A method for synthesizing a hydrazobenzene and the hydrazobenzene
By synthesizing hydrazine by reacting pinacolborane with azobenzene compounds under anhydrous cobalt chloride catalysis, the environmental pollution and expensive catalyst problems of existing methods are solved, and the synthesis of hydrazine with high yield and structural diversity is achieved.
Patent Information
- Application Number
- CN202410091955.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-23
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2044-01-23
AI Technical Summary
Existing methods for synthesizing hydrazine azobenzene suffer from environmental pollution, expensive catalysts, difficulty in controlling the reaction, excessive reduction, poor tolerance of functional groups, and toxicity of hydrogen transfer reagents.
Anhydrous cobalt chloride was used as a catalyst and pinacolborane as a boron source to react with azobenzene compounds under an anaerobic environment to synthesize hydrogenated azobenzene compounds via hydroboration, followed by chromatographic purification.
The synthesis of structurally diverse hydrazobenzene compounds has been achieved. The method is simple, widely applicable, and has significantly improved environmental friendliness and substrate versatility. It also has high yield and avoids the shortcomings of traditional methods.
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Figure CN118026884B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of organic synthesis, and particularly relates to a synthesis method of hydrazobenzene and hydrazobenzene. BACKGROUND
[0002] Azobenzene and hydrazobenzene compounds have very important applications in biology, medicine, materials and industry. Hydrazobenzene compounds are also concerned in the dye field due to their special structure, and therefore, hydrazobenzene compounds are important intermediates in the synthesis of drugs and the dye industry.
[0003] Reduction hydrogenation of azobenzene is one of the classical methods for preparing hydrazobenzene. In general, reduction hydrogenation of azobenzene is mainly carried out by three methods: the first method is to use a large amount of metal reducing agent, such as Na, Zn, Sn, Sm and Mg; the second method is transition metal (Ru and Pd) catalyzed hydrogenation of azobenzene; and the third method is to use main group element catalysts, such as B and P or Bi complexes to promote transfer hydrogenation of azobenzene. However, the above reactions usually have problems such as generation of a large amount of inorganic metal waste, easy pollution of the environment, expensive catalysts, difficult control of reaction temperature and pressure, excessive reduction of azobenzene to aniline, poor functional group tolerance in the reduction process, and toxic hydrogen transfer reagents. SUMMARY
[0004] The application provides a synthesis method of hydrazobenzene and hydrazobenzene to solve the problems of environmental pollution, expensive catalysts, difficult control of reactions, excessive reduction, poor functional group tolerance and toxic hydrogen transfer reagents in the reduction hydrogenation of azobenzene in the prior art.
[0005] In a first aspect, the application provides a synthesis method of hydrazobenzene, which comprises the following steps:
[0006] mixing a boron source and an azobenzene compound under an oxygen-free environment, and adding a catalyst to perform catalytic reaction to obtain a hydrazobenzene compound crude product;
[0007] performing chromatographic purification on the hydrazobenzene compound crude product to obtain a hydrazobenzene compound;
[0008] The catalyst is cobalt chloride, and the boron source is pinacol borane.
[0009] The azobenzene compound has a molecular structure as shown in formula 1.
[0010]
[0011] In formula 1, R1 is hydrogen, methyl, fluorine, trifluoromethyl, ethyl ester; R2 is methyl, chlorine, trifluoromethyl, cyano, ethyl ester.
[0012] The hydrogenated azobenzene compound product has a molecular structure as shown in formula 2.
[0013]
[0014] In formula 2, R1 is hydrogen, methyl, fluorine, trifluoromethyl, ethyl ester; R2 is methyl, chlorine, trifluoromethyl, cyano, ethyl ester.
[0015] Optionally, the molar ratio of the azobenzene compound to the catalyst is ≤10.
[0016] Optionally, the molar ratio of the azobenzene compound to the boron source is ≤0.4.
[0017] Optionally, the molar ratio of the azobenzene compound, the catalyst and the boron source is 1.0:0.1:3.0.
[0018] Optionally, the cobalt chloride includes cobalt chloride monohydrate and / or anhydrous cobalt chloride.
[0019] Optionally, the cobalt chloride is anhydrous cobalt chloride.
[0020] Optionally, the catalytic reaction includes catalytic reaction in an organic solvent, and the organic solvent includes tetrahydrofuran.
[0021] Optionally, the temperature of the catalytic reaction is ≥100℃, and the time of the catalytic reaction is ≥24h.
[0022] Optionally, the oxygen-free environment includes nitrogen.
[0023] In a second aspect, the application provides a hydrogenated azobenzene compound, which is prepared by the synthesis method of the first aspect.
[0024] Compared with the prior art, the above technical solution provided by the embodiments of the application has the following advantages:
[0025] The synthesis method of the hydrazobenzene provided by the embodiment of the application adopts anhydrous cobalt chloride as a catalyst, and pinacol borane as a boron source, and adopts an azobenzene compound as a raw material, so that the pinacol borane and the azobenzene compound can be subjected to a borohydration reaction under the premise of the anhydrous cobalt chloride catalysis, and then the specific structural formula of the azobenzene compound is controlled, so that the azobenzene compound with diversified structures can be synthesized. Since the raw material used in the method is widely sourced, and the overall method is simple to operate, widely applicable, and highly selective, compared with the traditional preparation method of the hydrazobenzene compound, the environmental friendliness and substrate applicability of the method are obviously improved, and the borohydration reaction condition is simple and mild, so that the defects existing in the existing reduction hydrogenation of azobenzene can be solved. BRIEF DESCRIPTION OF DRAWINGS
[0026] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate preferred embodiments of the application and, together with the description, serve to explain the principles of the application.
[0027] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.
[0028] Figure 1 A synthesis method of hydrazobenzene is provided for the embodiment of the application.
[0029] Figure 2 A synthesis method of hydrazobenzene is provided for the embodiment of the application. DETAILED DESCRIPTION
[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the application more clear, the technical solutions in the embodiments of the application will be described clearly and completely in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are a part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.
[0031] Unless otherwise specifically indicated, the various raw materials, reagents, instruments and equipment, etc. used in the application can be purchased from the market or can be prepared by the existing method.
[0032] Figure 1 A synthesis method of hydrazobenzene is provided for the embodiment of the application.
[0033] Figure 2 An exemplary schematic diagram of the actual process of synthesizing azobenzene according to an embodiment of this application is shown;
[0034] like Figure 1 and Figure 2 As shown in the embodiments of this application, a method for synthesizing hydrazine is provided, the method comprising:
[0035] S1. Under anaerobic conditions, a boron source and an azobenzene compound are mixed, and a catalyst is added to carry out a catalytic reaction to obtain a crude product of hydrogenated azobenzene compound;
[0036] S2. The crude hydrazine compound is purified by chromatography to obtain the hydrazine compound;
[0037] The catalyst is cobalt chloride, and the boron source is pinacolborane;
[0038] The azobenzene compounds have the molecular structure shown in Formula 1.
[0039]
[0040] In Formula 1, R1 is hydrogen, methyl, fluoro, trifluoromethyl, or ethyl ester; R2 is methyl, chloro, trifluoromethyl, cyano, or ethyl ester.
[0041] The hydrogenated azobenzene compound products have the molecular structure shown in Formula 2.
[0042]
[0043] In Formula 2, R1 is hydrogen, methyl, fluoro, trifluoromethyl, or ethyl ester; R2 is methyl, chloro, trifluoromethyl, cyano, or ethyl ester.
[0044] It should be noted that the methyl group in R1 and R2 can be 3-methyl, and the methyl group in R1 can also be 4-methyl.
[0045] It should be noted that the fluorine group in the R1 group can be a 2-fluoro group; the trifluoromethyl group in the R1 group can be a 3-fluoro group; and the ethyl ester in the R1 group can be a 4-ethyl ester.
[0046] It should be noted that the chlorine group in the R2 group can be 3-chloro; the trifluoromethyl group in the R2 group can be 4-trifluoromethyl; the cyano group in the R2 group can be 4-cyano; and the ethyl ester in the R2 group can be 4-ethyl ester.
[0047] In some alternative embodiments, the molar ratio of the azobenzene compound to the catalyst is ≤10.
[0048] In some alternative embodiments, the molar ratio of the azobenzene compound and the boron source is ≤0.4.
[0049] In some alternative embodiments, the molar ratio of the azobenzene compound, the catalyst, and the boron source is 1.0:0.1:3.0.
[0050] In the embodiments of this application, by refining the specific molar ratio of azobenzene compounds, catalysts and boron sources, the yield of most hydrazobenzene compound products can be above 80%, thereby obtaining a sufficient number of hydrazobenzene compound products.
[0051] It should be noted that when the molar ratio of catalyst or boron source increases, the yield of the final product remains basically unchanged, but when the molar ratio of catalyst or boron source decreases, the yield of the final product will be affected.
[0052] In some alternative embodiments, the cobalt chloride comprises cobalt chloride monohydrate and / or anhydrous cobalt chloride.
[0053] In some alternative embodiments, the cobalt chloride is anhydrous cobalt chloride.
[0054] In this embodiment, controlling the specific type of cobalt chloride can enhance the catalytic ability of the catalyst by using anhydrous cobalt chloride, so that the reaction between the azobenzene compound and the boron source can completely produce hydrogenated azobenzene compound.
[0055] It should be noted that the reaction can also be carried out using cobalt chloride monohydrate, but the product yield is lower.
[0056] In some alternative embodiments, the catalytic reaction includes a catalytic reaction in an organic solvent, including tetrahydrofuran.
[0057] In this embodiment of the application, by controlling the catalytic reaction to be carried out in tetrahydrofuran, the yield and purity of the final product can be further improved, thereby obtaining a sufficient amount of hydrogenated azobenzene compound products.
[0058] In some alternative embodiments, the temperature of the catalytic reaction is ≥100°C and the time of the catalytic reaction is ≥24h.
[0059] In the embodiments of this application, by controlling the specific temperature and time of the catalytic reaction, sufficient hydroboration reaction can be carried out between pinacol borane and azobenzene compounds under the premise of anhydrous cobalt chloride catalysis, thereby obtaining a sufficient amount of hydrogenated azobenzene compound products; and the reaction conditions are mild and simple.
[0060] It should be noted that both excessively low temperatures and excessively short reaction times will affect the yield of the final product.
[0061] In some alternative implementations, the anaerobic environment includes nitrogen.
[0062] In this embodiment, controlling the specific atmosphere of the oxygen-free environment can maintain the gas pressure for the catalytic reaction on the one hand, and save the cost of the catalytic reaction on the other.
[0063] Based on a general inventive concept, embodiments of this application provide a hydrazine compound, which is prepared by the aforementioned synthesis method.
[0064] The hydrazine compound is prepared based on the above method. The specific steps of the preparation method can be referred to the above embodiments. Since the hydrazine compound adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.
[0065] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards. If there is no corresponding industry standard, then common international standards, conventional conditions, or conditions recommended by the manufacturer are followed.
[0066] Example 1
[0067] like Figure 1 As shown, a method for synthesizing hydrazine is provided, the method comprising:
[0068] S1. Mix 0.3 mmol of p-methylphenyl azo, 0.03 mmol of anhydrous cobalt chloride catalyst and 0.9 mmol of pinacol borane under a nitrogen atmosphere, and carry out the catalytic reaction in 1 mL of tetrahydrofuran to obtain crude hydrazobenzene compounds.
[0069] S2. The crude hydrazobenzene compounds were purified by column chromatography to obtain hydrazobenzene compounds.
[0070] The hydrogenated azobenzene compound product has the molecular structure shown in Formula 3.
[0071]
[0072] The product of this hydrogenated azobenzene compound is 1,2-di-p-toluenehydrazine.
[0073] The catalytic reaction was carried out at a temperature of 100℃ for 24 hours.
[0074] The separation yield of this hydrogenated azobenzene compound product was 86%, and its proton NMR spectral data are as follows:
[0075] 1 HNMR (400MHz, CDCl3) δ7.02 (d, J = 8.0 Hz, 4H), 6.77 (d, J = 8.4 Hz, 4H), 5.51 (s, 2H), 2.26 (s, 6H). 13 C NMR (126MHz, CDCl3) δ146.9,130.0,129.2,112.6,20.6.
[0076] Example 2
[0077] Comparing Example 2 with Example 1, the difference between Example 2 and Example 1 is as follows:
[0078] The azobenzene compounds used are m-methylphenyl azo.
[0079] Hydrogenated azobenzene compounds have molecular structures as shown in Formula 4.
[0080]
[0081] The product of this hydrogenated azobenzene compound is 1,2-di-m-toluenehydrazine.
[0082] The separation yield of this hydrogenated azobenzene compound product was 85%, and its proton NMR spectral data are as follows:
[0083] 1 H NMR (400MHz, CDCl3) δ7.18 (t, J = 7.7Hz, 2H), 6.76–6.71 (m, 6H), 5.57 (s, 2H), 2.36 (s, 6H). 13 C NMR (126MHz, CDCl3) δ 149.2, 139.4, 129.3, 120.9, 113.1, 109.6, 21.7. Example 3
[0084] Comparing Example 3 with Example 1, the difference between Example 3 and Example 1 is as follows:
[0085] Azobenzene compounds use 2-fluorophenyl azo.
[0086] Hydrogenated azobenzene compounds have molecular structures as shown in Formula 5.
[0087]
[0088] The product of this hydrogenated azobenzene compound is 1,2-bis(2-fluorophenyl)hydrazine.
[0089] The separation yield of this hydrogenated azobenzene compound product was 94%, and its 1H NMR spectral data are as follows:
[0090] 1 H NMR (400MHz, CDCl3) δ7.09–6.97 (m, 6H), 6.80 (dt, J = 13.7, 4.8Hz, 2H), 5.86 (s, 2H). 13 C NMR (126MHz, CDCl3) δ151.8, 149.9, 136.7 (d, J = 9.9Hz), 124.9 (d, J = 3.4Hz), 119.8 (d, J = 6.9Hz), 115.2 (d, J = 17.8Hz), 113.8 (d, J = 2.6Hz).
[0091] Example 4
[0092] Comparing Example 4 with Example 1, the difference between Example 4 and Example 1 is as follows:
[0093] The azobenzene compounds used are m-trifluoromethylphenyl azo.
[0094] Hydrogenated azobenzene compounds have molecular structures as shown in Formula 6.
[0095]
[0096] The product of this hydrogenated azobenzene compound is 1,2-bis(3-(trifluoromethyl)phenyl)hydrazine.
[0097] The separation yield of this hydrogenated azobenzene compound product was 96%, and its 1H NMR spectral data are as follows:
[0098] 1 H NMR (400MHz, CDCl3) δ7.35 (t, J = 7.8Hz, 2H), 7.13 (d, J = 8.2Hz, 4H), 7.02 (d, J = 8.8Hz, 2H), 5.82 (s, 2H). 13 C NMR (126MHz, CDCl3) δ 148.8, 132.0 (q, J = 32.0Hz), 130.1, 124.3 (q, J = 272.3Hz), 117.0 (q, J = 3.7Hz), 115.4, 109.0 (q, J = 3.9Hz).
[0099] Example 5
[0100] Comparing Example 5 with Example 1, the difference between Example 5 and Example 1 is as follows:
[0101] The azobenzene compound used is 4,4'-(azo-1,2-diyl)(E)-dibenzoic acid diethyl ester.
[0102] Hydrogenated azobenzene compounds have molecular structures as shown in Formula 7.
[0103]
[0104] The product of this hydrogenated azobenzene compound is 1,2-bis(3-(trifluoromethyl)phenyl)hydrazine.
[0105] The separation yield of this hydrogenated azobenzene compound product was 98%, and its 1H NMR spectral data are as follows:
[0106] 1 H NMR (400MHz, CDCl3) δ7.89 (d, J = 8.7Hz, 4H), 6.79 (d, J = 8.8Hz, 4H), 6.18 (s, 2H), 4.30 (q, J = 7.1Hz, 4H), 1.34 (t, J = 7.1Hz, 6H). 13 C NMR (126MHz, CDCl3) δ166.7,152.2,131.6,122.0,111.3,60.6,14.5.
[0107] Example 6
[0108] Comparing Example 6 with Example 1, the difference between Example 6 and Example 1 is as follows:
[0109] The azobenzene compounds are (E)-1-phenyl-2-(m-tolyl)azo.
[0110] Hydrogenated azobenzene compounds have molecular structures as shown in Formula 8.
[0111]
[0112] The product of this hydrogenated azobenzene compound is 1-phenyl-2-(m-tolyl)hydrazine.
[0113] The separation yield of this hydrogenated azobenzene compound product was 94%, and its 1H NMR spectral data are as follows:
[0114] 1H NMR (400MHz, CDCl3) δ7.42(t,J=7.9Hz,2H),7.31(t,J=7.9Hz,1H),7.05(t,J=7.0Hz,3H),6.88(d,J=1.5Hz,3H),5.72(d,J=11.9Hz,2H),2.49(s,3H). 13 C NMR (125MHz, CDCl3) δ149.1 (d, J = 4.3Hz), 139.4, 129.4 (d, J = 13.7Hz), 120.9, 119.9, 113.1, 112.4, 109.4, 21.7.
[0115] Example 7
[0116] Comparing Example 7 with Example 1, the difference between Example 7 and Example 1 is as follows:
[0117] The azobenzene compounds are (E)-1-(4-chlorophenyl)-2-phenyldiazepine.
[0118] Hydrogenated azobenzene compounds have molecular structures as shown in Formula 9.
[0119]
[0120] The product of this hydrogenated azobenzene compound is 1-(4-chlorophenyl)-2-phenylhydrazine.
[0121] The separation yield of this hydrogenated azobenzene compound product was 96%, and its 1H NMR spectral data are as follows:
[0122] 1 H NMR (400MHz, CDCl3) δ7.33–7.19 (m, 4H), 6.96–6.80 (m, 5H), 5.62 (d, J = 5.9Hz, 2H). 13 C NMR (125MHz, CDCl3) δ148.5,147.6,129.5,129.3,124.4,120.3113.6,112.4.
[0123] Example 8
[0124] Comparing Example 8 with Example 1, the difference between Example 8 and Example 1 is as follows:
[0125] The azobenzene compounds are (E)-1-phenyl-2-(4-(trifluoromethyl)phenyl)azo.
[0126] Hydrogenated azobenzene compounds have molecular structures as shown in Formula 10.
[0127]
[0128] The product of this hydrogenated azobenzene compound is 1-phenyl-2-(4-(trifluoromethyl)phenyl)hydrazine.
[0129] The separation yield of this hydrogenated azobenzene compound product was 96%, and its 1H NMR spectral data are as follows:
[0130] 1 H NMR (400MHz, CDCl3) δ7.33–7.19 (m, 4H), 6.96–6.80 (m, 5H), 5.62 (d, J = 5.9Hz, 2H). 13 C NMR (125MHz, CDCl3) δ148.5,147.6,129.5,129.3,124.4,120.3113.6,112.4.
[0131] Example 9
[0132] Comparing Example 9 with Example 1, the difference between Example 9 and Example 1 is as follows:
[0133] The azobenzene compounds are (E)-4-(phenylazo)benzonitrile.
[0134] Hydrogenated azobenzene compounds have molecular structures as shown in Formula 11.
[0135]
[0136] The product of this hydrogenated azobenzene compound is 4-(2-phenylhydrazinyl)benzonitrile.
[0137] The separation yield of this hydrogenated azobenzene compound product was 82%, and its proton NMR spectrum data are as follows:
[0138] 1 H NMR (400MHz, DMSO) δ8.56 (s, 1H), 7.89 (s, 1H), 7.51 (d, J = 8.1Hz, 2H), 7.13 (t, J = 7.5Hz, 2H), 6.79 (d, J = 8.2Hz, 2H), 6.69 (t, J = 7.4Hz, 3H). 13 C NMR (125MHz, DMSO) δ154.2,149.3,134.0,129.5,120.7,118.9,112.2,111.7,98.3.
[0139] Example 10
[0140] Comparing Example 10 with Example 1, the difference between Example 10 and Example 1 is as follows:
[0141] The azobenzene compound is (E)-4-(phenylazo)benzoic acid ethyl ester.
[0142] Hydrogenated azobenzene compounds have molecular structures as shown in Formula 12.
[0143]
[0144] The product of this hydrogenated azobenzene compound is ethyl 4-(2-phenylhydrazine)benzoate.
[0145] The separation yield of this hydrogenated azobenzene compound product was 86%, and its proton NMR spectral data are as follows:
[0146] 1 H NMR (400MHz, CDCl3) δ7.94 (d, J = 8.7Hz, 2H), 7.25 (t, J = 7.9Hz, 2H), 6.92
[0147] –6.82(m,5H),6.00(s,1H),5.76(s,1H),4.35(q,J=7.1Hz,2H),1.39(t,J=7.1Hz,3H). 13 C NMR (126MHz, CDCl3) δ166.8,152.9,148.2,131.6,129.5,121.6,120.5,112.5,111.2,60.5,14.5.
[0148] In summary, the present application provides a method for synthesizing hydrogenated azobenzene, which involves a hydroboration reaction of azobenzene compounds with pinacolborane in an anhydrous cobalt chloride catalytic system, thereby achieving the synthesis of structurally diverse hydrogenated azobenzene compounds.
[0149] At the same time, this method has good reaction universality and high yield, with most reactions having a yield of over 80%.
[0150] This method is an important supplement to the preparation routes of hydrazobenzene compounds and provides an important idea for the synthesis of hydrazobenzene.
[0151] Furthermore, the catalytic conditions used in this method represent the simplest method for the direct hydroboration of azobenzene compounds to prepare hydrazobenzene compounds, demonstrating significant advantages over other complex catalytic systems.
[0152] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.
[0153] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.
[0154] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A method for synthesizing hydrazine, characterized in that, The synthesis method includes: A boron source and azobenzene compounds were mixed under anaerobic conditions, and a catalyst was added to carry out a catalytic reaction to obtain crude hydrogenated azobenzene compounds. The crude hydrazine compound was purified by chromatography to obtain the hydrazine compound. The catalyst is cobalt chloride, and the boron source is pinacolborane; The azobenzene compounds have the molecular structure shown in Formula 1. Formula 1, In Formula 1, R1 is fluoro, trifluoromethyl, or ethyl ester; R2 is chloro, trifluoromethyl, cyano, or ethyl ester. The hydrogenated azobenzene compound products have the molecular structure shown in Formula 2. Equation 2, In Formula 2, R1 is fluoro, trifluoromethyl, or ethyl ester; R2 is chloro, trifluoromethyl, cyano, or ethyl ester. The molar ratio of the azobenzene compound, the catalyst, and the boron source is 1.0:0.1:3.0; The cobalt chloride is anhydrous cobalt chloride.
2. The synthesis method according to claim 1, characterized in that, The catalytic reaction includes a reaction in an organic solvent, including tetrahydrofuran.
3. The synthesis method according to claim 1 or 2, characterized in that, The temperature of the catalytic reaction is ≥100℃, and the time of the catalytic reaction is ≥24h.
4. The synthesis method according to claim 1, characterized in that, The anaerobic environment includes nitrogen.
Citation Information
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Activation method of bis(pinacolato)diborane and application thereof
CN105503925A