Novel furfuryl Schiff base as well as synthesis method and application thereof

Abstract

The invention belongs to the technical field of fine organic chemical synthesis, and particularly relates to a novel furil Schiff base and a synthesis method and application thereof, and the synthesis method comprises the following steps: step 1, reacting furil with hydrazine hydrate to obtain furil monohydrazone; 2, in the presence of a solvent, the furfuryl monohydrazone in the step 1 is used as a raw material to be condensed with an aldehyde agent to obtain novel furfuryl Schiff base; wherein the aldehyde agent is selected from one of furfural, m-chlorobenzaldehyde, benzaldehyde, p-fluorobenzaldehyde, p-chlorobenzaldehyde, p-methyl benzaldehyde, p-dimethylaminobenzaldehyde and p-nitrobenzaldehyde; the synthesis method of the novel furfuryl Schiff base disclosed by the invention does not exist in the prior art at present. The synthesis mechanism is simple, no complex reaction mechanism is contained, the reaction device is simple, the conditions are mild, the extraction method is easy and convenient to operate, and the product is easy to separate and high in purity.

Description

Technical Field

[0001] The invention belongs to the technical field of fine organic chemical synthesis, and specifically relates to a novel furilyl Schiff base and a synthesis method and application thereof. Background Art

[0002] Schiff bases, also known as imines, have a (-C=N-) functional group in their structure. They are easy to form a ring and coordinate, and are a very important class of nitrogen-containing organic compounds. Schiff bases are usually formed by the condensation of amines and carbonyl groups, and are easy to synthesize and have few by-products.

[0003] The application of Schiff bases involves the medical field, especially in drug research. The application of Schiff bases in drug research not only shows their potential as drugs for the treatment of cancer, malaria and tuberculosis, but also shows antibacterial, antifungal and antiviral activities. For example: the 5-bromosalicylaldehyde-2-chloro-6-hydrazinepyridine Schiff base nickel complex and synthesis method of the anticancer drug 5-bromosalicylaldehyde-2-chloro-6-hydrazinepyridine Schiff base synthesized in the prior art (publication number CN107840821A, patent name: an anticancer drug 5-bromosalicylaldehyde-2-chloro-6-hydrazinepyridine Schiff base nickel complex Ni (bchp) 2 is obtained by combining 5-bromosalicylaldehyde-2-chloro-6-hydrazinepyridine Schiff base with Ni.

[0004] Schiff base coordinated with some transition metals can be used to prepare fluorescent probes and many other fields. For example, the existing technology (publication number CN106966924A, patent name: Preparation and application of zinc ion fluorescent probe based on Schiff base) coordinates Schiff base with zinc ions to obtain a complex with good selectivity, sensitivity and low detection limit for zinc ions, which can be used to determine the content of zinc ions in water.

[0005] The imine bond contained in the Schiff base is a dynamically reversible chemical bond that can be used to synthesize repairable materials and exhibits good performance. For example: the prior art (publication number CN116655505A, patent name: a cystamine salicylaldehyde Schiff base, preparation method, polyurethane) uses a chain extender-cystamine Schiff base to prepare a polyurethane damping material that exhibits excellent damping and self-repairing properties. It can be applied to biomedicine, bionic materials, electrolytic cell materials, hydrogen bonded thermal conductive plastic elastomers, self-repairing polymer glass, etc. Summary of the invention

[0006] The purpose of the present invention is to provide a method for synthesizing a novel furilyl Schiff base to obtain a series of different novel furilyl Schiff bases.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for synthesizing a novel furilyl Schiff base comprises the following steps: Step 1: react furil with hydrazine hydrate to obtain furil monohydrazone (Ⅰ) ; Step 2: In the presence of a solvent, the furilyl monohydrazone (I) in step 1 is used as a raw material to carry out condensation with an aldehyde agent to obtain a furilyl novel Schiff base; Wherein, the aldehyde agent is selected from one of furfural, m-chlorobenzaldehyde, benzaldehyde, p-fluorobenzaldehyde, p-chlorobenzaldehyde, p-tolualdehyde, p-dimethylaminobenzaldehyde and p-nitrobenzaldehyde; ; ; , R=-H, -F, Cl, -CH3, -N(CH3)2, -NO2.

[0008] In a preferred example, in step 1, the molar ratio of furil to hydrazine hydrate is 1:1-2.5.

[0009] In a preferred example, in step 2, the solvent is selected from ethanol, acetonitrile, methanol, isopropanol, 1,4-dioxane, and water.

[0010] In a preferred example, in step 2, the molar ratio of furilyl monohydrazone to the aldehyde agent is 1:1.

[0011] In a preferred example, in step 2, the reaction conditions of the condensation are: reflux at 60°C to 120°C for 4h to 6h. After the reaction is completed, the solution is cooled, filtered after the solute is precipitated, the solid phase is washed, and then recrystallized to obtain the product.

[0012] Based on a general inventive concept, another object of the present invention is to provide a novel furilyl Schiff base synthesized by the above-mentioned synthesis method, wherein the structural formulas (II) to (IX) are respectively as follows: , , , , , , , .

[0013] Up to now, the prior art has not disclosed a method for synthesizing several novel furilyl Schiff bases shown in the present invention; first, furilyl is reacted with hydrazine hydrate to obtain furilyl monohydrazone, and then furilyl monohydrazone is used as a raw material to condense with 8 different aldehydes to obtain 8 different novel furilyl Schiff bases.

[0014] Based on a general inventive concept, another object of the present invention is to provide the use of the above-mentioned novel furyl Schiff base in inhibiting diseases (rice sheath blight pathogen, tobacco black shank pathogen and / or watermelon wilt pathogen) on field crops.

[0015] The advantages of the method of the present invention are: simple synthesis mechanism, no complex reaction mechanism (all reactions are reactions between amino groups and carbonyl groups C=O of aldehydes and ketones), simple reaction apparatus, relatively mild conditions, simple extraction method, easy separation of products and high purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The infrared spectrum of furilyl monohydrazone (I) prepared by the present invention; Figure 2 Infrared spectra of the novel furilyl Schiff bases (II) to (IX) prepared by the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in conjunction with specific embodiments, but the present invention is not limited to these embodiments. It should be noted that, under the premise of no conflict, the embodiments described below or the technical features can be arbitrarily combined to form new embodiments. In the present invention, unless otherwise specified, the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, if not otherwise specified, are conventional methods in the art.

[0018] As used herein, the terms "comprises," "including," "contains," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0019] When the amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range limited by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether this range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc. When a numerical range is described in this article, unless otherwise stated, this range is intended to include its end values ​​and all integers and fractions within this range.

[0020] Example 1

[0021] Preliminary study on the synthesis, extraction and separation methods and process conditions of the raw material furanil monohydrazone: (1) Add 0.5 g of furil into a 25 mL round-bottom flask, add 0.1933 g of hydrazine hydrate (content 80%) in a molar ratio of 1:1.5, add 4 mL of ethanol as a solvent into the round-bottom flask, and dropwise add an appropriate amount of glacial acetic acid, and reflux at 100 ° C for 1 hour. After the reaction is completed, add water to precipitate the solute, centrifuge, and pour off the supernatant; separate the red viscous material in the centrifuge tube with a chromatography column (eluent PE: EA = 1: 1), and detect by TLC while eluting, and collect the target product furil monohydrazone (Ⅰ), with a yield of 26.07%.

[0022] (2) Add 0.5 g of furil into a 25 mL round-bottom flask, add 0.2577 g of hydrazine hydrate (content 80%) in a molar ratio of 1:2, add 4 mL of ethanol as a solvent into the round-bottom flask, and dropwise add an appropriate amount of glacial acetic acid, and reflux at 100 ° C for 1 hour. After the reaction is completed, add water to precipitate the solute, centrifuge, and pour off the supernatant; separate the red viscous material in the centrifuge tube with a chromatography column (eluent PE: EA = 1: 1), and detect by TLC while eluting, and collect the target product furil monohydrazone (Ⅰ), with a yield of 31.42%.

[0023] (3) Add 0.5 g of furil into a 25 mL round-bottom flask, add 0.3222 g of hydrazine hydrate (content 80%) at a molar ratio of 1:2.5, add 4 mL of ethanol as a solvent into the round-bottom flask, and dropwise add an appropriate amount of glacial acetic acid, and reflux at 100 ° C for 1 hour. After the reaction is completed, add water to precipitate the solute, centrifuge, and pour off the supernatant; separate the red viscous material in the centrifuge tube with a chromatography column (eluent PE: EA = 1: 1), and detect by TLC while eluting, and collect the target product: furil monohydrazone (Ⅰ), with a yield of 27.84%.

[0024] In summary, the yield is highest when the ratio of furil to hydrazine hydrate is 1:2.

[0025] 1 H-NMR (400 MHz, DMSO-d6): δ 8.89 (s, 2H), 7.95 (d, J = 1.7hz, 1H), 7.81 (d, J = 1.7hz, 1H), 7.36 (d, J = 3.5hz, 1H), 6.94 (d, J = 3.4hz, 1H), 6.66 (ddd, J = 9.2, 3.5,1.8hz, 2H). Example 2

[0026] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) and 0.0942 g of furfural were added in a molar ratio of 1:1. 2 mL of ethanol was used as a solvent and refluxed at 90 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered and washed with a small amount of ethanol. The solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (II), with a yield of 16.48%.

[0027] 1 H-NMR (400 MHz, DMSO-d6): δ 8.51 (s, 1H), 8.10 (d, J = 1.6hz, 1H), 8.00 (d, J = 1.7hz, 1H), 7.89 (d, J = 1.7hz, 1H), 7.39 (d, J = 3.7hz, 1H), 7.08 (d, J = 3.5hz, 1H), 7.00 (d, J = 3.6hz, 1H), 6.77 (dd, J = 3.7, 1.7hz, 1H), 6.72 (dd, J = 3.6, 1.8hz, 1H), 6.66 (dd, J = 3.5, 1.8hz, 1H). Example 3

[0028] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1378 g of m-chlorobenzaldehyde was added in a molar ratio of 1:1. 2 mL of ethanol was used as a solvent, and the mixture was refluxed at 90 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (III), with a yield of 38.86%.

[0029] 1 H NMR (400 MHz, DMSO-d6): δ 8.70 (s, 1H), 8.12 (d, J = 1.6hz, 1H), 8.05 (d, J = 1.7hz, 1H), 7.63 (s, 1H), 7.59 – 7.53 (m, 2H), 7.50 – 7.43 (m, 2H), 7.08 (d, J = 3.6hz, 1H), 6.80 (dd, J = 3.7, 1.7hz, 1H), 6.76 (dd, J = 3.6, 1.7hz, 1H). Example 4

[0030] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1041 g of benzaldehyde was added in a molar ratio of 1:1. 2 mL of ethanol was used as a solvent, and the mixture was refluxed at 90 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (IV), with a yield of 28.01%.

[0031] 1 H-NMR (400 MHz, DMSO-d6): δ 8.70 (s, 1H), 8.11 (d, J = 1.6hz, 1H), 8.03 (d, J = 1.7hz, 1H), 7.62 (d, J = 8.5hz, 2H), 7.48 (d, J = 7.1hz, 1H), 7.44 (s, 1H), 7.44 – 7.39 (m, 2H), 7.05 (d, J = 3.5hz, 1H), 6.78 (dd, J = 3.7, 1.7hz, 1H), 6.75 (dd, J= 3.6, 1.8hz, 1H). Example 5

[0032] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1217 g of p-fluorobenzaldehyde was added in a molar ratio of 1:1. 2 mL of ethanol was used as a solvent, and the mixture was refluxed at 90 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (V), with a yield of 18.81%.

[0033] 1 H NMR (400 MHz, DMSO-d6): δ 8.70 (s, 1H), 8.10 (d, J = 1.3hz, 1H), 8.02 (d, J = 1.7hz, 1H), 7.67 (dd, J = 8.7, 5.7hz, 2H), 7.43 (d, J = 3.3hz, 1H), 7.29 (t, J = 8.9hz, 2H), 7.04 (d, J = 3.6hz, 1H), 6.78 (dd, J = 3.7, 1.7hz, 1H), 6.74 (dd, J =3.6, 1.8hz, 1H). Example 6

[0034] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1378 g of p-chlorobenzaldehyde was added in a molar ratio of 1:1. 2 mL of ethanol was used as a solvent, and the mixture was refluxed at 90 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (VI), with a yield of 31.96%.

[0035] 1 H NMR (400 MHz, DMSO-d6): δ 8.70 (s, 1H), 8.10 (d, J = 1.4hz, 1H), 8.03 (d, J = 1.7hz, 1H), 7.62 (d, J = 8.6hz, 2H), 7.51 (d, J = 8.6hz, 2H), 7.43 (dd, J = 3.7, 0.7hz, 1H), 7.05 (d, J = 3.9hz, 1H), 6.78 (dd, J = 3.7, 1.7hz, 1H), 6.74 (dd, J =3.6, 1.8hz, 1H). Example 7

[0036] In a 25 mL round-bottom flask, add 0.2 g of furil monohydrazone (I), add 0.1178 g of p-methylbenzaldehyde in a molar ratio of 1:1, use 2 mL of ethanol as solvent, reflux at 90 ° C for 5 h, and after the reaction, cool the solution (if no precipitation can be obtained after long-term stirring, rub the inner wall of the flask with a glass rod). After the solute precipitates, filter it by suction, wash it with a small amount of ethanol, and recrystallize the obtained solid with methanol to obtain the product (VII) with a yield of 20.90%.

[0037] 1 H NMR (400 MHz, DMSO-d6): δ 8.64 (s, 1H), 8.09 (d, J = 1.7hz, 1H), 8.01 (d, J = 1.8hz, 1H), 7.50 (d, J = 8.1hz, 2H), 7.42 (d, J = 3.7hz, 1H), 7.24 (d, J = 7.9hz, 2H), 7.02 (d, J = 3.5hz, 1H), 6.77 (dd, J = 3.7, 1.7hz, 1H), 6.73 (dd, J = 3.6, 1.8hz, 1H), 2.32 (s, 3H). Example 8

[0038] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1463 g of p-dimethylaminobenzaldehyde was added in a molar ratio of 1:1. 2 mL of ethanol was used as a solvent, and the mixture was refluxed at 90 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (VIII), with a yield of 27.59%.

[0039] 1 H NMR (400 MHz, DMSO-d6): δ 8.48 (s, 1H), 8.07 (d, J = 1.7hz, 1H), 7.95 (d, J = 1.7hz, 1H), 7.41 (d, J = 9.0hz, 2H), 7.36 (d, J = 4.4hz, 1H), 6.92 (d, J = 3.9hz, 1H), 6.75 (dd, J = 3.7, 1.7hz, 1H), 6.70 (d, J = 1.5hz, 1H), 6.70 – 6.66 (m, 2H), 2.97 (s, 6H). Example 9

[0040] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1480 g of p-nitrobenzaldehyde was added in a molar ratio of 1:1. 2 mL of ethanol was used as a solvent and refluxed at 90 ° C for 5 h. After the reaction was completed, the solution was cooled and filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with ethyl acetate to obtain the product: furilyl novel Schiff base (IX), with a yield of 39.34%.

[0041] 1 H NMR (400 MHz, DMSO-d6): δ 8.85 (s, 1H) , 8.28 (d, J = 8.8 Hz, 2H) , 8.13 (d, J = 1.6 Hz, 1H), 8.08 (d, J = 1.7 Hz, 1H), 7.86 (d, J = 8.9 Hz, 2H) ,7.47 (d, J = 3.7 Hz, 1H), 7.13 (d, J = 3.6 Hz, 1H), 6.80 (dd, J = 3.7, 1.8 Hz, 1H), 6.78 (dd, J= 3.6, 1.8 Hz, 1H). Example 10

[0042] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1041 g of benzaldehyde was added in a molar ratio of 1:1. 2 mL of acetonitrile was used as a solvent, and refluxed at 90 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (IV), with a yield of 28.09%.

[0043] Embodiment 11

[0044] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1178 g of p-methylbenzaldehyde was added in a molar ratio of 1:1. 2 mL of methanol was used as a solvent, and the mixture was refluxed at 90 °C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (VII), with a yield of 21.40%.

[0045] Example 12

[0046] 0.2 g of furilyl monohydrazone (I) was added to a 25 mL round-bottom flask, and 0.1378 g of p-chlorobenzaldehyde was added at a molar ratio of 1:1. 2 mL of isopropanol was used as a solvent, and the mixture was refluxed at 120 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if the solute could not precipitate after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (VI), with a yield of 78.93%. Example 13

[0047] 0.2 g of furilyl monohydrazone (I) was added to a 25 mL round-bottom flask, and 0.1378 g of p-chlorobenzaldehyde was added at a molar ratio of 1:1. 2 mL of methanol was used as a solvent, and refluxed at 120 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (VI), with a yield of 21.74%. Embodiment 14

[0048] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1041 g of benzaldehyde was added in a molar ratio of 1:1. 2 mL of methanol was used as a solvent, and the mixture was refluxed at 60 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (IV), with a yield of 93.25%.

[0049] Embodiment 15

[0050] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1178 g of p-methylbenzaldehyde was added in a molar ratio of 1:1. 2 mL of 1,4-dioxane was used as a solvent. The reaction was refluxed at 80 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after stirring for a long time, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered and washed with a small amount of ethanol. The solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (VII), with a yield of 14.27%.

[0051] Example 16

[0052] In a 25 mL round-bottom flask, 0.2 g of furilyl monohydrazone (I) was added, and 0.1041 g of benzaldehyde was added in a molar ratio of 1:1. 2 mL of water was used as a solvent, and the mixture was refluxed at 75 ° C for 5 h. After the reaction was completed, the solution was cooled. After the solution was cooled, it was stirred to precipitate the solute (if it could not be precipitated after long-term stirring, a glass rod was used to rub the inner wall of the flask). After the solute precipitated, it was filtered, washed with a small amount of ethanol, and the solid obtained by filtration was recrystallized with methanol to obtain the product: furilyl novel Schiff base (IV), with a yield of 29.36%.

[0053] Embodiment 17

[0054] In a 25 ml round-bottom flask, add 0.2 g of furilyl monohydrazone (I), add 0.1041 g of benzaldehyde in a molar ratio of 1:1, use 2 ml of methanol as solvent, reflux at 70 ° C for 5 hours, and cool the solution after the reaction is completed. After the solution is cooled, stir to precipitate the solute (if it cannot be precipitated after long-term stirring, use a glass rod to rub the inner wall of the flask). After the solute is precipitated, filter it, wash it with a small amount of ethanol, and use methanol to recrystallize the solid obtained by filtration to obtain the product: furilyl novel Schiff base (IV), with a yield of 57.79%.

[0055] Embodiment 18

[0056] In a 25 ml round-bottom flask, add 0.2 g of furilyl monohydrazone (I), add 0.1041 g of benzaldehyde in a molar ratio of 1:1, use 2 ml of isopropanol as solvent, reflux at 70 ° C for 5 hours, and cool the solution after the reaction is completed. After the solution is cooled, stir to precipitate the solute (if it cannot be precipitated after long-term stirring, use a glass rod to rub the inner wall of the flask). After the solute is precipitated, filter it, wash it with a small amount of ethanol, and use methanol to recrystallize the solid obtained by filtration to obtain the product: furilyl novel Schiff base (IV), with a yield of 67.74%.

[0057] Embodiment 19

[0058] In a 25 ml round-bottom flask, add 0.2 g of furilyl monohydrazone (I), add 0.1378 g of p-chlorobenzaldehyde in a molar ratio of 1:1, use 2 ml of methanol as solvent, reflux at 70 ° C for 5 hours, and cool the solution after the reaction is completed. After the solution is cooled, stir to precipitate the solute (if it cannot be precipitated after long-term stirring, use a glass rod to rub the inner wall of the flask). After the solute is precipitated, filter it, wash it with a small amount of ethanol, and use methanol to recrystallize the solid obtained by filtration to obtain the product: furilyl novel Schiff base (VI), with a yield of 58.04%.

[0059] Embodiment 20

[0060] In a 25 ml round-bottom flask, add 0.2 g of furilyl monohydrazone (I), add 0.1178 g of p-methylbenzaldehyde in a molar ratio of 1:1, use 2 ml of methanol as solvent, reflux at 70 ° C for 5 hours, and cool the solution after the reaction is completed. After the solution is cooled, stir to precipitate the solute (if it cannot be precipitated after long-term stirring, use a glass rod to rub the inner wall of the flask). After the solute is precipitated, filter it, wash it with a small amount of ethanol, and use methanol to recrystallize the solid obtained by filtration to obtain the product: furilyl novel Schiff base (VII), with a yield of 53.59%.

[0061] Embodiment 21

[0062] In a 25 ml round-bottom flask, add 0.2 g of furilyl monohydrazone (Ⅰ), add 0.1178 g of p-nitrobenzaldehyde in a molar ratio of 1:1, use 2 ml of methanol as solvent, reflux at 70 ° C for 5 hours, and cool the solution after the reaction is completed. After the solution is cooled, stir to precipitate the solute (if it cannot be precipitated after long-term stirring, use a glass rod to rub the inner wall of the flask). After the solute is precipitated, filter it, wash it with a small amount of ethanol, and use ethyl acetate to recrystallize the solid obtained by filtration to obtain the product: furilyl novel Schiff base (IX), with a yield of 72.24%.

[0063] Test Example 1 The novel furilyl Schiff bases (II) to (IX) prepared in the examples of the present invention were tested against diseases (rice sheath blight, tobacco black shank pathogen, watermelon wilt pathogen) on field crops. The results of antibacterial activity are shown in Table 1 below.

[0064] Table 1 Antibacterial activity of novel furil-based Schiff bases (II) to (IX)

[0065] The antibacterial test showed that the new furyl Schiff bases (II) to (IX) had good inhibitory effects on rice sheath blight; the new furyl Schiff bases (II) to (VII) had good inhibitory effects on tobacco black shank, while the new furyl Schiff bases (VIII) and (IX) had poor inhibitory effects on tobacco black shank; the new furyl Schiff bases (II) to (VI) had good inhibitory effects on watermelon wilt, while compounds (VII) and (IX) had poor inhibitory effects on watermelon wilt, and compound VIII had almost no inhibitory effect on watermelon wilt.

[0066] The above embodiments are merely preferred implementations of the present invention. Any simple modification, amendment and substitution of the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A method for synthesizing a novel furilyl Schiff base, characterized in that: The following steps are involved: Step 1: react furil with hydrazine hydrate to obtain furil monohydrazone (Ⅰ) ； Step 2: In the presence of a solvent, the furilyl monohydrazone (I) in step 1 is used as a raw material to carry out condensation with an aldehyde agent to obtain a furilyl novel Schiff base; Wherein, the aldehyde agent is selected from one of furfural, m-chlorobenzaldehyde, benzaldehyde, p-fluorobenzaldehyde, p-chlorobenzaldehyde, p-tolualdehyde, p-dimethylaminobenzaldehyde and p-nitrobenzaldehyde; ； ； ， R=-H, -F, Cl, -CH3, -N(CH3)2, -NO2.

2. The method for synthesizing a novel furilyl Schiff base according to claim 1, characterized in that: In step 1, the molar ratio of furil to hydrazine hydrate is 1:1-2.

5.

3. The method for synthesizing a novel furilyl Schiff base according to claim 1, characterized in that: In step 2, the solvent is selected from ethanol, acetonitrile, methanol, isopropanol, 1,4-dioxane, and water.

4. The method for synthesizing a novel furilyl Schiff base according to claim 1, characterized in that: In step 2, the molar ratio of furil monohydrazone to the aldehyde agent is 1:

1.

5. The method for synthesizing a novel furilyl Schiff base according to claim 1, characterized in that: In step 2, the reaction conditions of the condensation are: reflux at 60°C to 120°C for 4h to 6h. After the reaction is completed, the solution is cooled, filtered after the solute is precipitated, the solid phase is washed, and then recrystallized to obtain the product.

6. The novel furyl Schiff base synthesized by the synthesis method according to any one of claims 1 to 5, characterized in that: The structural formulas (II) to (IX) of the novel furilyl Schiff base are shown below: ， ， ， ， ， ， ， 。 7. Use of the novel furilyl Schiff base according to claim 6 in inhibiting diseases on field crops, characterized in that: The diseases are rice sheath blight pathogen, tobacco black shank pathogen and / or watermelon wilt pathogen.

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