.4, 128.0, 127.7, 125.3, 124.5, 116.9, 112.9, 105.9.

[0032] Preparation Example 8

[0033] 0.2 mmol of ethyl 5-oxazolecarboxylate and 0.3 mmol of 2-(1-phenylethenyl)benzoic acid were added to a 25 mL tubular reactor. Pd(OAc) 2 7.5 mol%, dppp 15 mol%, CuBr 15 mol%, NaHSO 3 0.3 mmol, 2 mL of cyclohexane were added. Under a nitrogen atmosphere, the mixture was heated to 130 °C and reacted for 16 h. After the reaction, the product was separated and purified by column chromatography, and the separation yield was 63%. 1 H NMR(400MHz, Chloroform-d) δ 7.70 (s, 1H), 7.46 (dd, J = 5.0, 1.8 Hz, 3H), 7.39 (s, 5H), 7.31–7.29 (m, 2H), 6.97 (s, 1H), 4.30 (q, J = 7.1 Hz, 2H), 1.34 (t, J = 7.1 Hz, 3H). 13 C NMR(101MHz, Chloroform-d) δ 163.2, 157.6, 152.5, 141.2, 140.9, 138.5, 135.0, 129.5, 129.3, 128.4, 128.4, 128.2, 128.1, 111.9, 61.1, 14.1.

[0034] Preparation Example 9

[0035] 0.2 mmol of 5-phenyloxazole and 0.3 mmol of 2-(1-phenylethenyl)benzoic acid were added to a 25 mL tubular reactor. Pd(OAc) 27.5 mol%, dppp 15 mol%, CuBr 15 mol%, NaHSO 3 0.3 mmol, 2 mL of cyclohexane, under a nitrogen atmosphere, heated to 130 °C and reacted for 16 h. After the reaction, the product was separated and purified by column chromatography, and the separation yield was 88%. 1 H NMR (400 MHz, Chloroform-d) δ 7.52 (dd, J = 5.0, 1.9 Hz, 3H), 7.46–7.43 (m, 2H), 7.40–7.37 (m, 4H), 7.36 (d, J = 2.9 Hz, 2H), 7.32 (d, J = 5.2 Hz, 1H), 7.30–7.26 (m, 2H), 7.15–7.12 (m, 2H), 7.05 (s, 1H). 13 C NMR (101 MHz, Chloroform-d) δ 160.4, 150.4, 148.3, 141.0, 139.8, 129.4, 128.7, 128.6, 128.4, 128.4, 128.1, 127.7, 127.6, 123.9, 123.1, 112.9.

[0036] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the appended claims.

Claims

1. A triaryl-substituted ethylene compound and a method for synthesizing the same, wherein the general structural formula of the triaryl-substituted ethylene compound I is as follows: Among them, Ar 3 The synthesis method of compound I is characterized by: Using carboxylic acid compounds as raw materials, cyclohexane as solvent, and 7.5 mol% palladium acetate as catalyst, the reaction was effectively carried out at 130°C in a nitrogen environment for 16 hours to obtain triaryl substituted vinyl compound I in high yield.

2. The synthesis method according to claim 1, characterized in that The structural formula of heterocyclic aromatic hydrocarbon compound III is as follows: Among them, Ar 3 It is benzoxazole, 6-methylbenzoxazole, 5-fluorobenzoxazole, 5-chlorobenzoxazole, 7-benzoxazolecarboxylic acid methyl ester, 7-acetylbenzoxazole, and 5-oxazolecarboxylic acid ethyl ester.

3. The synthesis method according to claim 1, characterized in that In a nitrogen atmosphere, the catalyst was 7.5 mol%, cyclohexane was used as the solvent; the reaction time was 16 h, and the reaction temperature was 130°C.

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