Synthesis method of 5H-dibenzo [a, d] cycloheptene skeleton

Abstract

The invention relates to the technical field of synthesis of a 5H-dibenzo [a, d] cycloheptene skeleton, in particular to a synthesis method of the 5H-dibenzo [a, d] cycloheptene skeleton. Comprising the following steps: sequentially adding a catalyst, a ligand, alkali, a reactant I, a reactant II, a p-xylene solution and a magneton 5 into a reactor, connecting a condensing pipe, introducing condensed water from bottom to top, putting the reactor into an oil bath pan at 60-100 DEG C, heating, stirring and reacting for 6-24 hours, terminating the reaction, and purifying the product to obtain a 5H-dibenzo [a, d] cycloheptene skeleton product; the reactant I comprises 2-(2-bromophenyl)-1-acetophenone, 2-(2-bromophenyl)-1-(4-methylphenyl) ethanone, 2-(2-bromo-5-methylphenyl)-1-acetophenone or 2-(2-bromo-4-methoxyphenyl)-1-acetophenone, and the reactant II comprises 2-(2-bromophenyl)-1-(4-methylphenyl) ethanone, 2-(2-bromo-5-methylphenyl)-1-acetophenone or 2-(2-bromo-4-methoxyphenyl)-1-acetophenone; the reactant II comprises bicyclo [2.2. 1] heptyl-2, 5-diene-2, 3-dimethyl dicarboxylate, and the reactant II comprises bicyclo [2.2. 1] heptyl-2, 5-diene-2, 3-dimethyl dicarboxylate; the method is mild in reaction condition, high in selectivity, relatively high in yield and environment-friendly; the active product can be used in the field of synthesis of drugs, pesticides and paint dyes.

Description

Technical Field

[0001] This invention relates to the field of 5H-dibenzo[a,d]cycloheptene skeleton synthesis technology, specifically to a method for synthesizing 5H-dibenzo[a,d]cycloheptene skeleton. Background Technology

[0002] The 5H-dibenzo[a,d]cycloheptene skeleton is an important chemical intermediate and product, with wide applications in pharmaceuticals, pesticides, coatings, analytical reagents, and dye manufacturing. For example, cyclobenzaline, an important drug used to relieve muscle spasms associated with acute, painful musculoskeletal disorders, and diphenylcycloheptidine, an important anti-allergic drug, are examples. The applications of these 5H-dibenzo[a,d]cycloheptene skeleton compounds make the research on their synthesis more practically valuable.

[0003] There are many methods for synthesizing the 5H-dibenzo[a,d]cycloheptene skeleton. For example, intramolecular hydrogenation and electronucleophilic cyanation reactions of 1-benzyl-2-ethynylbenzene derivatives were achieved using Au(I) catalyst and AgSbF6, respectively, to construct dibenzocycloheptadiene. However, these reaction conditions have certain limitations, such as expensive and unsuitable catalysts, hazardous preparation conditions, and environmental pollution. Another example is the Lewis acid-promoted intramolecular hydrogenation reaction of ethynylbenzene with ortho-aryl alkyl groups to obtain alkylene dibenzo[a,d]cycloheptene. These reactions require the addition of Lewis acid reagents. Although they can effectively synthesize the desired 5H-dibenzo[a,d]cycloheptene skeleton, the wastewater or exhaust gas generated during the post-experimental treatment causes severe environmental pollution. For example, in a new synthetic method for the 5H-dibenzo[a,d]cycloheptene skeleton, the initiator trifluoromethanesulfonic anhydride is required. This reagent is highly reactive and extremely sensitive to moisture, and its storage, transportation and use require special conditions (such as a glove box).

[0004] Therefore, there is an urgent need to develop a simple, mild, and environmentally friendly method for synthesizing the 5H-dibenzo[a,d]cycloheptene skeleton. Summary of the Invention

[0005] In view of this, the present invention proposes a method for synthesizing the 5H-dibenzo[a,d]cycloheptene skeleton, specifically a method for the synthesis of a seven-membered cyclization reaction of a brominated aromatic hydrocarbon derivative that is simple in process, mild in reaction, and environmentally friendly. This method uses stable and readily available raw materials, achieves efficient construction of the target skeleton in a single step under mild reaction conditions, and exhibits excellent substrate versatility. The technical solution of the present invention is implemented as follows: In a first aspect, the present invention proposes a method for synthesizing a 5H-dibenzo[a,d]cycloheptene skeleton, characterized by comprising the following steps: sequentially adding a catalyst, a ligand, a base, reactant one, reactant two and p-xylene solution to a reactor, heating and stirring the reaction under condensation conditions, terminating the reaction and purifying the product to obtain a 5H-dibenzo[a,d]cycloheptene skeleton product; The first reactant is selected from one of 2-(2-bromophenyl)-1-acetophenone, 2-(2-bromophenyl)-1-(4-methylphenyl)acetophenone, 2-(2-bromo-5-methylphenyl)-1-acetophenone, and 2-(2-bromo-4-methoxyphenyl)-1-acetophenone; the second reactant is selected from dimethyl bicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid.

[0006] Specifically, the present invention relates to a seven-membered cyclization reaction of brominated aromatic hydrocarbon derivatives, wherein 2-(2-bromophenyl)-1-phenylethyl ketone or its derivatives provide 5 carbon atoms, and the bicyclic [2.2.1]hept-2,5-diene-2,3-dicarboxylic acid dimethyl ester provides 2 carbon atoms, and a seven-membered ring is prepared by a one-step method.

[0007] Specifically, the p-xylene solution is used as a reaction solvent to dissolve reactant one, reactant two, catalyst, ligand, and base.

[0008] Preferably, the ratio of reactant one, reactant two, and p-xylene solution is 0.2 mmol: (0.2-0.3 mmol): 2 mL.

[0009] Preferably, the catalyst is selected from palladium acetate (Pd(OAc)2), palladium chloride (PdCl2), palladium trifluoroacetate (Pd(TFA)2), tetra-triphenylphosphine palladium (Pd(PPh3)4), bis(triphenylphosphine) dichloride palladium (Pd(PPh3)2Cl2), and tris(dibenzylideneacetone) dipalladium (Pd2(dba)3).

[0010] Preferably, the ligand is selected from one of 2-dicyclohexylphosphino-2'-(N,N-dimethylamine)-biphenyl (DavePhos), 2-diphenylphosphino-2'-(N,N-dimethylamino)biphenyl (PhDavePhos), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (X-phos), 1,1'-bis(diphenylphosphine)ferrocene (dppf), 4,5-bisdiphenylphosphino-9,9-dimethyloxanthracene (Xantphos), and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine (BINAP).

[0011] Specifically, Pd(II) in the catalyst is reduced to Pd(0)palladium by the ligand, which initiates the catalytic cycle. Its base is deprotonated in the ortho-CH activation. The purpose of changing the palladium-based material with various ligands is to optimize the activity, selectivity and reaction compatibility of the catalyst by adjusting its coordination properties.

[0012] Preferably, the alkali is selected from one of potassium bicarbonate (KHCO3), cesium carbonate (Cs2CO3), sodium carbonate (Na2CO3), lithium carbonate (Li2CO3), potassium hydroxide (KOH), and potassium acetate (KOAc).

[0013] Preferably, the molar ratio of reactant 1, catalyst and ligand is 1:(0.1-0.2):(0.1-0.2).

[0014] More preferably, the molar ratio of reactant 1, catalyst and ligand is 1:0.1:0.1, at which point the reaction activity is good and the yield of 5H-dibenzo[a,d]cycloheptene skeleton reaches 91%.

[0015] Preferably, the molar ratio of reactant one to base is 1:(1.5-2).

[0016] More preferably, the molar ratio of reactant one to base is 1:1.5, at which point the reactivity is good and the yield of the 5H-dibenzo[a,d]cycloheptene skeleton reaches 91%.

[0017] Preferably, the reaction temperature of the synthesis method is 60~100℃ and the reaction time is 6~24h.

[0018] Preferably, the purity of reactant one is not less than 98%, the purity of reactant two is not less than 97%, the purity of catalyst is not less than 98%, the purity of ligand is not less than 98%, the purity of base is not less than 98%, and the purity of p-xylene is not less than 99.5%.

[0019] Preferably, the bottom of the reactor is immersed in silicone oil, and the immersion depth is such that the height of the silicone oil is higher than the height of the reaction liquid inside the reactor.

[0020] Preferably, the stirring speed of the reaction is 100~700 rpm.

[0021] Preferably, the method of terminating the reaction includes stopping heating.

[0022] Preferably, the purification method specifically includes: extraction with ethyl acetate, combining the resulting organic phases, drying by rotary evaporation, and separating and purifying the crude product by column chromatography to obtain the 5H-dibenzo[a,d]cycloheptene skeleton.

[0023] In a second aspect, the present invention provides a 5H-dibenzo[a,d]cycloheptene skeleton compound prepared by the synthetic method described in the first aspect.

[0024] Compared with the prior art, the advantages of the present invention are as follows: (1) This invention proposes a novel method for catalyzing C(sp) through a catalyst (Pd(OAc)2) / ligand (DavePhos). 3 The 5H-dibenzo[a,d]cycloheptene skeleton is synthesized by the )-H activation reaction. The reaction raw materials of this invention have the advantages of being inexpensive, readily available, and environmentally friendly.

[0025] (2) The present invention constructs the 5H-dibenzo[a,d]cycloheptene skeleton in a "one-step" manner. The reaction steps are few and the reaction is carried out at atmospheric pressure. The reaction is not only mild and simple to operate, but also significantly reduces the preparation cost of the 5H-dibenzo[a,d]cycloheptene skeleton and reduces pollution. Therefore, it is easier to industrialize and promote.

[0026] (3) The dibenzocycloheptacyclic compounds synthesized in this invention can be applied to fields such as drug synthesis, pesticide synthesis and paint and dye synthesis. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The reaction equation for the synthesis of the 5H-dibenzo[a,d]cycloheptene skeleton in Example 1 of this invention is shown. Detailed Implementation

[0029] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0031] In this document, the terms “containing,” “comprising,” or “including” are open-ended expressions, meaning they include the contents specified in this invention but do not exclude other aspects.

[0032] In this document, the terms “optional,” “optionally,” or “optional” generally refer to an event or condition that may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0034] All materials used in this invention were purchased from the market, specifically: 2-(2-bromophenyl)-1-acetophenone, 2-(2-bromophenyl)-1-(4-methylphenyl)acetophenone, 2-(2-bromo-5-methylphenyl)-1-acetophenone, 2-(2-bromo-4-methoxyphenyl)-1-acetophenone, and dimethyl bicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid were purchased from Shanghai Bide Pharmaceutical Technology Co., Ltd.; Pd(OAc)2 was purchased from Anhui Zesheng Technology Co., Ltd.; Davephos was purchased from Shanghai Bide Pharmaceutical Technology Co., Ltd.; KHCO3 was purchased from Sinopharm Group; and p-xylene was purchased from Sinopharm Group.

[0035] Example 1

[0036] This embodiment provides a method for synthesizing the 5H-dibenzo[a,d]cycloheptene skeleton, such as... Figure 1 As shown, the product is specifically 2-(5-benzoyl-5H-dibenzo[a,d][7]annulen-1-yl)-1-phenylethyl ketone, and its structural formula is as follows: The synthesis method specifically includes the following steps: Add 0.02 mmol of Pd(OAc)₂, 0.02 mmol of Davephos, 0.3 mmol of KHCO₃, 0.2 mmol of 2-(2-bromophenyl)-1-acetophenone, 0.2 mmol of dimethyl bicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylate, 2 mL of p-xylene solution, and a No. 5 magnetic stir bar in that order. After circulating cooling water through the condenser tube from bottom to top, place the reactor in a 100°C oil bath and heat for 8 h. The bottom spherical container of the reactor is immersed in silicone oil, with the immersion depth being such that the height of the silicone oil is higher than the height of the reaction liquid in the spherical container of the micro-reaction tube. The magnetic stirrer speed is adjusted to 700 rpm. After the reaction is completed, pour the reaction solution into a separatory funnel, add 15 mL of distilled water, and then extract three times with 10 mL of ethyl acetate. The obtained organic phases were combined and dried by rotary evaporation. The crude product was separated and purified by column chromatography to obtain 38.09 mg of 2-(5-benzoyl-5H-dibenzo[a,d][7]annulen-1-yl)-1-phenylethyl ketone as a white solid with a yield of 91%.

[0037] The NMR data for this product are: hydrogen NMR. 1 H NMR (400 MHz, DMSO) δ 8.10 – 7.96(m, 2H), 7.76 – 7.57 (m, 5H), 7.51 (dd, J = 8.3, 7.1 Hz, 2H), 7.45 – 7.33 (m,3H), 7.33 – 7.17 (m, 4H), 7.12 (dd, J = 7.6, 1.3 Hz, 1H), 6.90 (d, J = 12.1 Hz, 1H), 6.81 (d, J = 12.1 Hz, 1H), 6.11 (s, 1H), 4.72 (d, J = 17.5 Hz, 1H), 4.37 (d, J = 17.5 Hz, 1H); 13C NMR (101 MHz, DMSO) δ 197.67, 197.08, 138.72, 137.87, 137.78, 136.32, 134.40, 133.66, 133.31, 133.14, 131.49, 130.64, 129.71, 129.47, 128.69, 128.60, 128.49, 128.29, 128.27, 128.09, 127.89, 127.80, 127.70, 126.44, 60.98, 43.09; demonstrating the successful preparation of Example 1.

[0038] Example 2

[0039] This embodiment provides a method for synthesizing the 5H-dibenzo[a,d]cycloheptene skeleton, specifically the product being 2-(5-(4-methylbenzoyl)-5H-dibenzo[a,d][7]annulen-1-yl)-1-(p-tolyl)acetone, with the following structural formula: The synthesis method specifically includes the following steps: Add 0.02 mmol of Pd(OAc)2, 0.02 mmol of Davephos, 0.3 mmol of KHCO3, 0.2 mmol of 2-(2-bromophenyl)-1-(4-methylphenyl)ethyl ketone, 0.2 mmol of dimethyl bicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid, 2 mL of p-xylene solution, and a No. 5 magnetic stir bar in that order. After circulating cooling water through the condenser tube from bottom to top, place the reactor in a 100°C oil bath and heat for 8 h. The bottom spherical container of the reactor is immersed in silicone oil, with the immersion depth being such that the height of the silicone oil is higher than the height of the reaction liquid in the spherical container of the micro-reaction tube. The magnetic stirrer speed is adjusted to 700 rpm. After the reaction is completed, pour the reaction solution into a separatory funnel, add 15 mL of distilled water, and then extract three times with 10 mL of ethyl acetate. The obtained organic phases were combined and dried by rotary evaporation. The crude product was purified by column chromatography to obtain 39.78 mg of 2-(5-(4-methylbenzoyl)-5H-dibenzo[a,d][7]arunen-1-yl)-1-(p-tolyl)acetone, a white solid with a yield of 90%.

[0040] The NMR data for this product are: hydrogen NMR. 1 H NMR (400 MHz, DMSO) δ 7.91 (d, J =8.0 Hz, 2H), 7.67 (d, J = 7.6 Hz, 1H), 7.59 (dd, J= 7.8, 1.3 Hz, 1H), 7.53 (d, J =8.0 Hz, 2H), 7.42 – 7.28 (m, 4H), 7.28 – 7.18 (m, 2H), 7.14 – 7.05 (m, 3H), 6.87 (d, J = 12.1 Hz, 1H), 6.79 (d, J = 12.1 Hz, 1H), 6.07 (s, 1H), 4.66 (d, J =17.3 Hz, 1H), 4.32 (d, J = 17.3 Hz, 1H), 2.37 (s, 3H), 2.23 (s, 3H).; 13 C NMR (101 MHz, DMSO) δ 197.41, 197.23, 144.10, 142.28, 139.41, 138.46, 135.67, 135.02, 134.43, 134.38, 133.86, 131.18, 130.21, 130.03, 129.80, 129.73, 129.23, 129.05, 128.97, 128.86, 128.82, 128.57, 128.43, 126.97, 61.48, 43.53, 21.64, 21.44; demonstrating the successful preparation in Example 2.

[0041] Example 3

[0042] This embodiment provides a method for synthesizing the 5H-dibenzo[a,d]cycloheptene skeleton, specifically the product 2-(5-benzoyl-3,7-dimethyl-5H-dibenzo[a,d][7]annulen-1-yl)-1-phenylethyl ketone, the structural formula of which is: The synthesis method specifically includes the following steps: Add 0.02 mmol of Pd(OAc)₂, 0.02 mmol of Davephos, 0.3 mmol of KHCO₃, 0.2 mmol of 2-(2-bromo-5-methylphenyl)-1-acetophenone, 0.2 mmol of dimethyl bicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylate, 2 mL of p-xylene solution, and a No. 5 magnetic stir bar in that order. After circulating cooling water through the condenser tube from bottom to top, place the reactor in a 100°C oil bath and heat for 8 h. The bottom spherical container of the reactor is immersed in silicone oil, with the immersion depth being such that the height of the silicone oil is higher than the height of the reaction liquid in the spherical container of the micro-reaction tube. The magnetic stirrer speed is adjusted to 700 rpm. After the reaction is completed, pour the reaction solution into a separatory funnel, add 15 mL of distilled water, and then extract three times with 10 mL of ethyl acetate. The obtained organic phases were combined and dried by rotary evaporation. The crude product was separated and purified by column chromatography to obtain 29.17 mg of 2-(5-benzoyl-3,7-dimethyl-5H-dibenzo[a,d][7]arunen-1-yl)-1-phenylethyl ketone, which was a white solid with a yield of 66%.

[0043] The NMR data for this product are: hydrogen NMR. 1 H NMR (400 MHz, DMSO) δ 8.05 – 7.96(m, 2H), 7.61 (t, J = 7.3 Hz, 3H), 7.50 (dd, J = 14.0, 6.3 Hz, 3H), 7.41 – 7.38(m, 1H), 7.35 (d, J = 7.3 Hz, 1H), 7.28 (t, J = 7.5 Hz, 2H), 7.11 (d, J = 7.8 Hz, 1H), 7.01 (dd, J = 7.9, 1.8 Hz, 1H), 6.92 (d, J = 1.8 Hz, 1H), 6.79 (d, J = 12.0Hz, 1H), 6.71 (d, J = 12.0 Hz, 1H), 5.95 (s, 1H), 4.65 (d, J = 17.4 Hz, 1H), 4.29(d, J = 17.4 Hz, 1H), 2.32 (s, 3H), 2.30 (s, 3H); 13 C NMR (101 MHz, DMSO) δ197.56 (d,J = 61.6 Hz), 138.67, 138.01 (d, J = 17.0 Hz), 137.60 (d, J = 15.4 Hz), 136.47, 133.40 (d, J = 31.9 Hz), 131.82 (d, J = 52.0 Hz), 130.70 (d, J = 49.8 Hz),129.97, 129.37, 128.73, 128.26 (d, J = 12.0 Hz), 127.86 (d, J = 11.4 Hz), 127.18(d, J = 2.9 Hz), 59.79, 43.11, 20.73 (d, J = 16.4 Hz); this demonstrates the successful preparation of Example 3.

[0044] Example 4

[0045] This embodiment provides a method for synthesizing the 5H-dibenzo[a,d]cycloheptene skeleton, specifically the product being 2-(5-benzoyl-4,8-dimethoxy-5H-dibenzo[a,d][7]annulen-1-yl)-1-phenylethyl ketone, the structural formula of which is: The synthesis method specifically includes the following steps: Add 0.02 mmol of Pd(OAc)₂, 0.02 mmol of Davephos, 0.3 mmol of KHCO₃, 0.2 mmol of 2-(2-bromo-4-methoxyphenyl)-1-acetophenone, 0.2 mmol of dimethyl bicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylate, 2 mL of p-xylene solution, and a No. 5 magnetic stir bar in that order. After circulating cooling water through the condenser tube from bottom to top, place the reactor in a 100°C oil bath and heat for 8 h. The bottom spherical container of the reactor is immersed in silicone oil, with the immersion depth being such that the height of the silicone oil is higher than the height of the reaction liquid in the spherical container of the micro-reaction tube. The magnetic stirrer speed is adjusted to 700 rpm. After the reaction is completed, pour the reaction solution into a separatory funnel, add 15 mL of distilled water, and then extract three times with 10 mL of ethyl acetate. The obtained organic phases were combined and dried by rotary evaporation. The crude product was separated and purified by column chromatography to obtain 37.45 mg of 2-(5-benzoyl-4,8-dimethoxy-5H-dibenzo[a,d][7]annulen-1-yl)-1-phenylethyl ketone as a white solid with a yield of 79%.

[0046] The NMR data for this product are: hydrogen NMR. 1 H NMR (400 MHz, DMSO) δ 8.04 – 7.93(m, 2H), 7.63 (t, J = 7.4 Hz, 1H), 7.58 – 7.47 (m, 4H), 7.43 (d, J = 8.4 Hz, 1H), 7.38 (t, J = 7.4 Hz, 1H), 7.28 (t, J = 7.6 Hz, 2H), 7.04 (s, 2H), 6.95 (dd, J =8.4, 2.7 Hz, 1H), 6.82 (d, J = 23.1 Hz, 3H), 6.31 (s, 1H), 4.60 (d, J = 17.5 Hz, 1H), 4.23 (d, J = 17.5 Hz, 1H), 3.98 (s, 3H), 3.71 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 198.50, 197.49, 157.82, 154.06, 138.05, 136.46, 136.08, 134.12, 133.20, 131.75, 131.69, 130.74, 130.68, 130.15, 128.71, 128.20, 128.02, 127.72, 127.27, 127.08, 125.70, 114.77, 112.78, 110.79, 56.32, 55.15, 50.80, 42.62; demonstrating the successful preparation of Example 4.

[0047] The synthesis methods and yields of other embodiments and comparative examples are shown in Table 1. Reactant 1 and Reactant 2 and their amounts are the same as in Example 1. The remaining raw materials and their amounts, reaction temperature and reaction time are shown in Table 1.

[0048] Table 1. Yields of 5H-dibenzo[a,d]cycloheptene skeleton synthesized under different conditions

[0049] The synthesis methods and yields of other examples and comparative examples are shown in Table 2. The reactants, solvents, catalysts, ligands and bases and their amounts, reaction temperatures and reaction times are the same as in Example 1. The reactants and their amounts are shown in Table 2.

[0050] Table 2. Yields of 5H-dibenzo[a,d]cycloheptene skeleton synthesized under different conditions

[0051] In summary, this synthesis reaction yields good results at temperatures ranging from 60 to 100°C and reaction times from 6 to 24 hours, with 8 hours and 100°C being the optimal conditions. Too low a temperature results in insufficient reaction kinetics to overcome the high energy barriers of CH activation and oxidative addition steps; too low a time leaves insufficient time for reactants and intermediates to complete the entire multi-step cascade cycle; too high a time increases costs; and too high a temperature requires large equipment and promotes side reactions.

[0052] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for the synthesis of 5H-dibenzo[a,d]cycloheptene skeleton, characterized by, The method comprises the following steps: sequentially adding a catalyst, a ligand, a base, a reactant one, a reactant two and a p-xylene solution into a reactor, stirring and heating the reaction under condensation, purifying the product after the reaction is terminated, and obtaining a 5H-dibenzo[a,d]cycloheptene skeleton product. The reactant one is selected from one of 2-(2-bromophenyl)-1-phenylethanone, 2-(2-bromophenyl)-1-(4-methylphenyl)ethanone, 2-(2-bromo-5-methylphenyl)-1-phenylethanone and 2-(2-bromo-4-methoxyphenyl)-1-phenylethanone; and the reactant two is selected from dimethyl bicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylate.

2. The method of synthesis of claim 1, wherein, The ratio of the use amount of the reactant one, the reactant two and the p-xylene solution is 0.2 mmol:(0.2-0.3 mmol):2 mL.

3. The method of synthesis of claim 1, wherein, The catalyst is selected from one of palladium acetate, palladium chloride, palladium trifluoroacetate, palladium tetraphenylphosphine, dichlorobistriphenylphosphine palladium and tris(dibenzylideneacetone)dipalladium.

4. The method of synthesis of claim 3, wherein, The ligand is selected from one of 2-dicyclohexylphosphino-2'-(N,N-dimethylamino)-biphenyl, 2-diphenylphosphino-2'-(N,N-dimethylamino)biphenyl, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, 1,1'-bis(diphenylphosphino)ferrocene, 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene and 1,1'-binaphthalene-2,2'-bis(diphenylphosphine).

5. The method of synthesis of claim 4, wherein, The molar ratio of the reactant one, the catalyst and the ligand is 1:(0.1-0.2):(0.1-0.2).

6. The method of synthesis of claim 1, wherein, The base is selected from one of potassium bicarbonate, cesium carbonate, sodium carbonate, lithium carbonate, potassium hydroxide and potassium acetate.

7. The method of synthesis of claim 6, wherein, The molar ratio of the reactant one and the base is 1:(1.5-2).

8. The method of synthesis of claim 1, wherein, The reaction temperature of the synthesis method is 60-100 DEG C, and the reaction time is 6-24 h.

9. The method of synthesis of claim 1, wherein, The purity of the reactant one is not less than 98%, the purity of the reactant two is not less than 97%, the purity of the catalyst is not less than 98%, the purity of the ligand is not less than 98%, the purity of the base is not less than 98%, and the purity of the p-xylene is not less than 99.5%. 10.A 5H-dibenzo[a,d]cycloheptene skeleton compound prepared by the synthesis method in any one of claims 1-9.

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