A 2-imidazolidinone-modified chitosan derivative and its preparation method and application

Abstract

The present invention relates to a chitosan derivative modified with 2-imidazolinone, and a preparation method and application thereof. The present invention adopts a strongly electrophilic isothiocyanate reagent to react with the 2-amino group of chitosan to construct an imidazolinone ring under heating conditions, and has the advantages of high yield and simple operation. The prepared chitosan derivative modified with 2-imidazolinone ring has good water solubility and has good anti-Escherichia coli activity after enzyme degradation.

Description

Technical Field

[0001] The invention relates to the technical field of antibacterial materials, and in particular to a 2-imidazolidinone-modified chitosan derivative and a preparation method and application thereof. Background Art

[0002] Antibacterial materials are widely present in the natural environment and in people's daily life. They are functional materials with bactericidal or antibacterial capabilities. In addition to being divided into inorganic and organic antibacterial materials, antibacterial materials can also be viewed from the perspective of artificial synthesis, and divided into natural antibacterial materials and synthetic antibacterial materials. At present, the research and development of new antibacterial materials that are environmentally friendly, durable, broad-spectrum, and highly effective have been unanimously recognized by all sectors of society and have become a hot research direction in the industry.

[0003] Imidazolinone compounds are an important class of heterocyclic compounds. In the 1990s, the French company Rhone-Poulenc-Aigfor discovered the imidazolinone fungicide fenamidone (1, RPA-407213)23' for the first time when studying 2-methylthioimidazolinone derivatives. In field experiments, the compound has contact, penetration, and systemic activity, showing good protective and therapeutic activity, especially for downy mildew and blight caused by oomycetes, which are difficult to control. Studies on the fungicidal mechanism of fenamidone show that it is a new type of mitochondrial respiration inhibitor with a unique mode of action, a broad fungicidal spectrum, and is particularly effective against resistant strains, which has attracted much attention. Since then, many new imidazolinone fungicides have been reported at home and abroad, all of which have good antibacterial activity, among which 5-arylmethyleneimidazolinone derivatives are particularly outstanding (CN200510019144.2, CN200510019145.7). However, the compounds with excellent fungicidal activity in this class have the disadvantages of long synthesis route, low total yield and poor water solubility. Summary of the invention

[0004] The present invention provides a chitosan derivative modified with 2-imidazolinone, and a preparation method and application thereof. An isothiocyanate reagent with strong electrophilicity is used to react with the 2-amino group of chitosan to construct an imidazolinone ring under heating conditions. The introduction of the sugar ring can enhance the water solubility of the compound, and has the advantages of high yield and simple operation. The prepared chitosan derivative modified with 2-imidazolinone ring has good anti-Escherichia coli activity after enzyme degradation.

[0005] The present invention solves the above technical problems as follows: a chitosan derivative modified with 2-imidazolidinone, the structural formula of which is:

[0006]

[0007] Among them, Ar=Ph,4-CH3O-Ph,4-CH3-Ph,4-F-Ph,4-Cl-Ph,4-Br-Ph, n=11-500.

[0008] The synthesis route of the above-mentioned 2-imidazolidinone-modified chitosan derivative is as follows:

[0009]

[0010] Wherein, Ar=Ph,4-CH3O-Ph,4-CH3-Ph,4-F-Ph,4-Cl-Ph,4-Br-Ph,n=11-500;

[0011] The synthesis steps are:

[0012] a) Compound 1 is dissolved in a first solvent, carbon disulfide is added, reacted at 50-70° C. for 24-36 hours, cooled to room temperature, concentrated under reduced pressure, recrystallized to precipitate a solid, filtered, and the mother liquor is concentrated under reduced pressure to evaporate the solvent to obtain Compound 2.

[0013] b) Compound 3 is dissolved in a second solvent, and compound 2 is added at room temperature, stirred at 80-100° C. for 24-72 hours, cooled to room temperature, concentrated under reduced pressure, filtered, dried, dialyzed, and freeze-dried to obtain compound I.

[0014] Preferably, in step a), the molar ratio of compound 1 to carbon disulfide is 1:10-15.

[0015] Preferably, in step a), the first solvent is dichloromethane, acetonitrile or a mixture of the two.

[0016] Preferably, in step a), the reaction temperature is 60° C. and the reaction time is 24 h.

[0017] Preferably, in step b), the molar ratio of compound 2 to compound 3 is 1:1-1.5.

[0018] Preferably, in step b), the second solvent is acetonitrile, N,N-dimethylformamide or a mixture of two thereof.

[0019] Preferably, in step b), the reaction temperature is 80° C. and the reaction time is 72 h.

[0020] The use of the chitosan derivative modified with 2-imidazolidinone as described above in antibacterial materials has an antibacterial rate of 80-90% against Escherichia coli.

[0021] The invention has the beneficial effects that: the invention adopts a strongly electrophilic isothiocyanate reagent to react with the 2-amino group of chitosan to construct an imidazolinone ring under heating conditions, and the imidazolinone ring has an aromatic ring substituent, which can further improve the antibacterial effect. The invention has simple synthesis operation, mild conditions, high yield, and the prepared chitosan derivative modified with the 2-imidazolinone ring has good water solubility and has good anti-Escherichia coli activity after enzyme degradation.

[0022] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 The structural formula diagram of the chitosan derivative modified with 2-imidazolidinone provided by the present invention;

[0025] Figure 2 The invention provides a synthetic circuit diagram of a chitosan derivative modified with 2-imidazolidinone. DETAILED DESCRIPTION

[0026] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0027] Example 1

[0028] The synthesis route of compound I-1 is as follows:

[0029]

[0030] The synthesis steps are as follows:

[0031] a) Preparation of compound 2-1: Weigh compound 1-1 (451.5 mg, 1 mmol) and dissolve it in dry acetonitrile, add 0.6 mL of carbon disulfide, stir at 60°C for 24 hours, evaporate the solvent under reduced pressure, add ethyl acetate / petroleum ether (volume ratio of 1:4) for recrystallization, filter, and evaporate the mother liquor under reduced pressure to obtain a light yellow solid compound 2-1 (186.8 mg, yield 80.1%).

[0032] b) Preparation of Compound I-1: Weigh Compound 3 (177.2 mg, 1 mmol) and dissolve it in dimethyl sulfoxide, add Compound 2-1 (350 mg, 1.5 mmol), stir at room temperature for 0.5 hours, heat to 80°C, keep at 80°C for 24 hours, and precipitate a pale yellow-green solid. Filter, wash the filter cake with ethyl acetate three times, dialyze, and freeze-dry to obtain Compound I-1 (293.3 mg, yield 80.5%).

[0033] Compound I-1 was subjected to FTIR characterization, and the results were as follows:

[0034] 3311cm -1 (OH),2926cm -1 ,2886cm -1 (saturated CH) 1619cm -1 (Benzene ring C=C), 1520cm -1 (Benzene ring C=C), 1383cm -1 ,1252cm -1 (COC on sugar ring), 1152cm -1 (CN),1076cm -1 (Primary alcohol CO), 888cm -1 (=CH out-of-plane bending vibration, benzene ring monosubstituted), 768cm -1 (=CH out-of-plane bending vibration, benzene ring monosubstituted).

[0035] Example 2

[0036] The synthesis route of compound I-2 is as follows:

[0037]

[0038] The synthesis steps are as follows:

[0039] a) Preparation of compound 2-2: Compound 1-2 (465.5 mg, 1 mmol) was dissolved in dry acetonitrile, 0.6 mL of carbon disulfide was added, and the mixture was stirred at 60°C for 24 hours, the solvent was evaporated under reduced pressure, and ethyl acetate / petroleum ether (volume ratio of 1:4) was added for recrystallization. The mixture was filtered, and the mother liquor was evaporated under reduced pressure to obtain a light yellow solid compound 2-2 (210.5 mg, yield of 85.1%).

[0040] b) Preparation of compound I-2: Weigh compound 3 (177.2 mg, 1 mmol) and dissolve it in dimethyl sulfoxide, add compound 2-2 (247.3 mg, 1.0 mmol), stir at room temperature for 0.5 hours, heat to 80°C, keep at 80°C for 72 hours, and precipitate a light yellow solid. Filter, wash the filter cake with ethyl acetate three times, dialyze, and freeze-dry to obtain compound I-2 (311.4 mg, yield 82.3%).

[0041] Compound I-2 was characterized, and the results were as follows:

[0042] 3314cm -1 (OH),2936cm -1 ,2878cm -1 (saturated CH) 1623cm -1 (Benzene ring C=C) 1516cm -1 (Benzene ring C=C), 1381cm -1 (COC on sugar ring), 1249cm -1 (CN),1073cm -1 (Primary alcohol CO), 893cm -1 (=CH out-of-plane bending vibration, para-substitution of benzene ring).

[0043] Example 3

[0044] The synthesis route of compound I-3 is as follows:

[0045]

[0046] The synthesis steps are as follows:

[0047] a) Preparation of compound 2-3: Compound 1-3 (481.5 mg, 1 mmol) was dissolved in dry acetonitrile, 0.6 mL of carbon disulfide was added, and the mixture was stirred at 60°C for 24 hours, the solvent was evaporated under reduced pressure, and ethyl acetate / petroleum ether (volume ratio of 1:4) was added for recrystallization. The mixture was filtered, and the mother liquor was evaporated under reduced pressure to obtain a light yellow solid compound 2-3 (232.5 mg, yield of 87.1%).

[0048] b) Preparation of compound I-3: Weigh compound 3 (177.2 mg, 1 mmol) and dissolve it in dimethyl sulfoxide, add compound 2-3 (247.3 mg, 1.0 mmol), stir at room temperature for 0.5 hours, heat to 80°C, keep at 80°C for 72 hours, and precipitate a light yellow solid. Filter, wash the filter cake with ethyl acetate three times, dialyze, and freeze-dry to obtain compound I-3 (343.5 mg, yield 87.1%).

[0049] Compound I-3 was characterized, and the results were as follows:

[0050] 3391cm -1 (OH),2940cm -1 ,2889cm -1 (saturated CH) 1620cm -1 (Benzene ring C=C) 1516cm -1 (Benzene ring C=C), 1417cm -1 (Benzene ring C=C), 1374cm -1 (COC on sugar ring), 1321cm -1 (CN),1155cm -1 (primary alcohol CO), 1032cm -1 (COC), 896cm -1 (=CH out-of-plane bending vibration, para-substitution of benzene ring).

[0051] Example 4

[0052] The synthesis route of compound I-4 is as follows:

[0053]

[0054] The synthesis steps are as follows:

[0055] a) Preparation of compound 2-4: Compound 1-4 (469.5 mg, 1 mmol) was dissolved in dry acetonitrile, 0.6 mL of carbon disulfide was added, and the mixture was stirred at 60°C for 24 hours, and the solvent was evaporated under reduced pressure, and ethyl acetate / petroleum ether (volume ratio of 1:4) was added for recrystallization. The mixture was filtered, and the mother liquor was evaporated under reduced pressure to obtain a light yellow solid compound 2-4 (198.5 mg, yield of 79.1%).

[0056] b) Preparation of compound I-4: Weigh compound 3 (177.2 mg, 1 mmol) and dissolve it in dimethyl sulfoxide, add compound 2-4 (251.3 mg, 1.0 mmol), stir at room temperature for 0.5 hours, heat to 80°C, keep at 80°C for 72 hours, and precipitate a light yellow solid. Filter, wash the filter cake with ethyl acetate three times, dialyze, and freeze-dry to obtain compound I-4 (276.1 mg, yield 72.2%).

[0057] Compound I-4 was characterized, and the results were as follows:

[0058] 3295cm -1 (OH),2881cm -1 ,2822cm -1 (saturated CH) 1650cm -1 (Benzene ring C=C) 1509cm -1(Benzene ring C=C), 1381cm -1 (COC on sugar ring), 1322cm -1 (CN),1241cm -1 ,1156cm -1 (primary alcohol CO), 1065cm -1 (COC), 896cm -1 (=CH out-of-plane bending vibration, para-substitution of benzene ring).

[0059] Example 5

[0060] The synthesis route of compound I-5 is as follows:

[0061]

[0062] The synthesis steps are as follows:

[0063] a) Preparation of compound 2-5: Compound 1-5 (486 mg, 1 mmol) was dissolved in dry acetonitrile, 0.6 mL of carbon disulfide was added, and the mixture was stirred at 60°C for 24 hours, the solvent was evaporated under reduced pressure, and ethyl acetate / petroleum ether (volume ratio of 1:4) was added for recrystallization. The mixture was filtered, and the mother liquor was evaporated under reduced pressure to obtain a light yellow solid compound 2-5 (201.9 mg, yield of 75.4%).

[0064] b) Preparation of compound I-5: Weigh compound 3 (177.2 mg, 1 mmol) and dissolve it in dimethyl sulfoxide, add compound 2-5 (267.7 mg, 1.0 mmol), stir at room temperature for 0.5 hours, heat to 80°C, keep at 80°C for 72 hours, and precipitate a light yellow solid. Filter, wash the filter cake with ethyl acetate three times, dialyze, and freeze-dry to obtain compound I-5 (272 mg, yield 68.2%).

[0065] Compound I-5 was characterized, and the results were as follows:

[0066] 3273cm-1(OH), 2885cm-1, 2826cm-1(saturated CH) 1619cm-1(benzene ring C=C), 1513cm-1(benzene ring C=C), 1377cm-1(COC on sugar ring), 1249cm-1(CN), 1152cm-1, 1069cm-1(COC), 901cm-1(=CH out-of-plane bending vibration, para-substitution on benzene ring).

[0067] Example 6

[0068] The synthesis route of compound I-6 is as follows:

[0069]

[0070] The synthesis steps are as follows:

[0071] a) Preparation of compound 2-6: Compound 1-6 (530.4 mg, 1 mmol) was dissolved in dry acetonitrile, 0.6 mL of carbon disulfide was added, and the mixture was stirred at 60°C for 24 hours, and the solvent was evaporated under reduced pressure, and ethyl acetate / petroleum ether (volume ratio of 1:4) was added for recrystallization. The mixture was filtered, and the mother liquor was evaporated under reduced pressure to obtain a light yellow solid compound 2-6 (197.7 mg, yield of 72.7%).

[0072] b) Preparation of compound I-6: Weigh compound 3 (177.2 mg, 1 mmol) and dissolve it in dimethyl sulfoxide, add compound 2-6 (312.2 mg, 1.0 mmol), stir at room temperature for 0.5 hours, heat to 80°C, keep at 80°C for 72 hours, and precipitate a light yellow solid. Filter, wash the filter cake with ethyl acetate three times, dialyze, and freeze-dry to obtain compound I-6 (291.2 mg, yield 65.7%).

[0073] Compound I-5 was characterized, and the results were as follows:

[0074] 3400cm -1 (OH),2951cm -1 ,2878cm -1 (saturated CH) 1623cm -1 (Benzene ring C=C), 1513 cm -1 (Benzene ring C=C), 1373cm -1 (COC on sugar ring), 1245cm -1 (CN),1156cm -1 ,1073cm -1 (COC),896cm -1 (=CH out-of-plane bending vibration, para-substitution of benzene ring).

[0075] Example 7 Antibacterial Activity Determination

[0076] 1) Preparation of chitosanase crude solution

[0077] Weigh 30g of powdered enzyme sample (chitosanase content 68%), add 70mL of distilled water to dissolve, stir and let stand, soak for 3h. Centrifuge again, set the speed to 4000r / min, centrifuge for 20min, and obtain a yellow supernatant. Encapsulate the enzyme-containing supernatant and store it in a refrigerator at 4°C.

[0078] 2) Enzymatic hydrolysis of compounds I-1 to I-6

[0079] Weigh the solid sample compounds I-1 to I-6 prepared in Examples 1-6 using an analytical balance, and dissolve them in 1 mL of HAc-NaAc buffer solution at pH 5.8. Prepare the corresponding 20 mmol / L concentration samples I-1 to I-6, add 2 mL of activated chitosanase crude solution, and then hydrolyze at 50°C for about 100 minutes, then heat to 100°C to inactivate the enzymes in the degradation samples I-1 to I-6. Then select the sample for centrifugation (speed of 4000 r / min, time of 5-10 min). After centrifugation, the supernatant was taken and the degraded sample solutions I-1 to I-6 were added to the LB medium containing Escherichia coli; 1 mL of HAc-NaAc buffer solution with a pH of 5.8 was added to the LB medium containing Escherichia coli, which was set as a blank sample. The blank sample and sample solutions I-1 to I-6 were cultured in a constant temperature incubator for 24 hours (the culture temperature was 37°C), the diameter of the colonies in each sample was measured, and the inhibition rate was calculated according to the following formula. The results are shown in Table 1.

[0080] Antibacterial rate (%) = [(sample outer diameter - sample inner diameter) - (blank sample outer diameter - blank sample inner diameter)] / (sample outer diameter - sample inner diameter) = [(sample outer diameter - blank sample outer diameter)] / (sample outer diameter - sample inner diameter)] × 100%.

[0081] Table 1 Antibacterial activity of compounds I-1 to I-6 after enzymatic hydrolysis

[0082]

[0083] It can be seen from the above antibacterial activity that the para position of Ph with an electron-donating substituent such as CH3 (compound I-2), CH3O (compound I-3), F (compound I-4), Cl (compound I-5), and Br (compound I-6) is beneficial to improving the antibacterial activity.

[0084] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A chitosan derivative modified with 2-imidazolidinone, characterized in that: Its structural formula is: Among them, Ar= Ph, 4-CH3O-Ph, 4-CH3-Ph,4-F-Ph, 4-Cl-Ph, 4-Br-Ph, n=11-500.

2. The method for preparing a chitosan derivative modified with 2-imidazolidinone according to claim 1, characterized in that: Its synthesis route is as follows: Wherein, Ar = Ph, 4-CH3O-Ph, 4-CH3-Ph,4-F-Ph, 4-Cl-Ph, 4-Br-Ph, n = 11-500; The synthesis steps are: a) dissolving compound 1 in a first solvent, adding carbon disulfide, heating to react for 24-36 hours, cooling to room temperature and concentrating under reduced pressure, recrystallizing to precipitate a solid, filtering, and concentrating the mother liquor under reduced pressure to evaporate the solvent to obtain compound 2; b) Compound 3 is dissolved in a second solvent, and compound 2 is added at room temperature, and the mixture is heated and stirred for reaction for 24-72 hours. The mixture is cooled to room temperature and concentrated under reduced pressure, filtered, dried, dialyzed, and then freeze-dried to obtain compound I.

3. The method for preparing a chitosan derivative modified with 2-imidazolidinone according to claim 2, characterized in that: In the step a), the molar ratio of compound 1 to carbon disulfide is 1:10-15.

4. The method for preparing a chitosan derivative modified with 2-imidazolidinone according to claim 2, characterized in that: In the step a), the first solvent is dichloromethane, acetonitrile or a mixture of the two.

5. The method for preparing a chitosan derivative modified with 2-imidazolidinone according to claim 2, characterized in that: In the step a), the reaction temperature is 60° C. and the reaction time is 24 h.

6. The method for preparing a chitosan derivative modified with 2-imidazolidinone according to claim 2, characterized in that: In the step b), the molar ratio of compound 2 to compound 3 is 1:1-1.

5.

7. The method for preparing a chitosan derivative modified with 2-imidazolidinone according to claim 2, characterized in that: In the step b), the second solvent is acetonitrile, N, N-dimethylformamide or a mixture of the two.

8. The method for preparing a chitosan derivative modified with 2-imidazolidinone according to claim 2, characterized in that: In the step b), the reaction temperature is 80° C. and the reaction time is 72 h.

9. Use of a chitosan derivative modified with 2-imidazolidinone according to claim 1 in the preparation of antibacterial materials.

10. The use of a chitosan derivative modified with 2-imidazolidinone according to claim 9 in the preparation of antibacterial materials, characterized in that: The antibacterial rate of the antibacterial material on Escherichia coli is 80-90%.

Images