4-nitrobenzoic acid imidazole quaternary ammonium salt as well as preparation method and application thereof

Abstract

The invention discloses 4-nitrobenzoic acid imidazole quaternary ammonium salt as well as a preparation method and application thereof. The structure of the 4-nitrobenzoic acid imidazole quaternary ammonium salt is shown as a formula (I), the 4-nitrobenzoic acid imidazole quaternary ammonium salt is in a single crystal form, the crystal form is a triclinic system and a P-1 space group, and the 4-nitrobenzoic acid imidazole quaternary ammonium salt has a remarkable antibacterial effect and good thermal stability and can be used as an antibacterial agent to be applied to preparation of antibacterial materials. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of antibacterial materials and relates to a 4-nitrobenzoic acid imidazole quaternary ammonium salt and a preparation method and application thereof. Background Art

[0002] Common microorganisms such as Escherichia coli, Candida albicans and Staphylococcus aureus can easily cause functional disorders in the human body and induce diseases, and a considerable number of malignant infectious diseases are caused by microorganisms. Quaternary ammonium salt antimicrobial agents are low-priced and highly practical, and have become one of the most widely used and most promising cationic antimicrobial agents. + With a positive charge, it can rely on Coulomb attraction to adsorb on the cell membrane of negatively charged bacteria, destroy the cell membrane structure, cause the cell contents to flow out, and kill the bacteria. However, due to the extensive use of quaternary ammonium salts, a large number of drug-resistant bacteria have been produced, and the problem of bacterial resistance has become a problem that cannot be ignored. Finding safe, efficient, and residue-free bactericidal drugs is a new development trend. The preparation of quaternary ammonium salts also needs to develop in the direction of increasing efficiency, improving biocompatibility, and expanding the scope of application.

[0003] Mao Huilin prepared an imidazole-m-nitrobenzoic acid eutectic by evaporative crystallization, cooling crystallization and solvent drop grinding method. Its molecular formula is C 10 H9N3O4; the imidazole-m-nitrobenzoic acid eutectic contains three NH···O hydrogen bonds. The carboxyl group in m-nitrobenzoic acid is connected to the NH bond in the imidazole ring, and the OH bond is connected to the N atom in the imidazole ring through NH···O hydrogen bonds. The obtained imidazole-m-nitrobenzoic acid eutectic has a monoclinic crystal system, a P2(1) / c space group, and the unit cell parameters are: α=90.00°,β=106.38(5)°,γ=90.00°,Z=4,unit cell volume The imidazole-m-nitrobenzoic acid cocrystal has certain antibacterial properties, but its antibacterial effect still needs to be improved (Mao Huilin. Preparation and Analysis Research of Drug Cocrystals [D]. Tianjin University, 2009. DOI: 10.7666 / d.y1675622.). Summary of the invention

[0004] The purpose of the present invention is to provide a 4-nitrobenzoic acid imidazole quaternary ammonium salt and a preparation method and application thereof.

[0005] According to one aspect of the present invention, there is provided a quaternary ammonium salt of 4-nitrobenzoic acid imidazole, which has 4-nitrobenzoic acid as anion and imidazole as a cation, and has a chemical structure as shown in formula (I):

[0006]

[0007] The 4-nitrobenzoic acid imidazole quaternary ammonium salt provided by the present invention is as follows Figure 1 As shown, the anion and the cation are connected by 4 CH···O and 1 CH···N hydrogen bonds, wherein the nitro group in 4-nitrobenzoic acid is connected to the imidazole ring through CH···O and CH···N, and the carboxyl group in 4-nitrobenzoic acid is connected to the imidazole ring through CH···O, with a total of 5 hydrogen bonds; the obtained 4-nitrobenzoic acid imidazole quaternary ammonium salt is in single crystal form, the crystal form is triclinic system, P-1 space group, and the unit cell parameters are: α=103.033(4)°,β=100.165(5)°,γ=90.725(5)°,Number of molecules in the unit cell Z=2,Unit cell volume

[0008] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned 4-nitrobenzoic acid imidazole quaternary ammonium salt, comprising the following steps:

[0009] Take 4-nitrobenzoic acid and imidazole, dissolve them in the first solvent, react at room temperature for 2 to 6 hours, filter under reduced pressure, wash the filter residue with the first solvent and dry it to obtain a white solid powder reaction product A;

[0010] The reaction product A is dissolved in the second solvent, left at room temperature for 1 to 3 weeks, filtered under reduced pressure, and the filter residue is washed with the second solvent and then dried to obtain a colorless crystalline material, which is the 4-nitrobenzoic acid imidazole quaternary ammonium salt of the present invention.

[0011] In some embodiments, the molar ratio of 4-nitrobenzoic acid to imidazole may be 1:(0.8-1.2).

[0012] In some embodiments, the first solvent may be selected from at least one of methanol, ethanol, chloroform, isopropanol, and acetone. Preferably, the first solvent is methanol.

[0013] In some embodiments, the second solvent may be selected from at least one of methanol, ethanol, chloroform, isopropanol, and acetone. Preferably, the second solvent is methanol.

[0014] In some embodiments, the molar volume ratio of the reaction product A to the second solvent may be (2-5) mmol: (10-15) mL.

[0015] In some embodiments, the drying method may be vacuum drying, which may specifically include the following steps: placing the material to be dried in a vacuum drying oven, and drying it at 0.08-0.1 MPa and 45-60° C. for 10-15 hours.

[0016] The preparation method of 4-nitrobenzoic acid imidazole quaternary ammonium salt provided by the invention can be carried out at room temperature throughout the whole process, and is simple to operate and has a high yield; the required instruments and equipment are simple and easy to operate; the required solvent consumption is small, the cost is saved, and it is conducive to industrial production.

[0017] The beneficial effects of the present invention include:

[0018] The preparation method of 4-nitrobenzoic acid imidazole quaternary ammonium salt provided by the invention can be carried out at room temperature throughout the whole process, and has simple reaction conditions, fast reaction speed, simple operation and low cost. The prepared 4-nitrobenzoic acid imidazole quaternary ammonium salt has significant antibacterial effect and good thermal stability, and can be used as an antibacterial agent and widely used in preparing various antibacterial materials.

[0019] In addition, the absorption cutoff wavelength of the 4-nitrobenzoic acid composite quaternary ammonium salt provided by the present invention is 421nm, and the corresponding optical band gap is 2.95eV, indicating that it has a certain absorption capacity for visible light. Its corresponding optical band gap belongs to the range of typical semiconductor materials, which is equivalent to the value of other organic nonlinear optical materials studied as potential solar ultraviolet absorbers, and can be used as an ultraviolet absorber. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the hydrogen bond diagram of 4-nitrobenzoic acid imidazolium quaternary ammonium salt of the present invention;

[0021] Figure 2 Schematic diagram of the crystal structure of 4-nitrobenzoic acid imidazolium quaternary ammonium salt of the present invention;

[0022] Figure 3 is the cationic mass spectrum of the quaternary ammonium salt of 4-nitrobenzoic acid imidazolium of the present invention;

[0023] Figure 4 is the negative ion mass spectrum of 4-nitrobenzoic acid imidazolium quaternary ammonium salt of the present invention;

[0024] Figure 5 is the infrared spectrum of 4-nitrobenzoic acid imidazole quaternary ammonium salt of the present invention;

[0025] Figure 6 It is a solid ultraviolet-visible diffuse reflectance spectrum of 4-nitrobenzoic acid imidazolium quaternary ammonium salt of the present invention;

[0026] Figure 7 is the energy gap diagram of 4-nitrobenzoic acid imidazolium quaternary ammonium salt of the present invention;

[0027] Figure 8 It is a thermogravimetric-thermal differential analysis diagram of 4-nitrobenzoic acid imidazole quaternary ammonium salt of the present invention;

[0028] Fig. 9The diagram is the inhibition zone of 4-nitrobenzoic acid imidazole quaternary ammonium salt and solvent DMSO against Staphylococcus aureus and Escherichia coli;

[0029] Fig.10 The MIC determination graph of the 4-nitrobenzoic acid composite quaternary ammonium salt ([IM][4NO2BA]), 4-nitrobenzoic acid (4NO2BA), imidazole (IM), and imidazole-m-nitrobenzoic acid eutectic (IM-m-nitrobenzoic acid) of the present invention against Staphylococcus aureus and Escherichia coli. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the embodiments. The examples are only for explanation and are not intended to limit the present invention in any way. Unless otherwise specified, the raw materials and reagents used in the examples are conventional products that can be obtained commercially; the experimental methods in the examples where specific conditions are not specified are usually carried out according to conventional conditions in the art or according to the conditions recommended by the manufacturer.

[0031] Example 1

[0032] The preparation method of 4-nitrobenzoic acid imidazole quaternary ammonium salt comprises the following steps:

[0033] (1) Weigh 2 mmol of 4-nitrobenzoic acid and 2 mmol of imidazole into a 30 mL wide-mouth bottle, add 20 mL of methanol to dissolve, stir and react at room temperature for 6 hours, a white precipitate is generated, and the precipitate is filtered under reduced pressure, washed with a small amount of methanol three times, and vacuum dried at 0.08 MPa and 60° C. for 12 hours to obtain a white solid powder as the reaction product A;

[0034] (2) 2 mmol of the above reaction product A was placed in a 50 mL beaker, 15 mL of methanol was added as a solvent, and the reaction product A was fully dissolved. The solution was then placed at room temperature for natural evaporation. After one week, colorless crystals were precipitated. The crystals were filtered under reduced pressure, washed with a small amount of methanol for 3 times, and vacuum dried at 0.08 MPa and 60° C. for 12 h to obtain 4-nitrobenzoic acid imidazole quaternary ammonium salt. The crystal structure diagram is shown in FIG. Figure 2 The main crystallographic data are shown in Table 1.

[0035] Table 1 Main crystallographic data of 4-nitrobenzoic acid imidazole quaternary ammonium salt of the present invention

[0036]

[0037] The electrospray mass spectrometer of 4-nitrobenzoic acid imidazole quaternary ammonium salt ([IM][4NO2BA]) prepared by the present invention is as follows: Figures 3-4 As shown in the figure, it can be seen that the cation [IM] + The measured molecular weight is 69.2, which is consistent with the theoretical value of 68.0. The anion [4NO2BA]- The measured molecular weight is 166.0, which is close to the theoretical value of 166.2.

[0038] The infrared spectrum of 4-nitrobenzoic acid composite quaternary ammonium salt is shown in Figure 5 , 3167cm -1 The absorption peak near 3097cm is caused by the NH stretching vibration on the imidazole ring; -1 and 3008cm -1 It is mainly the stretching vibration of CH of the five-membered heterocyclic imidazole ring; at 1712 cm -1 The absorption peak near is the stretching vibration of C=O in carboxylic acid; 1554cm -1 The absorption peaks near 1514cm -1 and 1342cm -1 The absorption peaks near 1187cm belong to the asymmetric stretching vibration and symmetric stretching vibration of the nitro NO2 group on the benzene ring; -1 and 1104cm -1 The absorption peaks near 764cm are caused by the in-plane bending vibration of the CH of the benzene ring; -1 and 702cm -1 The nearby absorption peaks all belong to the CH out-of-plane bending vibration of the benzene ring.

[0039] The solid UV absorption spectrum of 4-nitrobenzoic acid composite quaternary ammonium salt was tested. The solid UV-visible diffuse reflectance spectrum and energy gap diagram are shown in Figure 6 and Figure 7 As can be seen from the figure, the absorption cutoff wavelength of the 4-nitrobenzoic acid composite quaternary ammonium salt provided by the present invention is 421nm, and the corresponding optical band gap is 2.95eV, indicating that the 4-nitrobenzoic acid composite quaternary ammonium salt provided by the present invention has a certain absorption capacity for visible light. This band gap belongs to the range of typical semiconductor materials and is comparable to the values ​​of other organic nonlinear optical materials studied as potential solar ultraviolet absorbers, indicating that it is a potential optical material.

[0040] Thermogravimetric analysis and thermal differential analysis (TG / DTG) for the detection of 4-nitrobenzoic acid complex quaternary ammonium salt, see Figure 8 . From the TG curve, from room temperature to the starting point of weight loss, as the temperature increases, the compound loses a small amount of weight, the main weight loss stage is between 168.4 and 257.1°C, and the weight loss rate is 97.06% of the initial mass. When the temperature reaches 799.1°C, the residual mass of the measured material is 2.94%. According to the TG / DTG curve, the 4-nitrobenzoic acid composite quaternary ammonium salt provided by the present invention is stable at 168.4°C, showing strong thermal stability.

[0041] Test example: Antibacterial test

[0042] (1) Determination of antibacterial activity

[0043] Take an appropriate amount of 4-nitrobenzoic acid composite quaternary ammonium salt crystals prepared in Example 1 and dissolve them in dimethyl sulfoxide (DMSO) to make 0.1 g mL -1 Take a 6mm diameter round filter paper and soak it in the solution for later use. At the same time, take a 6mm diameter round filter paper and soak it in DMSO as a blank control. 6 CFU·mL -1 Staphylococcus aureus bacterial suspension and 100 μL of 2.0×10 7 CFU·mL -1 The E. coli bacterial solution was evenly spread on the LB solid medium, and then the filter paper soaked in the drug solution / DMSO was placed on the medium, and the culture dish was sealed with a sealing film. After constant temperature cultivation at 37°C for 24 hours, the diameter of the inhibition zone was measured. The results are shown in Fig. 9 .

[0044] The results showed that the sizes of the inhibition zones of the 4-nitrobenzoic acid composite quaternary ammonium salt provided by the present invention against Staphylococcus aureus and Escherichia coli were 1.4 cm and 1.3 cm, respectively. It can be seen that at the same dosage, the 4-nitrobenzoic acid composite quaternary ammonium salt exhibited good antibacterial activity against Staphylococcus aureus and Escherichia coli.

[0045] (2) Minimum inhibitory concentration (MIC) determination

[0046] Referring to the "evaporation crystallization" method described in "Mao Huilin. Preparation and Analysis of Drug Cocrystals [D]. Tianjin University, 2009. DOI: 10.7666 / d.y1675622.", imidazole-m-nitrobenzoic acid cocrystals were prepared using deionized water as solvent, and their MICs against Escherichia coli and Staphylococcus aureus were determined.

[0047] The MIC value was determined by the two-fold dilution method. First, 100 μL of LB liquid culture medium was transferred to the required wells of the 96-plate, and then 4-nitrobenzoic acid complex quaternary ammonium salt ([IM][4NO2BA]), 4-nitrobenzoic acid (4NO2BA), imidazole (IM), and imidazole-m-nitrobenzoic acid eutectic (IM-m-nitrobenzoic acid) were dissolved in DMSO to a concentration of 0.01 mol·L -1 100 μL of the drug solution was added to the first well on the left side of each row of the 96-well plate. Then, the two-fold dilution method was used. After gradient dilution, 100 μL of a 6.0×10 6 CFU·mL -1 of Staphylococcus aureus (or 100 μL at a concentration of 2.0 × 10 7 CFU·mL-1 coli), with 3 parallel groups for each sample. A negative control (adding bacterial solution and kanamycin), a positive control (adding only bacterial solution), a solvent control (adding bacterial solution and solvent DMSO), and a blank control (adding only LB medium) were also set up. After culturing in a 37°C incubator for 18 h, 50 μL of 2 g·L -1 2,3,5-triphenyltetrazolium chloride (TTC) was added and allowed to stand for 1 hour for color development. The minimum concentration at which no red color was observed was the minimum inhibitory concentration of the sample, see Table 2. Fig.10 .

[0048] Table 2 MIC values ​​of each sample

[0049]

[0050] The results show that the 4-nitrobenzoic acid composite quaternary ammonium salt provided by the present invention has a more significant antibacterial effect.

[0051] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. 4-nitrobenzoic acid imidazole quaternary ammonium salt having the structure shown in the following formula (I):

2. 4-nitrobenzoic acid imidazole quaternary ammonium salt according to claim 1, characterized in that, The 4-nitrobenzoic acid imidazolium quaternary ammonium salt is in the form of a single crystal, and its crystal form is a triclinic system, a P-1 space group, and the unit cell parameters are: α=103.033(4)°, β=100.165(5)°, γ=90.725(5)°, Z=2, 3. The preparation method of 4-nitrobenzoic acid imidazole quaternary ammonium salt according to claim 1 or 2, characterized in that, The steps include: Take 4-nitrobenzoic acid and imidazole, dissolve them in a first solvent, react at room temperature for 2 to 6 hours, filter under reduced pressure, wash the filter residue with the first solvent and dry it to obtain a reaction product A; The reaction product A is dissolved in the second solvent, left to stand at room temperature for 1 to 3 weeks, filtered under reduced pressure, and the filter residue is washed with the second solvent and then dried to obtain the product.

4. The preparation method according to claim 3, characterized in that: The molar ratio of the 4-nitrobenzoic acid to imidazole is 1:(0.8-1.2).

5. The preparation method according to claim 3 or 4, characterized in that: The first solvent is selected from at least one of methanol, ethanol, chloroform, isopropanol and acetone.

6. The preparation method according to claim 5, characterized in that: The second solvent is selected from at least one of methanol, ethanol, chloroform, isopropanol and acetone.

7. The preparation method according to claim 6, characterized in that: The molar volume ratio of the reaction product A to the second solvent is (2-5) mmol: (10-15) mL.

8. The preparation method according to claim 3, characterized in that: The drying is vacuum drying.

9. The use of 4-nitrobenzoic acid imidazole quaternary ammonium salt as an antibacterial agent according to claim 1 or 2.

10. The use of 4-nitrobenzoic acid imidazole quaternary ammonium salt as a UV absorber according to claim 1 or 2.

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