A pyrazole derivative, and a preparation method and application thereof
By preparing polydentate pyrazole derivatives that coordinate with metal ions, the problem of single coordination sites of monodentate ligands has been solved, resulting in compounds with rich coordination forms and diverse functions, exhibiting good fluorescence, photoelectric and catalytic properties, and suitable for industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING UNIV OF TECH
- Filing Date
- 2025-01-16
- Publication Date
- 2026-06-19
AI Technical Summary
In the existing technology, monodentate ligands have a single coordination site and a simple coordination mode, resulting in complexes with limited structure and function.
By employing a method for preparing multidentate pyrazole derivatives, compounds with different angles, shapes, and coordination numbers are formed by designing pyrazole derivatives at different positions to coordinate with metal ions. Complex hydrogen bonds are formed by the nitrogen-hydrogen bonds on the pyrazole and protons are released under certain conditions, thus achieving dual coordination sites.
The prepared pyrazole derivatives exhibit abundant coordination sites and multifunctionality in coordination chemistry and catalysis, possessing excellent fluorescence, photoelectric, and catalytic properties. They are simple to operate, low in cost, and suitable for industrial production.
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Figure CN119874672B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of pyrazole derivative technology, and in particular to a pyrazole derivative, its preparation method and application. Background Technology
[0002] Pyrazole derivatives, assembled into bimetallic or heterometallic organopolymers, have attracted increasing interest from chemists due to their tunable chemical and physical properties, exhibiting excellent selectivity or resistance to deactivation. Further research has revealed that these novel homometallic and heterometallic organopolymers demonstrate excellent synergistic catalytic effects in nitro reduction reactions, showing promising application prospects and academic value. In recent years, the design and synthesis of pyrazole derivative compounds with excellent and unique properties has become one of the important research directions in the field of chemistry.
[0003] In existing technologies, monodentate ligands are typically used. However, these ligands have limited coordination sites and simple coordination patterns, resulting in complexes with limited structure and function. Therefore, there is an urgent need for a multifunctional ligand that can provide a wider range of coordination sites to obtain pyrazole derivative compounds with rich coordination patterns, diverse functions, and outstanding performance. Summary of the Invention
[0004] The purpose of this invention is to provide a pyrazole derivative, its preparation method and application, which solves the problems of single coordination sites and simple coordination forms of monodentate ligands in the prior art, resulting in simple structure and function of the complexes.
[0005] To achieve the above objectives, the present invention provides a method for preparing pyrazole derivatives, comprising the following steps:
[0006] S1. Dissolve the reactants in the reaction solution according to the proportion, and then carry out the reflux reaction under N2 atmosphere;
[0007] S2. After extraction, drying, and chromatography, solid product a is obtained;
[0008] S3. Add the solid product a from S2 to a mixed solvent of methanol and dichloromethane. Add HCl to the mixed solvent to remove the protecting group. Then adjust the pH of the mixed solvent to 7. After filtration, obtain the solid product b.
[0009] S4. Add methanol to solid product b from S3 for recrystallization, filter, and vacuum dry to obtain pyrazole derivatives.
[0010] Preferably, S1 is as follows:
[0011] 1,4-Diethynylbenzene, bis(triphenylphosphine)palladium dichloride, and 4-iodo-(1-pyran)pyrazole were dissolved in a mixed solution of triethylamine and tetrahydrofuran, and the solution was heated under N2 atmosphere and refluxed at 70°C for 24 h.
[0012] Preferably, the molar ratio of 1,4-diethynylbenzene, bis(triphenylphosphine)palladium dichloride, and 4-iodo-(1-pyran)pyrazole is 4:1:8;
[0013] The molar volume ratio of the 1,4-diethynylbenzene to the mixed solution of triethylamine and tetrahydrofuran is 1 mmol: 5 mL.
[0014] Preferably, the volume ratio of triethylamine to tetrahydrofuran is 1:1.
[0015] Preferably, S1 is as follows:
[0016] Methyl 3-bromobenzoate, 1-THP-4-pyrazoleboronic acid ester, K2CO3, and tetra-triphenylphosphine palladium were dissolved in a 1,4-dioxane solution and reacted at 110°C for 24 h under a N2 atmosphere.
[0017] Preferably, the molar ratio of methyl 3-bromobenzoate, 1-THP-4-pyrazoleboronic acid ester, and K2CO3 is 20:40:30:1;
[0018] The molar volume ratio of methyl 3-bromobenzoate to 1,4-dioxane is 1 mmol: 5 mL.
[0019] Preferably, in step S3, the volume ratio of the methanol and dichloromethane mixed solvent is 1:1;
[0020] The concentration of HCl is 2 mol / L.
[0021] Preferably, in step S2, the extraction is performed using CHCl3;
[0022] The chromatography used an eluent consisting of ethyl acetate and dichloromethane in a volume ratio of 20:1.
[0023] To achieve the above objectives, the present invention also provides a pyrazole derivative, including pyrazole derivative I and pyrazole derivative II, wherein the structural formula of pyrazole derivative I is as follows:
[0024]
[0025] The structural formula of pyrazole derivative II is as follows:
[0026]
[0027] To achieve the above objectives, the present invention also provides an application of pyrazole derivatives in coordination chemistry and catalysis.
[0028] Therefore, the present invention employs the above-mentioned pyrazole derivative, its preparation method, and its application, and the beneficial effects are as follows:
[0029] (1) The pyrazole derivatives prepared in this invention have different coordination angles at different positions. By design, they can coordinate with different metal ions to form compounds with different angles, shapes and coordination numbers. They can be applied in the fields of coordination chemistry and catalysis to obtain materials with good fluorescence, photoelectric and catalytic properties.
[0030] (2) The pyrazole derivatives prepared in this invention are a class of multifunctional ligands (organic bridged ligands) that can provide a rich number of coordination sites. On the one hand, there are complex hydrogen bonds in the ligands. The hydrogen bonds are formed by nitrogen-hydrogen bonds on the pyrazole ligands, and different conformations are produced by different positions of the hydrogen bonds. On the other hand, the nitrogen-hydrogen bonds are weakly acidic and will dissociate and release protons under certain conditions. The nitrogen atom after releasing the proton can also participate in coordination, that is, it has two coordination sites.
[0031] (3) The preparation method of the present invention only involves organic synthesis, which is simple to operate, has low production cost, cheap and readily available raw materials, and has a yield of more than 75%. The purification is simple and suitable for industrial production.
[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0033] Figure 1 This is the UV-Vis spectrum of 4-nitrophenol before and after the addition of NaBH4 in this invention;
[0034] Figure 2 The UV-Vis spectrum of the assembly of complex I in 4-nitrophenol as a catalyst is shown in this invention.
[0035] Figure 3 It is the -ln(C) of 4-nitrophenol in the assembly of complex I of this invention. t / C0) changing over time;
[0036] Figure 4 This is a cyclic experimental diagram of the catalytic reduction of 4-nitrophenol by the assembly of this invention. Detailed Implementation
[0037] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.
[0038] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.
[0039] Example 1
[0040] The structural formula of pyrazole derivative I is as follows:
[0041]
[0042] Its synthetic route is as follows:
[0043]
[0044] Its preparation method is as follows:
[0045] 1,4-Diethynylbenzene (4 mmol), bis(triphenylphosphine)palladium dichloride (1 mmol), and 4-iodo-(1-pyran)pyrazole (8 mmol) were dissolved in 20 mL of a mixed solution of triethylamine and tetrahydrofuran. The solution was heated under reflux at 70 °C for 24 hours in a N2 atmosphere, extracted with CHCl3, dried, and chromatographically separated to give solid product a (compound of formula I).
[0046] Solid product a was added to a mixed solvent of 20 mL methanol and 20 mL dichloromethane. 1 mL of 2 mol / L HCl was added to the mixed solvent to remove the protecting group. NaHCO3 was added to adjust the pH of the mixed solvent to 7. After filtration, solid product b was obtained. A large amount of methanol was added to solid product b for recrystallization. After filtration and vacuum drying, 850 mg of pyrazole derivative I was obtained (yield: 85%).
[0047] Example 2
[0048] The structural formula of pyrazole derivative II is as follows:
[0049]
[0050] Its synthetic route is as follows:
[0051]
[0052] Its preparation method is as follows:
[0053] Methyl 3-bromobenzoate (4 mmol), 1-THP-4-pyrazoleboronic acid ester (8 mmol), K2CO3 (6 mmol), and tetra-triphenylphosphine palladium (0.4 mmol) were dissolved in 20 mL of 1,4-dioxane solution. The mixture was heated under reflux at 110 °C for 24 hours in a N2 atmosphere, extracted with CHCl3, dried, and chromatographically separated to obtain solid product a (compound of formula II).
[0054] Solid product a was added to a mixed solvent of 20 mL methanol and 20 mL dichloromethane. 1 mL of 2 mol / L HCl was added to the mixed solvent to remove the protecting group. NaHCO3 was added to adjust the pH of the mixed solvent to 7. After filtration, solid product b was obtained. A large amount of methanol was added to solid product b for recrystallization. After filtration and vacuum drying, 660 mg of pyrazole derivative II was obtained (yield: 75%).
[0055] Test
[0056] The nuclear magnetic resonance analysis results of the pyrazole derivatives prepared in Examples 1 and 2 are as follows:
[0057] Example 1:
[0058] 1H NMR (400MHz, DMSO) δ = 13.33 (s, 1H), 8.58 (s, 1H), 8.02 (s, 1H), 7.44 (s, 1H).
[0059] Example 2:
[0060] 1H NMR (DMSO-d6, 400MHz): δ = 13.02 (s, 2H), 8.13 (d, J = 7.6Hz, 3H), 7.86 (d, J = 7.9Hz, 1H), 7.75 (d, J = 7.8Hz, 1H), 7.47 (t, J = 7.7Hz, 1H).
[0061] This indicates that all compounds were successfully synthesized. The nitrogen on the pyrazole and the nitrogen on the pyridine in pyrazole-pyridine ligands have good coordination ability with metals; therefore, supramolecular structures are obtained through coordination with metals.
[0062] Specifically, the pyrazole derivative I prepared in Example 1 was assembled with [(bpy)2Pd2(NO3)2](NO3)2, and the specific operation is as follows:
[0063] Pyrazole derivative I (0.04 mmol, 6.76 mg) and [(bpy)2Pd2(NO3)2](NO3)2 (0.06 mmol, 23.20 mg) were dissolved in 1 mL of DMSO-d6 and assembled at room temperature to obtain complex I. The assembly was monitored by 1H NMR spectroscopy.
[0064] The nuclear magnetic resonance analysis results of complex I are as follows:
[0065] 1 H NMR (600MHz, DMSO) δ = 9.21 (d, J = 6.8Hz, 4H), 8.80 (d, J = 9.4Hz, 2H), 8.76 (d, J = 9.4Hz, 4H), 8.52 (dd, J = 17.2, 9.2Hz, 6H), 8.48 (d, J = 5.0Hz, 4H), 8.29 (d, J = 6.9Hz, 4H), 7.88-7.79 (m, 8H), 7.76 (t, J = 7.2Hz, 2H), 7.56 (d, J = 5.8Hz, 2H).
[0066] Nitro reduction catalysis experiments were conducted on the assemblies of complex I.
[0067] Due to the highly dispersed nature and good catalytic performance of palladium ions, the nitrobenzene reduction reaction was chosen as a model reaction to evaluate the intrinsic relationship between the assembly of complex I and its catalytic activity. Specifically, the reduction process was monitored using ultraviolet-visible absorption spectroscopy (UV-vis).
[0068] The reduction of 4-nitrophenol (4-NP) was investigated using a SHIMADZU UV-2600UV-Vis spectrophotometer. In a cuvette, 30 μl / 10 mM nitrophenol in 3 mL of deionized water was added to a 0.16 mL / 0.1 M NaBH4 solution, followed by 1 mg of an aqueously dispersed nanoscale assembly of synthetic complex I. The solution color gradually changed from bright yellow to transparent over time. Spectroscopic measurements were taken to observe the change over time. Kinetic data were calculated using a pseudo-first-order rate equation.
[0069] The change in absorbance of 4-nitrophenol before and after the addition of NaBH4 is as follows: Figure 1 As shown in the figure, the wavelength shifts significantly after the addition of NaBH4.
[0070] The changes in absorbance after adding the assembly of complex I to 4-nitrophenol as a catalyst are as follows: Figure 2 As shown, the absorbance at 400 nm gradually decreases, while the absorbance at 200-300 nm gradually increases, indicating that 4-nitrophenol is gradually reduced to 4-aminophenol.
[0071] 4-Nitrophenol in the presence of the assembly of complex I -ln(C t The curve of / C0) changing with time is as follows: Figure 3 As shown in Figure C. t C represents the concentration of NPs at time t, and C0 represents the initial concentration of nitrophenol at t=0. t / C0 is determined by the relative absorption intensity (A) t The reaction rate catalyzed by the assembly of this complex I was determined to be K = 1.4370 min. -1 .
[0072] To test the cyclic stability of the assembly of complex I, cyclic experimental conditions were performed. 4-NP (0.1*10) dissolved in 10 μL of 0.2 M NaBH4 was used. -3 mmol) was added to the assembly (Pd 1.05*10 -5 A mixed solution of 0.2 M NaBH4 (mmol) and 0.2 M NaBH4 aqueous solution (2.3 mL) was prepared in a quartz test tube. Figure 4 As shown, the cycle stability is good.
[0073] Therefore, the present invention uses the above-mentioned pyrazole derivative and its preparation method and application to solve the problems of single coordination sites, simple coordination forms, and single structure and function of the obtained complexes in the prior art.
[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for preparing a pyrazole derivative, characterized by, Includes the following steps: S1. Dissolve 1,4-diethynylbenzene, bis(triphenylphosphine)palladium dichloride, and 4-iodo-(1-pyran)pyrazole in a mixed solution of triethylamine and tetrahydrofuran according to the proportion, and then carry out the reaction under reflux under N2 atmosphere; S2, after extraction, drying and chromatography, solid product a is obtained ; S3, adding the solid product a of S2 into a mixed solvent of methanol and dichloromethane, adding HCl to the mixed solvent to remove the protecting group, then adjusting the pH of the mixed solvent to 7, and filtering to obtain a solid product b ; S4. Add methanol to solid product b from S3 for recrystallization, filter, and vacuum dry to obtain pyrazole derivatives. ; In S1, the molar ratio of 1,4-diethynylbenzene, bis(triphenylphosphine)palladium dichloride and 4-iodo-(1-pyran)pyrazole is 4:1:8; The molar volume ratio of the 1,4-diethynylbenzene to the mixed solution of triethylamine and tetrahydrofuran is 1 mmol: 5 mL.
2. The method for preparing a pyrazole derivative according to claim 1, characterized in that, In S1, the heating and reflux reaction specifically involves: Heating and refluxing at 70°C for 24 hours under N2 atmosphere.
3. The method for preparing a pyrazole derivative according to claim 1, characterized in that: The volume ratio of triethylamine to tetrahydrofuran in the mixed solution is 1:
1.
4. The method for preparing a pyrazole derivative according to claim 1, characterized in that, In S3, the volume ratio of the methanol and dichloromethane mixed solvent is 1:1; The concentration of HCl is 2 mol / L.
5. The method for preparing a pyrazole derivative according to claim 1, characterized in that, In S2, the extraction is performed using CHCl3; The chromatography used an eluent consisting of ethyl acetate and dichloromethane in a volume ratio of 20:
1.
6. The application of a pyrazole derivative I in nitro reduction catalysis, characterized in that, The structural formula of the pyrazole derivative I is as follows: .