Catalytic system and method for synthesizing diarylacetylene from calcium carbide and aryl iodide

Abstract

The invention relates to a catalytic system and method for synthesizing diarylacetylene from calcium carbide and aryl iodide. The invention relates to a catalytic system for synthesizing diarylacetylene from calcium carbide and aryl iodide. The catalytic system comprises a DBU ionic liquid, an organic solvent and a palladium catalyst. The invention also discloses a method for synthesizing diarylacetylene from calcium carbide and aryl iodide. According to the catalytic system and method for synthesizing the diarylacetylene from the calcium carbide and the aryl iodide, the DBU salt participates in the reaction for synthesizing the diarylacetylene from the calcium carbide and the aryl iodide, so that the reaction safety can be improved while the catalytic system is simplified on the premise of ensuring the catalytic effect.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a catalytic system and method for synthesizing diarylacetylene from calcium carbide and iodinated aromatic hydrocarbons. Background Art

[0002] Diarylacetylene contains unsaturated carbon-carbon triple bonds and can be used as organic intermediates for the synthesis of drugs, bioactive molecules, new materials, and optoelectronic materials. The synthesis method of diarylacetylene is: under transition metal catalysis, aromatic halides and terminal alkynes are cross-coupled to synthesize diarylacetylene. Since the reaction operation is simple, the reaction yield is high, and it is an atom-economical reaction, the Sonogashira coupling is the main tool for the synthesis of diarylacetylene. The traditional Sonogashira reaction involving calcium carbide uses palladium as a catalyst, triphenylphosphine as a ligand, and copper as a co-catalyst. Under alkaline conditions, aryl halides and calcium carbide are cross-coupled to obtain diarylacetylene.

[0003] As the reaction progresses, although the reaction has achieved great success, it still requires triphenylphosphine as a ligand and cuprous iodide as a co-catalyst. Among them, triphenylphosphine is easily oxidized in the air, and cuprous iodide can form explosive alkynyl copper, thus limiting the further development of the reaction.

[0004] In view of this, the present invention proposes a new catalytic system and method for synthesizing diarylacetylene from calcium carbide and iodinated aromatics, which utilizes DBU salt to participate in the reaction of calcium carbide and iodinated aromatics to synthesize diarylacetylene. While ensuring the catalytic effect, the catalytic system can be simplified and the reaction safety can be improved. Summary of the invention

[0005] The purpose of the present invention is to provide a catalytic system for synthesizing diarylacetylene from calcium carbide and iodinated aromatics, using DBU salt stable under air as an organic base and an ionic ligand to realize a method for preparing diarylacetylene from calcium carbide and iodinated aromatics under mild conditions.

[0006] In order to achieve the above purpose, the technical solution adopted is:

[0007] A catalytic system for synthesizing diarylacetylene from calcium carbide and iodinated aromatic hydrocarbons, comprising: DBU ionic liquid, organic solvent, and palladium catalyst;

[0008] Wherein, the structural formula of the DBU ionic liquid is: In the formula, R=Me, Et, Pr, X=I, Br.

[0009] Further, the palladium catalyst is one of palladium acetate, palladium chloride, palladium nitrate, palladium acetylacetonate, palladium bromide, palladium / carbon, palladium trifluoroacetate, and bis(acetonitrile)palladium dichloride catalyst;

[0010] The organic solvent is one of dimethyl sulfoxide, methanol, ethanol, N,N-dimethylformamide, acetonitrile, benzene, chlorobenzene, toluene, 1,4-dioxane, dichloromethane, tetrahydrofuran, ethyl acetate, and petroleum ether;

[0011] The structural formula of the DBU ionic liquid is as follows:

[0012]

[0013] Furthermore, the structural formula of the DBU ionic liquid is:

[0014] Furthermore, the organic solvent is dimethyl sulfoxide or toluene.

[0015] Furthermore, the molar ratio of the DBU ionic liquid to the palladium catalyst is 1-5:100-500.

[0016] Another object of the present invention is to provide a catalytic system and method for synthesizing diarylacetylene from calcium carbide and iodinated aromatics. The above-mentioned catalytic system makes the reaction process mild and has good stability under air conditions.

[0017] A method for synthesizing diarylacetylene from calcium carbide and iodinated aromatic hydrocarbons adopts the above-mentioned catalytic system, calcium carbide and iodinated aromatic hydrocarbons as reactants, and synthesizes diarylacetylene through Sonogashira reaction.

[0018] Furthermore, the structural formula of the iodinated aromatic hydrocarbon is: Wherein: R=F, Cl, Br, CH3, OCH3, H, CN, CF3, Ph.

[0019] Further, the iodinated aromatic hydrocarbon is at least one of iodobenzene, 4-iodobenzeneacetonitrile, 4-ethyliodobenzene, 3-iodobenzonitrile, 3-chloroiodobenzene, 4-chloroiodobenzene, 4-iodotrifluorobenzoyl, p-iodotoluene, o-iodotoluene, m-iodotoluene, p-fluoroiodobenzene, o-fluoroiodobenzene, m-fluoroiodobenzene, 2-iodopyrazine, 2-iodopyridine, 2-iodothiophene, 2-iodomesitylene, and 1-iodonaphthalene.

[0020] Furthermore, the molar ratio of DBU ionic liquid, palladium catalyst, calcium carbide and iodinated aromatic hydrocarbon in the catalytic system is 1-5:1-5%:1-5:1;

[0021] The Sonogashira reaction is carried out in the presence of nitrogen or an inert gas at a temperature of 30-100° C. for a time of 1-72 hours.

[0022] Furthermore, the molar ratio of DBU ionic liquid, calcium carbide and iodinated aromatic hydrocarbon in the catalytic system is 3-5:2-4:1;

[0023] The Sonogashira reaction is carried out in the presence of nitrogen or an inert gas at a temperature of 40-70° C. for a time of 10-60 hours.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] my country has abundant coal resources. Coal coking is an important way to transform coal. Coke is one of the three main products of coal-coke transformation. Coke and calcium oxide can be used to prepare calcium carbide, so calcium carbide is an important coal derivative. As solid acetylene, calcium carbide has the advantages of being safe, cheap, easy to store, convenient to transport and easy to operate. The catalytic system and method for synthesizing diarylacetylene from calcium carbide and iodinated aromatics described in the present invention improve the reaction of synthesizing diarylacetylene from calcium carbide and has the following advantages:

[0026] 1. In the technical solution of the present invention, a simple pyridine compound ligand is used to prepare diarylacetylene from aryl iodide and calcium carbide under palladium catalysis, breaking the traditional method of preparing diarylacetylene from calcium carbide with the participation of organic phosphine ligands under inert conditions. In addition, the pyridine ligand (DBU) is cheap, commercially available, and has good stability under air.

[0027] 2. In the technical solution of the present invention, DBU salt is stable in air, and DBU is made into ionic liquid, which can better combine with calcium carbide and greatly improve the efficiency of the reaction. In addition, the Sonogashira coupling reaction involving calcium carbide is not limited to the system of co-catalyst, ligand and base, which provides an experimental basis for the industrial development of the reaction.

[0028] 3. In the technical scheme of the present invention, the DBU salt stable under air replaces the traditional system of co-catalyst, ligand and base, and under the catalysis of palladium, calcium carbide, a derivative of coal, is used as an alkyne source for cross-coupling with aryl iodide under mild conditions to prepare diarylacetylene in one pot. Iodinated aromatic hydrocarbons with different types of substituents can obtain symmetrical aryl acetylides in medium to high yields, and heterocyclic iodides can also be converted into corresponding diaryl alkynes in good yields.

[0029] 4. In the technical solution of the present invention, the catalytic system used in the reaction of synthesizing diarylacetylene has the advantages of mild conditions and simple steps, which provides an experimental basis for the commercial production of diarylacetylene by calcium carbide. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the H NMR spectrum of the product of Example 1;

[0031] Figure 2is the NMR carbon spectrum of the product of Example 1;

[0032] Figure 3 is the H NMR spectrum of the product of Example 2;

[0033] Figure 4 is the NMR carbon spectrum of the product of Example 2;

[0034] Figure 5 is the H NMR spectrum of the product of Example 3;

[0035] Figure 6 is the NMR carbon spectrum of the product of Example 3;

[0036] Figure 7 is the H NMR spectrum of the product of Example 4;

[0037] Figure 8 is the NMR carbon spectrum of the product of Example 4;

[0038] Fig. 9 is the H NMR spectrum of the product of Example 5;

[0039] Fig.10 is the NMR carbon spectrum of the product of Example 5;

[0040] Fig.11 This is the NMR fluorine spectrum of the product of Example 5;

[0041] Fig.12 is the H NMR spectrum of the product of Example 6;

[0042] Fig.13 is the NMR carbon spectrum of the product of Example 6;

[0043] Fig.14 This is the NMR fluorine spectrum of the product of Example 6;

[0044] Fig.15 is the H NMR spectrum of the product of Example 7;

[0045] Fig.16 is the NMR carbon spectrum of the product of Example 7;

[0046] Fig.17 is the H NMR spectrum of the product of Example 8;

[0047] Fig.18 is the NMR carbon spectrum of the product of Example 8;

[0048] Fig.19 is the H NMR spectrum of the product of Example 9;

[0049] Fig. 20 is the NMR carbon spectrum of the product of Example 9;

[0050] Fig.21 is the H NMR spectrum of the product of Example 10;

[0051] Fig. 22 is the NMR carbon spectrum of the product of Example 10;

[0052] Fig.23 This is the high-resolution spectrum of Example 17. DETAILED DESCRIPTION

[0053] In order to further explain the catalytic system and method for synthesizing diarylacetylene from calcium carbide and iodinated aromatics of the present invention and achieve the expected purpose of the invention, the catalytic system and method for synthesizing diarylacetylene from calcium carbide and iodinated aromatics proposed according to the present invention, its specific implementation method, structure, characteristics and efficacy are described in detail as follows in conjunction with preferred embodiments. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0054] The following will further introduce in detail the catalytic system and method for synthesizing diarylacetylene from calcium carbide and iodinated aromatic hydrocarbons of the present invention in conjunction with specific embodiments:

[0055] Calcium carbide is cheap, easy to obtain, safe, easy to transport, easy to store, easy to operate and abundant in resources. Therefore, in the prior art, calcium carbide, a byproduct of coal, is often used as an alkyne source and iodinated aromatics, and diarylacetylene is obtained through Sonogashira reaction under the catalysis of palladium / DBU salt. However, the existing synthesis reaction has the disadvantages of complex catalytic system, many safety issues, high cost, and harsh reaction conditions. Based on this, the technical scheme of the present invention is proposed, using DBU salt stabilized under air as an organic base, and realizing a method for preparing diarylacetylene under mild conditions of calcium carbide and iodinated aromatics under palladium catalysis, and using calcium carbide, a byproduct of coal, as an alkyne source and iodinated aromatics, and diarylacetylene is obtained through Sonogashira reaction under the catalysis of palladium / DBU salt. The technical scheme of the present invention is:

[0056] A catalytic system for synthesizing diarylacetylene from calcium carbide and iodinated aromatic hydrocarbons, comprising: DBU ionic liquid, organic solvent, and palladium catalyst;

[0057] Wherein, the structural formula of the DBU ionic liquid is: In the formula, R=Me, Et, Pr, X=I, Br.

[0058] Preferably, the palladium catalyst is one of palladium acetate, palladium chloride, palladium nitrate, palladium acetylacetonate, palladium bromide, palladium / carbon, palladium trifluoroacetate, and bis(acetonitrile)palladium dichloride catalyst.

[0059] Further preferably, the palladium catalyst is palladium acetate.

[0060] Further, the DBU ionic liquid is:

[0061] Further preferably, the DBU ionic liquid is:

[0062] In the above technical solution, the DBU ionic liquid acts as a strong base and also as a ligand, thereby streamlining the catalytic system. The DBU ionic liquid can be synthesized by using commercially available DBU well known in the art to form a salt.

[0063] Preferably, the organic solvent is one of dimethyl sulfoxide, methanol, ethanol, N,N-dimethylformamide, acetonitrile, benzene, chlorobenzene, toluene, 1,4-dioxane, dichloromethane, tetrahydrofuran, ethyl acetate and petroleum ether.

[0064] More preferably, the organic solvent is dimethyl sulfoxide or toluene.

[0065] Preferably, the molar ratio of the DBU ionic liquid to the palladium catalyst is 1-5:100-500.

[0066] A method for synthesizing diarylacetylene from calcium carbide and iodinated aromatic hydrocarbons adopts the above-mentioned catalytic system, calcium carbide and iodinated aromatic hydrocarbons as reactants, and synthesizes diarylacetylene through Sonogashira reaction.

[0067] Preferably, the structural formula of the iodinated aromatic hydrocarbon is: Wherein: R=F,Cl,Br,CH3,OCH3,H,CN,CF3,Ph.

[0068] In the above technical solution, the present invention mixes iodinated aromatic hydrocarbons, calcium carbide, palladium, and DBU salt, and then conducts a Sonogashira reaction. The reaction formula is as follows:

[0069]

[0070] In the reaction formula, the structural formula of calcium carbide is: The structural formula of diarylacetylene is The structural formula of iodinated aromatic hydrocarbons is: R=F, Cl, Br, CH3, OCH3, H, CN, CF3, Ph. The position of R is not limited, and the corresponding alkyne can be obtained in high yield when R is ortho, meta or para. Those skilled in the art can select specific iodinated aromatics according to actual needs.

[0071] Further preferably, the iodinated aromatic hydrocarbon is at least one of iodobenzene, 4-iodobenzeneacetonitrile, 3-chloroiodobenzene, 4-chloroiodobenzene, 4-iodotrifluorobenzoic acid, p-iodotoluene, o-iodotoluene, m-iodotoluene, p-fluoroiodobenzene, o-fluoroiodobenzene, m-fluoroiodobenzene, 2-iodopyrazine, 2-iodopyridine, 2-iodothiophene, 2-iodomesitylene, and 1-iodonaphthalene.

[0072] In the above technical solution, the iodinated aromatic hydrocarbons are all commercially available iodinated aromatic hydrocarbons and do not need to be further processed. The present invention has no special requirements on the conditions of the Sonogashira reaction, as long as the iodinated aromatic hydrocarbons meeting the above requirements can be obtained.

[0073] Preferably, the molar ratio of DBU ionic liquid, palladium catalyst, calcium carbide and iodinated aromatic hydrocarbon in the catalytic system is 1-5:1-5%:1-5:1;

[0074] The Sonogashira reaction is carried out in the presence of nitrogen or an inert gas at a temperature of 30-100° C. for a time of 1-72 hours.

[0075] Further preferably, the molar ratio of DBU ionic liquid, calcium carbide and iodinated aromatic hydrocarbon in the catalyst system is 3-5:2-4:1;

[0076] The Sonogashira reaction is carried out in the presence of nitrogen or an inert gas at a temperature of 40-70° C. for a time of 10-60 hours.

[0077] In the above technical solution, the molar percentage of DBU salt to iodinated aromatic hydrocarbon is preferably 300-500%, more preferably 400-500%; the molar percentage of calcium carbide to iodinated aromatic hydrocarbon is 1-5 times, more preferably 2-4 times. The present invention has no special requirements on the mixing method of the iodinated aromatic hydrocarbon, palladium source, DBU salt and calcium carbide, and any method known in the art that can be mixed evenly can be used.

[0078] The Sonogashira reaction is preferably carried out in the presence of nitrogen or an inert gas. The present invention has no special requirements on the type of the inert gas, and any inert gas known in the art can be used, specifically, but not limited to, argon.

[0079] The temperature of the olefin metathesis reaction, ie, the Sonogashira reaction, is preferably 30-100° C., more preferably 40-70° C., and the time is preferably 1-72 h, more preferably 10-60 h, and most preferably 20-30 h.

[0080] Preferably, the ratio of the organic solvent to the iodinated aromatic hydrocarbon is preferably (3-7) mL: (0.5-5.0) mmol, and more preferably 3 mL: (1.0-2.0) mmol.

[0081] The reaction equations of Examples 1-10 are as follows:

[0082]

[0083] Example 1.

[0084] The specific steps are as follows:

[0085] 1.0mmol iodobenzene, 3.0mmol calcium carbide, 5.0mmol DBU salt, 4mol% palladium acetate, 3.0mmol deionized water and 3mL dimethyl sulfoxide solvent were mixed, heated to 60°C under inert gas conditions, and then reacted for 24h. After the reaction was completed, 1,2-diphenylacetylene was separated by column chromatography, and the yield was 74%.

[0086] The product was characterized by NMR. Figure 1-2 shown. Figure 1 The corresponding 1,2-diphenylacetylene hydrogen spectrum data: 1 HNMR (400MHz, CDCl3): δ=7.59-7.50 (m, 4H), 7.35 (dd, J=4.9, 2.3Hz, 6H); Figure 2 The corresponding 1,2-diphenylacetylene carbon spectrum data: 13 C NMR (100MHz, CDCl3): δ=131.76, 128.49, 128.40, 123.42, 89.51ppm.

[0087] Example 2.

[0088] The specific steps are as follows:

[0089] 1.0mmol 4-methyliodobenzene (i.e., p-iodotoluene), 3.0mmol calcium carbide, 5.0mmol DBU salt, 4mol% palladium acetate, 3.0mmol deionized water and 3mL dimethyl sulfoxide solvent were mixed, heated to 60°C under inert gas conditions, and then reacted for 24h. After the reaction was completed, 1,2-di-p-tolueneacetylene was separated by column chromatography, and the yield was 70%.

[0090] The product was characterized by NMR. Figure 3-4 shown. Figure 3 The corresponding 1,2-di-p-tolueneacetylene hydrogen spectrum data: 1 HNMR (400MHz, CDCl3): δ = 7.45 (d, J = 8.1Hz, 4H), 7.17 (d, J = 8.0Hz, 4H), 2.39 (s, 6H); Figure 4 The corresponding carbon spectrum data of 1,2-di-p-tolueneacetylene: 13CNMR (100MHz, CDCl3) δ = 138.30, 131.57, 129.22, 120.52, 89.01ppm.

[0091] Example 3.

[0092] The specific steps are as follows:

[0093] 1.0mmol 4-ethyliodobenzene, 3.0mmol calcium carbide, 5.0mmol DBU salt, 4mol% palladium acetate, 3.0mmol deionized water and 3mL dimethyl sulfoxide solvent were mixed, heated to 60°C under inert gas conditions, and then reacted for 24h. After the reaction was completed, 1,2-di-p-ethylphenylacetylene was separated by column chromatography, and the yield was 72%.

[0094] The product was characterized by NMR. Figure 5-6 shown. Figure 5 The corresponding hydrogen spectrum data of 1,2-di-p-ethylphenylacetylene: 1 H NMR (400MHz, CDCl3): δ = 7.45 (d, J = 8.1Hz, 4H), 7.18 (d, J = 7.8Hz, 4H), 2.66 (q, J = 7.6Hz, 4H), 1.25 (t, J = 7.6Hz, 6H); Figure 6 The corresponding carbon spectrum data of 1,2-di-p-ethylphenylacetylene: 13 C NMR (100MHz, CDCl3): δ=144.6,131.7,128.0,120.8,89.0,29.0,15.5ppm.

[0095] Example 4.

[0096] The specific steps are as follows:

[0097] 1.0mmol 4-chloro-iodobenzene, 3.0mmol calcium carbide, 5.0mmol DBU salt, 4mol% palladium acetate, 3.0mmol deionized water and 3mL dimethyl sulfoxide solvent were mixed, heated to 60°C under inert gas conditions, and then reacted for 24h. After the reaction was completed, 1,2-bis(4-chlorophenyl)acetylene was obtained by column chromatography separation with a yield of 76%.

[0098] The product was characterized by NMR. Figure 7-8 shown. Figure 7 The corresponding 1,2-bis(4-chlorophenyl)acetylene hydrogen spectrum data: 1 H NMR (400MHz, CDCl3): δ=7.46(s,2H),7.44(s,2H),7.34(s,2H),7.32(s,2H); Figure 8The corresponding 1,2-bis(4-chlorophenyl)acetylene carbon spectrum data: 13 C NMR (100MHz, CDCl3): δ=134.67, 132.94, 128.90, 121.58, 89.32ppm.

[0099] Example 5.

[0100] The specific steps are as follows:

[0101] 1.0mmol 3-chloro-iodobenzene, 3.0mmol calcium carbide, 5.0mmol DBU salt, 4mol% palladium acetate, 3.0mmol deionized water and 3mL dimethyl sulfoxide solvent were mixed, heated to 60°C under inert gas conditions, and then reacted for 24h. After the reaction was completed, 1,2-bis(3-chlorophenyl)acetylene was obtained by column chromatography separation with a yield of 77%.

[0102] The product was characterized by NMR. Figure 9-10 shown. Fig. 9 The corresponding 1,2-bis(3-chlorophenyl)acetylene hydrogen spectrum data: 1 H NMR (400MHz, CDCl3): δ = 7.51 (s, 2H), 7.40 (d, J = 7.4Hz, 2H), 7.33 (d, J = 8.3Hz, 2H), 7.28 (t, J = 7.7Hz, 2H); 10 corresponding to the carbon spectrum data of 1,2-bis(3-chlorophenyl)acetylene: 13 C NMR (100MHz, CDCl3): δ=134.41,131.65,129.92,129.78,129.01,124.62,89.17ppm.

[0103] Example 6.

[0104] The specific steps are as follows:

[0105] 1.0mmol 4-fluoro-iodobenzene, 3.0mmol calcium carbide, 5.0mmol DBU salt, 4mol% palladium acetate, 3.0mmol deionized water and 3mL dimethyl sulfoxide solvent were mixed, heated to 60°C under inert gas conditions, and then reacted for 24h. After the reaction was completed, 1,2-bis(4-fluorophenyl)acetylene was obtained by column chromatography separation with a yield of 72%.

[0106] The product was characterized by NMR. Figure 11-13 shown. Fig.11 The corresponding 1,2-bis(4-fluorophenyl)acetylene hydrogen spectrum data: 1H NMR (400MHz, CDCl3): δ=7.50 (dd, J=8.8, 5.4Hz, 4H), 7.05 (t, J=8.7Hz, 4H); Fig.12 The corresponding 1,2-bis(4-fluorophenyl)acetylene carbon spectrum data: 13 C NMR (100MHz, CDCl3): δ=162.68(J C-F =248.2Hz),133.58(J C-F =8.4Hz),119.34(J C-F =3.4Hz),115.83(J C-F =21.9Hz),88.09; Fig.13 Corresponding 1,2-bis(4-fluorophenyl)acetylene fluorine spectrum data: 19 F NMR (376MHz, CDCl3): δ=-110.82ppm.

[0107] Example 7.

[0108] The specific steps are as follows:

[0109] 1.0mmol 2-fluoro-iodobenzene, 3.0mmol calcium carbide, 5.0mmol DBU salt, 4mol% palladium acetate, 3.0mmol deionized water and 3mL dimethyl sulfoxide solvent were mixed, heated to 60°C under inert gas conditions, and then reacted for 24h. After the reaction was completed, 1,2-bis(2-fluorophenyl)acetylene was obtained by column chromatography separation with a yield of 86%.

[0110] The product was characterized by NMR. Figure 14-16 shown. Fig.14 The corresponding 1,2-bis(2-fluorophenyl)acetylene hydrogen spectrum data: 1 H NMR (400MHz, CDCl3): δ = 7.56 (td, J = 7.4, 1.9Hz, 2H), 7.38-7.31 (m, 2H), 7.17-7.10 (m, 4H); Fig.15 The corresponding 1,2-bis(2-fluorophenyl)acetylene carbon spectrum data: 13 C NMR (100MHz, CDCl3): δ=162.77(d,J C-F =250.7Hz),133.662,130.49(d,J C-F =8Hz),124.2(d,J C-F =3.8Hz),115.7(d,J C-F =20.8Hz),111.7(d,J C-F =15.5Hz),87.8(d,JC-F =3.2Hz); Fig.16 The corresponding 1,2-bis(2-fluorophenyl)acetylene fluorine spectrum data: 19 F NMR (376MHz, CDCl3): δ=-109.51ppm.

[0111] Example 8.

[0112] The specific steps are as follows:

[0113] 1.0mmol 3-iodobenzene nitrile, 3.0mmol calcium carbide, 5.0mmol DBU salt, 4mol% palladium acetate, 3.0mmol deionized water and 3.0mL dimethyl sulfoxide solvent were mixed, heated to 60°C under inert gas conditions, and then reacted for 24h. After the reaction was completed, 3,3'-(acetylene-1,2-diyl) dibenzene nitrile was separated by column chromatography, and the yield was 71%.

[0114] The product was characterized by NMR. Figure 17-18 shown. Fig.17 The corresponding 3,3'-(ethyne-1,2-diyl)dibenzonitrile hydrogen spectrum data: 1 H NMR (400MHz, CDCl3): δ = 7.81 (s, 2H), 7.75 (d, J = 7.9Hz, 2H), 7.65 (d, J = 6.4Hz, 2H), 7.51 (d, J = 7.8Hz, 2H); Fig.18 The corresponding carbon spectrum data of 3,3'-(ethyne-1,2-diyl)dibenzonitrile: 13 CNMR (100MHz, CDCl3): δ=135.85,135.13,132.21,129.59,124.05,117.98,113.23,89.20ppm.

[0115] Example 9.

[0116] The specific steps are as follows:

[0117] 1.0mmol 1-iodonaphthalene, 3.0mmol calcium carbide, 5.0mmol DBU salt, 4mol% palladium acetate, 3.0mmol deionized water and 3mL dimethyl sulfoxide solvent were mixed, heated to 60°C under inert gas conditions, and then reacted for 24h. After the reaction was completed, 1,2-di(1-naphthyl)acetylene was separated by column chromatography, and the yield was 74%.

[0118] The product was characterized by NMR. Figure 19-20 shown. Fig.19 The corresponding 1,2-di(1-naphthyl)acetylene hydrogen spectrum data: 1H NMR (400MHz, CDCl3): δ = 8.59 (d, J = 8.3Hz, 2H), 7.95-7.88 (m, 6H), 7.68-7.63 (m, 2H), 7.55 (dt, J = 21.5, 8.1Hz, 4H); Fig. 20 The corresponding 1,2-di(1-naphthyl)acetylene carbon spectrum data: 13 C NMR (100MHz, CDCl3): δ=133.43,130.73,129.03,128.53,127.06,126.63,126.45,125.49,121.22,92.56ppm.

[0119] Example 10.

[0120] The specific steps are as follows:

[0121] 1.0mmol 2-iodothiophene, 3.0mmol calcium carbide, 5.0mmol DBU salt, 4mol% palladium acetate, 3.0mmol deionized water and 3mL dimethyl sulfoxide solvent were mixed, heated to 60°C under inert gas conditions, and then reacted for 24h. After the reaction was completed, 1,2-di(2-thienyl)acetylene was obtained by column chromatography separation with a yield of 83%.

[0122] The product was characterized by NMR. Figure 21-22 shown. Fig.21 The corresponding 1,2-di(2-thienyl)acetylene hydrogen spectrum data: 1 H NMR (400MHz, CDCl3): δ=7.35-7.24 (m, 4H), 7.02 (dd, J=5.1, 3.6Hz, 2H); Fig. 22 The corresponding 1,2-di(2-thienyl)acetylene carbon spectrum data: 13 C NMR (100MHz, CDCl3): δ=132.25, 127.76, 127.29, 123.06, 86.33ppm.

[0123] The hydrogen spectrum data and carbon spectrum data in Examples 1-10 confirm that the present invention indeed obtains diarylacetylene.

[0124] Example 11.

[0125] The operation steps of Example 11 are the same as those of Example 1, except for the selection of the palladium catalyst, as shown in Table 1.

[0126] Table 1

[0127]

[0128] Example 12.

[0129] The operation steps of Example 12 are the same as those of Example 1, except for the selection of organic solvents, as shown in Table 2.

[0130] Table 2

[0131]

[0132]

[0133] From Table 2, it can be seen that the organic solvent in the catalytic system has a certain influence on the reaction effect. The reason is that the DBU ionic liquid does not dissolve well in some organic solvents.

[0134] Example 13.

[0135] The operating steps of Example 13 are the same as those of Example 1, except for the selection of DBU salt (i.e., DBU ionic liquid), as shown in Table 3.

[0136] Table 3

[0137]

[0138] Example 14.

[0139] The operation steps of Example 14 are the same as those of Example 1, except for the selection of iodinated aromatic hydrocarbons, as shown in Table 4.

[0140] Table 4

[0141] Iodinated aromatic hydrocarbons product Yield 1 4-Iodophenylacetonitrile 4,4'-(Ethylene-1,2-diyl)dibenzonitrile 71％ 2 4-Iodotrifluorotoluene 1,2-Bis(4-(trifluoromethyl)phenyl)acetylene 74％ 3 o-Iodotol 1,2-Di-o-tolylacetylene 77％ 4 Meta-iodotoluene 1,2-Di-m-tolylacetylene 75％ 5 m-Fluoroiodobenzene 1,2-Bis(3-fluorophenyl)acetylene 73％ 6 2-Iodopyrazine 1,2-Bis(pyrazin-2-yl)acetylene 64％ 7 2-Iodomesitylene 1,1′-(1,2-ethynediyl)bis[2,4,6]-trimethyl 55％ 8 1-Iodonaphthalene 1,2-Di(naphthyl)acetylene 70％

[0142] Example 15.

[0143] The operating steps of Example 15 are the same as those of Example 1, except for the selection of the amount of calcium carbide, the amount of DBU salt, the amount of palladium catalyst and the reaction conditions, as shown in Table 5.

[0144] Table 5

[0145]

[0146]

[0147] Example 16.

[0148] The specific steps are as follows:

[0149] 1.0mmol iodobenzene, 3.0mmol calcium carbide, 5.0mmol DBU, 4mol% palladium acetate, 3.0mmol deionized water and 3mL dimethyl sulfoxide solvent were mixed, heated to 60°C under nitrogen, and then reacted for 24h. After the reaction was completed, column chromatography was used to separate and obtain 1,2-diphenylacetylene with a yield of 42%. The product NMR was consistent with Example 2.

[0150] In this example, as a comparison, palladium / DBU was used to prepare diarylacetylene with iodobenzene and calcium carbide, and a yield of 42% was obtained. Compared with the yield of 74% in Example 1, it was found that DBU salt can better contact with the reactants, thereby greatly improving the yield.

[0151] Example 17.

[0152] The specific steps are as follows:

[0153] 3.0 mmol of calcium carbide, 5.0 mmol of DBU salt, 3.0 mmol of deionized water and 3 mL of dimethyl sulfoxide solvent were mixed, heated to 60°C, and reacted for 24 hours. After the reaction was completed, high-resolution capture was performed.

[0154] In order to explore the mechanism, this example attempts to capture the intermediate of DBU salt combined with calcium carbide. The intermediate formed by calcium carbide and DBU salt is captured by high resolution. The high resolution spectrum of the intermediate is as follows: Fig.23 As shown. It can be seen that it has the advantages of:

[0155] (1) It was confirmed that DBU salt can combine with insoluble calcium carbide to form an intermediate that is soluble in the system, thereby greatly improving the yield of the reaction.

[0156] (2) In the existing reaction of calcium carbide with iodinated aromatics, calcium carbide reacts with water to generate acetylene, which is easy to escape, and the reaction between calcium carbide and water is violent, which has certain safety issues. However, the intermediate formed by calcium carbide and DBU salt in the present invention is dissolved in the reaction system throughout the reaction process, and there is no problem of escape; and the reaction is mild, and there is no safety problem.

[0157] It can be seen from the above embodiments that the present invention provides a method for preparing diarylacetylene under mild conditions by using DBU salt as an organic base and calcium carbide and iodinated aromatic hydrocarbons under palladium catalysis. Calcium carbide, a by-product derived from coal, is used as a raw material and iodinated aromatic hydrocarbons, and a Sonogashira coupling reaction occurs after in-situ catalysis of palladium. The corresponding diarylacetylene is obtained by selecting different iodinated aromatic hydrocarbons, and the yield of diarylacetylene ranges from 70 to 86%.

[0158] The above is only a preferred embodiment of the embodiment of the present invention, and does not impose any form of limitation on the embodiment of the present invention. Any simple modification, equivalent changes and modifications made to the above embodiment based on the technical essence of the embodiment of the present invention are still within the scope of the technical solution of the embodiment of the present invention.

Claims

1. A catalytic system for synthesizing diarylacetylene from calcium carbide and iodinated aromatics, characterized in that: include: DBU ionic liquid, organic solvent, palladium catalyst; Wherein, the structural formula of the DBU ionic liquid is: In the formula, R=Me, Et, Pr, X=I, Br.

2. The catalytic system according to claim 1, characterized in that The palladium catalyst is one of palladium acetate, palladium chloride, palladium nitrate, palladium acetylacetonate, palladium bromide, palladium / carbon, palladium trifluoroacetate, and bis(acetonitrile)palladium dichloride catalyst; The organic solvent is one of dimethyl sulfoxide, methanol, ethanol, N,N-dimethylformamide, acetonitrile, benzene, chlorobenzene, toluene, 1,4-dioxane, dichloromethane, tetrahydrofuran, ethyl acetate, and petroleum ether; The structural formula of the DBU ionic liquid is as follows:

3. The catalytic system according to claim 2, characterized in that The structural formula of the DBU ionic liquid is:

4. The catalytic system according to claim 2, characterized in that The palladium catalyst is palladium acetate; The organic solvent is dimethyl sulfoxide or toluene.

5. The catalytic system according to claim 1, characterized in that The molar ratio of the DBU ionic liquid to the palladium catalyst is 1-5:100-500.

6. A method for synthesizing diarylacetylene from calcium carbide and iodinated aromatic hydrocarbons, characterized in that: The catalytic system according to any one of claims 1 to 5 is used to synthesize diarylacetylene through the Sonogashira reaction with calcium carbide and iodinated aromatic hydrocarbons as reactants.

7. The method according to claim 6, characterized in that The structural formula of the iodinated aromatic hydrocarbon is: Wherein: R=F, Cl, Br, CH3, OCH3, H, CN, CF3, Ph.

8. The method according to claim 7, characterized in that The iodinated aromatic hydrocarbon is at least one of iodobenzene, 4-iodobenzeneacetonitrile, 4-ethyliodobenzene, 3-iodobenzonitrile, 3-chloroiodobenzene, 4-chloroiodobenzene, 4-iodotrifluorobenzoyl, p-iodotoluene, o-iodotoluene, m-iodotoluene, p-fluoroiodobenzene, o-fluoroiodobenzene, m-fluoroiodobenzene, 2-iodopyrazine, 2-iodopyridine, 2-iodothiophene, 2-iodomesitylene, and 1-iodonaphthalene.

9. The method according to claim 6, characterized in that The molar ratio of DBU ionic liquid, palladium catalyst, calcium carbide and iodinated aromatic hydrocarbon in the catalytic system is 1-5:1-5%:1-5:1; The Sonogashira reaction is carried out in the presence of nitrogen or an inert gas at a temperature of 30-100° C. for a time of 1-72 hours.

10. The method according to claim 9, characterized in that The molar ratio of DBU ionic liquid, calcium carbide and iodinated aromatic hydrocarbon in the catalytic system is 3-5:2-4:1; The Sonogashira reaction is carried out in the presence of nitrogen or an inert gas at a temperature of 40-70° C. for a time of 10-60 hours.

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