1-cyano-3-bromine-6-imine-5-cyclohexenecarboxaldehyde derivative with antibacterial activity as well as synthesis method and application of 1-cyano-3-bromine-6-imine-5-cyclohexenecarboxaldehyde derivative

Abstract

The invention discloses a synthesis method of a 1-cyano-3-bromine-6-imine-5-cyclohexenecarboxaldehyde derivative with antibacterial activity, which comprises the following steps: by taking 2-(2-bromine-1-phenyl) malononitrile (1) and alpha, beta-unsaturated aldehyde as raw materials, reacting for 24 hours in an organic solvent under the catalysis of a catalyst, filtering, washing and drying to obtain the 1-cyano-3-bromine-6-imine-5-cyclohexenecarboxaldehyde derivative with antibacterial activity, thereby obtaining the 1-cyano-3-bromine-6-imine-5-cyclohexenecarboxaldehyde derivative with antibacterial activity. And carrying out allylic mimic addition-cyclization reaction to obtain the 1-cyano-3-bromine-6-imine-5-cyclohexenecarboxaldehyde derivative with the antibacterial activity. The synthesis method has the advantages of simple and easily available raw materials, low price, simple operation, high yield and convenient post-treatment, and is suitable for industrial production. The invention also discloses an application of the 1-cyano-3-bromine-6-imine-5-cyclohexenecarboxaldehyde derivative as an antibacterial agent, and a preparation method of the 1-cyano-3-bromine-6-imine-5-cyclohexenecarboxaldehyde derivative

Description

Technical Field

[0001] The present invention belongs to the field of synthetic medicine and chemical industry, and mainly relates to a heterocyclic compound with antibacterial activity, namely, a 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative, and a synthesis method thereof through allylic Michael addition-cyclization synthesis. Background Art

[0002] Substances with a cyclohexene carboxaldehyde skeleton structure are highly valued by the perfume industry as synthetic fragrances due to their strong green and aldehyde aromas and good chemical stability. They are used in large quantities. Ligustral and Myraldene, which were introduced to China in the 1970s, are two representative substances [Shu Hongfu. Synthesis and aroma characteristics of cyclohexene carboxaldehyde derivatives [J]. Flavors, Fragrances and Cosmetics, 1991 (2): 54-61.]. If the aldehyde group is replaced by a hydroxymethyl, cyano or ester group, the fragrance will change from green to floral and fruity; if a hydroxyl or epoxy group is introduced from the side chain, the product will mainly have a floral fragrance, which provides a lot of possibilities for the development of perfume.

[0003] The synthesis of cyclohexene carboxaldehyde compounds mainly utilizes the Diels-Alder reaction, using dienophiles and conjugated dienes for diene condensation [Wang Yujie, Wei Changnan. Research progress in asymmetric Diels-Alder reactions in organic catalysis [J]. Fine and Specialty Chemicals, 2011, 19(11): 41-45.]. The presence of electron-withdrawing groups on the dienophile or electron-donating groups on the conjugated diene will accelerate the reaction. In general, the reaction requires heating and is often carried out in a closed autoclave [Yin Donghong, Yin Dulin, Fu Zaihui. Preparation of ZnCl2 / NaY catalyst by microwave solid phase method and its catalytic performance in the Diels-Alder reaction of myrcene [J]. Journal of Catalysis, 1999, 20(4): 419-422.], which is mainly suitable for dienophiles with lower molecular weight, such as ketones, carboxylates, nitriles, etc. When the dienophile is a β-β disubstituted compound, the situation is more complicated and the reaction is more difficult under heating conditions. At this time, it is only necessary to carry out the reaction at room temperature and select Lewis acid as a catalyst [Xu Wenyuan, Du Ruihuan, Long Wei. New progress in theoretical research on Diels-Alder reaction [J]. Journal of East China Jiaotong University, 2011, 28(3): 60-64.12.].

[0004] The invention obtains a new 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative by synthesis, and studies the antibacterial activity thereof. Summary of the invention

[0005] The first object of the present invention is to provide a new compound having antibacterial activity.

[0006] A 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative having antibacterial activity, the structural formula of which is:

[0007]

[0008] in,

[0009] R 1 is: hydrogen, halogen, trifluoromethyl, C1-C4 alkyl or C1-C4 alkoxy; R 2 is: hydrogen, C1-C4 alkyl, substituted or unsubstituted phenyl, the substituent on the phenyl is halogen or C1-C4 alkyl; R 3 is: hydrogen or phenyl; preferably, R 1 is: hydrogen, fluorine, chlorine, bromine, trifluoromethyl, methyl or methoxy; R 2 is: hydrogen, methyl, ethyl, propyl, substituted or unsubstituted phenyl, wherein the substituent on the phenyl is chlorine or methyl; R 3 Yes: hydrogen or phenyl.

[0010] Another object of the present invention is to provide a method for synthesizing the above-mentioned 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative with antibacterial activity, which method has simple and readily available raw materials, is inexpensive, is easy to operate, and is convenient for post-processing, and is suitable for industrial production.

[0011] A method for synthesizing a 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative having antibacterial activity, characterized in that the method uses a 2-(2-bromo-1-phenyl)malononitrile derivative (1) and an α,β-unsaturated aldehyde as raw materials, reacts in an organic solvent for 24 hours under the catalysis of a catalyst, and obtains a 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative (2) having antibacterial activity through an allylic Michael addition-cyclization reaction. The reaction formula is as follows:

[0012]

[0013] in,

[0014] R 1 , R 2 , R 3 is defined as above.

[0015] Furthermore, the feed ratio of the raw materials in the synthesis method is calculated as follows: 2-(2-bromo-1-phenyl)malononitrile: α,β-unsaturated aldehyde = 1:4-6.

[0016] The synthesis method comprises the following steps: dissolving a 2-(2-bromo-1-phenyl)malononitrile derivative and an α,β-unsaturated aldehyde in an organic solvent, and reacting at room temperature to obtain the 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative.

[0017] The synthesis method also includes the step of separating and purifying the 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative obtained by the reaction: column chromatography is performed on the reaction product using a solution with a volume ratio of petroleum ether:ethyl acetate = 6:1 to 10:1.

[0018] The organic solvent is tetrahydrofuran.

[0019] The advantages of the synthesis method of the present invention are mainly reflected in: starting from the easily available 2-(2-bromo-1-phenyl)malononitrile derivative (1), under the catalysis of L-proline, tetrahydrofuran is selected as the reaction solvent, and the 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative (2) is simply and quickly prepared through the allylic Michael addition-cyclization reaction, and the product purity is more than 98%. The operation steps of the present invention are simple, that is, the one-pot preparation is carried out, the raw materials are cheap and easy to obtain, the reaction conditions are green and mild, the post-treatment is simple and the yield is high. The reaction conditions of the present invention can also be applied to mass preparation, and are suitable for the industrial production of the 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative (2), so it has high implementation value and potential social and economic benefits.

[0020] The last object of the present invention is to provide the use of 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivatives in the preparation of antibacterial agents, wherein the active ingredient of the antibacterial agent comprises the 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivatives.

[0021] A large number of antibacterial experiments have shown that the 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative of the present invention can be used as an antibacterial agent, especially to have a certain inhibitory effect on wheat fusarium, apple rot bacteria, etc. As a further preference, the 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative is compound 2f, and the antibacterial agent is used to inhibit wheat fusarium; or the 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative is compound 2g, and the antibacterial agent is used to inhibit apple rot bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the nuclear magnetic resonance spectrum of compound 2a;

[0023] Figure 2 is the NMR spectrum of compound 2b. DETAILED DESCRIPTION

[0024] The technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0025] The present invention is further described in detail in conjunction with the following specific examples and drawings, and the protection content of the present invention is not limited to the following examples. Without violating the spirit and scope of the inventive concept, the changes and advantages that can be thought of by those skilled in the art are included in the present invention, and the attached claims are the scope of protection. The process, conditions, reagents, test methods, etc. for implementing the present invention, except for the contents specifically mentioned below, are all common knowledge and common common sense in the art, and the present invention has no special restrictions.

[0026] The test instruments used in the present invention are as follows:

[0027]

[0028] Embodiment 1:

[0029] 2-(2-Bromo-1-phenylethylidene)malononitrile (1.0 mmol), α,β-unsaturated aldehyde (5.0 mmol) and L-proline (0.5 mmol) were dissolved in tetrahydrofuran (1.0 mL), stirred at room temperature for 24 hours, and monitored by TLC until the reaction of the raw materials was complete. The solvent was removed by rotary evaporation under reduced pressure to obtain a crude product, whose structure is shown in Formula 2a.

[0030]

[0031] The crude product was subjected to column chromatography (petroleum ether: ethyl acetate = 10:1) to obtain pure product 2a. The yield was 55%. The product structure was identified by nuclear magnetic resonance and high-resolution mass spectrometry. 1 H NMR(600MHz, CDCl3)δ9.03(d,J=5.4Hz,1H),7.57–7.52(m,3H),7.36(t,J=7.2Hz,2H),7.31(dd,J=14.2,7.2Hz, 3H),7.26–7.23(m,2H),3.75(dd,J=6.4,4.8Hz,1H),3.02(dd,J=9.7,6.5Hz,1H),2.48(dt,J=10.0,5.1Hz,1H). 13 C NMR (151MHz, CDCl3) δ195.7,176.6,132.1,131.5,129.4,129.1,128.9,128.4,127.5,111.9,111.6,88.0,37.8,34.1,30.5.ESI-HRMS calcd for:C 20 H 15 BrN2NaO+ 401.0260, found 401.0271. It indicates that the obtained 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative has the structure shown in structural formula 2a.

[0032] Embodiment 2:

[0033] 2-(2-Bromo-1-(4-methylphenylethylidene))malononitrile (1.0 mmol), 4-methyl-α,β-unsaturated aldehyde (5.0 mmol) and L-proline (0.5 mmol) were dissolved in tetrahydrofuran (1.0 mL), stirred at room temperature for 24 hours, and monitored by TLC until the reaction of the raw materials was complete. The solvent was removed by rotary evaporation under reduced pressure to obtain a crude product, the structure of which is shown in FIG.

[0034] As shown in formula 2b.

[0035]

[0036] The crude product was subjected to column chromatography (petroleum ether: ethyl acetate = 9:1) to obtain pure product 2b with a yield of 51%. The product structure was identified by nuclear magnetic resonance and high-resolution mass spectrometry. 1 H NMR (600MHz, CDCl3) δ9.02 (d, J = 5.4Hz, 1H), 7.36 (t, J = 7.2Hz, 2H), 7.31 (dd, J = 15.1, 7.8Hz, 5H), 7.15 (d, J = 8. 1Hz, 2H), 3.72 (dd, J=6.4, 4.9Hz, 1H), 3.03 (dd, J=9.6, 6.6Hz, 1H), 2.48 (dt, J=10.0, 5.1Hz, 1H), 2.42 (s, 3H). 13 C NMR (151MHz, CDCl3) δ195.8,176.8,142.3,132.3,130.1,129.1,128.9,128.7,128.3,127.5,112.1,111.9,87.4,37.8,34.2,30.5,21.5.ESI-HRMS calcd for:C 21 H 17 BrN2NaO + 415.0416, found 415.0421. This indicates that the obtained 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative has the structure shown in Structural Formula 2b.

[0037] Embodiment 3:

[0038] 2-(2-Bromo-1-(4-chlorophenylethylidene))malononitrile (1.0 mmol), 4-chloro α, β-unsaturated aldehyde (5.0 mmol) and L-proline (0.5 mmol) were dissolved in tetrahydrofuran (1.0 mL), stirred at room temperature for 24 hours, and monitored by TLC until the reaction of the raw materials was complete. The solvent was removed by rotary evaporation under reduced pressure to obtain a crude product, whose structure is shown in Formula 2c.

[0039]

[0040] The crude product was subjected to column chromatography (petroleum ether: ethyl acetate = 10:1) to obtain pure product 2c with a yield of 60%. The product structure was identified by nuclear magnetic resonance and high-resolution mass spectrometry. 1 H NMR (600MHz, CDCl3) δ9.04(d,J=5.2Hz,1H),7.53(d,J=8.3Hz,2H),7.36(t,J=7.3Hz,2H),7.33(d,J=7.0Hz,1H),7.29 (d,J=7.4Hz,2H),7.22(d,J=8.3Hz,2H),3.76–3.70(m,1H),3.00(dd,J=9.4,6.8Hz,1H),2.46(dt,J=9.9,5.0Hz,1H). 13 C NMR (151MHz, CDCl3) δ195.3,175.2,138.2,131.9,129.9,129.2,129.0,128.8,128.5,118.4,111.7,111.5,88.3,37.8,34.2,30.3.ESI-HRMS calcd for:C 20 H 14 BrClN2NaO + 434.9870, found434.9879. This indicates that the obtained 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative has the structure shown in structural formula 2c.

[0041] Embodiment 4:

[0042] 2-(2-Bromo-1-(2-chlorophenylethylidene))malononitrile (1.0 mmol), α,β-unsaturated aldehyde (5.0 mmol) and L-proline (0.5 mmol) were dissolved in tetrahydrofuran (1.0 mL), stirred at room temperature (normal temperature) for 24 hours, followed by TLC until the reaction of the raw materials was complete, and the solvent was removed by rotary evaporation under reduced pressure to obtain a crude product, whose structure is shown in Formula 2d.

[0043]

[0044] The crude product was subjected to column chromatography (petroleum ether: ethyl acetate = 8:1) to obtain pure product 2d with a yield of 48%. The product structure was identified by nuclear magnetic resonance and high-resolution mass spectrometry. 1 H NMR (600MHz, CDCl3) δ9.03(dd,J=38.1,5.4Hz,1H),7.58–7.48(m,2H),7.48–7.42(m,1H),7.34(d,J=7.4Hz,2H),7.30(dd,J=13. 4,6.1Hz,3H),7.14(d,J=7.5Hz,1H),3.82–3.69(m,1H),2.94(ddd,J=61.3,9.5,6.5Hz,1H),2.39(ddt,J=52.6,9.8,5.0Hz,1H). 13 C NMR (151MHz, CDCl3) δ195.5,174.8,132.5,130.9,130.7,129.0,128.4,127.8,127.7,111.4,89.8,38.3,34.6,30.9.ESI-HRMScalcd for:C 20 H 14 BrClN2NaO + 434.9870, found 434.9888. This indicates that the obtained 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative has the structure shown in structural formula 2d.

[0045] Embodiment 5:

[0046] 2-(2-Bromo-1-phenylethylidene)malononitrile (1.0 mmol), acrolein (5.0 mmol) and L-proline (0.5 mmol) were dissolved in tetrahydrofuran (1.0 mL), stirred at room temperature (normal temperature) for 24 hours, and monitored by TLC until the reaction of the raw materials was complete. The solvent was removed by rotary evaporation under reduced pressure to obtain a crude product, whose structure is shown in Formula 2e.

[0047]

[0048] The crude product was subjected to column chromatography (petroleum ether: ethyl acetate = 8:1) to obtain pure product 2e with a yield of 55%. The product structure was identified by nuclear magnetic resonance and high-resolution mass spectrometry. 1H NMR(600MHz, CDCl3)δ9.82(d,J=2.8Hz,1H),7.65–7.61(m,1H),7.61–7.57(m,2H),7.54(d,J=5.4Hz,1H),7.53– 7.51(m,1H),2.27(ddd,J=9.1,6.4,2.9Hz,1H),1.83(t,J=6.0Hz,1H),1.70(s,3H),1.35(dd,J=8.7,5.6Hz,1H). 13 C NMR (151MHz, CDCl3) δ198.0,179.8,134.3,133.0,129.4,129.0,128.3,112.9,112.41,87.56,35.38,34.7,25.67,22.34,19.14.ESI-HRMS calcd for:C 15 H 13 BrN2NaO + 339.0103, found 339.0112. This indicates that the obtained 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative has the structure shown in structural formula 2e.

[0049] Embodiment 6:

[0050] 2-(2-Bromo-1-(4-fluorophenylpropylidene))malononitrile (1.0 mmol), acrolein (5.0 mmol) and L-proline (0.5 mmol) were dissolved in tetrahydrofuran (1.0 mL), stirred at room temperature (normal temperature) for 24 hours, followed by TLC until the reaction of the raw materials was complete, and the solvent was removed by rotary evaporation under reduced pressure to obtain a crude product, whose structure is shown in Formula 2f.

[0051]

[0052] The crude product was subjected to column chromatography (petroleum ether: ethyl acetate = 8:1) to obtain the pure product 2f with a yield of 67%. The product structure was identified by nuclear magnetic resonance and high-resolution mass spectrometry 1 H NMR(600MHz, CDCl3)δ9.82(d,J=2.9Hz,1H),7.71–7.65(m,2H),7.26–7.20(m,2H),2.28( ddd,J=9.0,6.4,2.9Hz,1H),1.87–1.81(m,1H),1.69(s,3H),1.35(dd,J=8.9,5.6Hz,1H). 13C NMR (151MHz, CDCl3) δ197.9,178.2,166.1,164.4,131.1,116.9,116.8,112.8,112.3,35.3,34.5,22.3,19.12.ESI-HRMS calcdfor:C 15 H 12 BrFN2NaO + 357.0009, found 357.0011. This indicates that the obtained 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative has the structure shown in structural formula 2f.

[0053] Embodiment 7:

[0054] 2-(2-Bromo-1-(3-chlorophenylpropylidene))malononitrile (1.0 mmol), acrolein (5.0 mmol) and L-proline (0.5 mmol) were dissolved in tetrahydrofuran (1.0 mL), stirred at room temperature (normal temperature) for 24 hours, followed by TLC until the reaction of the raw materials was complete, and the solvent was removed by rotary evaporation under reduced pressure to obtain a crude product, whose structure is shown in Formula 2g.

[0055]

[0056] The crude product was subjected to column chromatography (petroleum ether: ethyl acetate = 8:1) to obtain 2 g of pure product with a yield of 48%. The product structure was identified by nuclear magnetic resonance and high-resolution mass spectrometry 1 H NMR(600MHz, CDCl3)δ9.81(d,J=2.8Hz,1H),7.55(dd,J=4.9,1.4Hz,2H),7.50–7.45(m,2H),2.3 0(ddd,J=9.1,6.4,2.8Hz,1H),1.82(t,J=6.0Hz,1H),1.68(s,3H),1.35(dd,J=8.9,5.7Hz,1H). 13 C NMR (151MHz, CDCl3) δ197.7,178.1,135.9,135.5,132.6,130.7,127.9,126.3,112.2,111.9,88.9,35.1,34.4,22.0,18.8.ESI-HRMS calcd for:C 15 H 12 BrClN2NaO + 372.9714, found 372.9721. This indicates that the obtained 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative has the structure shown in Structural Formula 2g.

[0057] Example 8: Antibacterial test

[0058] The activity of compounds (2a-g) in inhibiting the growth of plant pathogenic fungal hyphae was determined by the growth rate method. Preparation of culture medium containing different compounds: All the test compounds weighed quantitatively were dissolved in acetone to prepare a mother solution with a concentration of 0.5 mg / mL. 1 mL of mother solution and 9 mL of MEA culture medium were respectively taken into sterile test tubes, and after sufficient shaking, they were poured into sterile culture dishes so that the final mass concentration of the compound in the culture medium was 50 μg / mL, and an equal amount of acetone was used as a blank control. The activated plant pathogenic fungi were punched into a bacterial cake with a diameter of 5 mm with a sterile cork puncher and aseptically inoculated into the above-mentioned culture medium containing the test compound. Each treatment was repeated 3 times. After culturing in the dark at 28°C for 3-7 days, the colony expansion diameter of the test bacteria was measured by "crossing". The formula for calculating the growth inhibition rate is as follows:

[0059] Colony diameter (mm) = average diameter of measured colonies - 5 (initial diameter of the bacterial cake)

[0060]

[0061] The IC of synthetic compounds for inhibiting fungal hyphae growth was calculated using the dose logarithm-inhibition rate probability value method 50 Value (concentration that inhibits mycelial growth by 50%).

[0062] As shown in Table 1, all compounds 2a-g have inhibitory activity against five fungi: rice sheath blight, bitter melon wilt, tomato early blight, apple rot, and wheat fusarium sphaeroides, especially against apple rot and wheat fusarium sphaeroides.

[0063] Table 1. Inhibitory effects of different compounds on five plant pathogenic fungi at the same concentration (concentration of 50 μg / mL)

[0064]

[0065] Next, compounds 2f and 2g were prepared at different concentrations to test against two bacteria, i.e., apple rot pathogen and wheat fusarium, and the IC50 (minimum inhibitory concentration) values ​​were obtained. The two IC50 values ​​in Table 2 are less than 100, where 2f has a good inhibitory effect on wheat fusarium, while 2g performs well against apple rot pathogen.

[0066] Table 2. Specific inhibitory effects of two plant pathogenic fungi

[0067]

Claims

1. A 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative having antibacterial activity, the structural formula of which is: in, R 1 is: hydrogen, halogen, trifluoromethyl, C1-C4 alkyl or C1-C4 alkoxy; R 2 is: hydrogen, C1-C4 alkyl, substituted or unsubstituted phenyl, the substituent on the phenyl is halogen or C1-C4 alkyl; R 3 Yes: hydrogen or phenyl.

2. The 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative having antibacterial activity according to claim 1, characterized in that: The R 1 is: hydrogen, fluorine, chlorine, bromine, trifluoromethyl, methyl or methoxy; R 2 is: hydrogen, methyl, ethyl, propyl, substituted or unsubstituted phenyl, wherein the substituent on the phenyl is chlorine or methyl; R 3 Yes: hydrogen or phenyl.

3. A method for synthesizing the 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative having antibacterial activity as claimed in claim 1 or 2, characterized in that: The method uses a 2-(2-bromo-1-phenyl)malononitrile derivative (1) and an α,β-unsaturated aldehyde as raw materials, reacts in an organic solvent for 24 hours under the catalysis of a catalyst, and obtains a 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative (2) having antibacterial activity through an allylic Michael addition-cyclization reaction. The reaction formula is as follows: in, R 1 , R 2 and R 3 The definition as claimed in claim 1 or 2.

4. The synthesis method according to claim 3, characterized in that The feed ratio of the raw materials in the synthesis method is calculated as follows: 2-(2-bromo-1-phenyl)malononitrile derivative: α, β-unsaturated aldehyde = 1:4-6.

5. The synthesis method according to claim 3, characterized in that The synthesis method comprises the following steps: dissolving a 2-(2-bromo-1-phenyl)malononitrile derivative and an α,β-unsaturated aldehyde in an organic solvent, and reacting at room temperature to obtain the 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative.

6. The synthesis method according to claim 3, characterized in that The synthesis method also includes the step of separating and purifying the 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative obtained by the reaction: column chromatography is performed on the reaction product using a solution with a volume ratio of petroleum ether:ethyl acetate = 6:1 to 10:

1.

7. The synthesis method according to claim 3, characterized in that The organic solvent is tetrahydrofuran.

8. The synthesis method according to claim 3, characterized in that The catalyst is L-proline, and the structural formula is as follows:

9. Use of the 1-nitrile-3-bromo-6-imine-5-cyclohexenecarboxaldehyde derivative as claimed in claim 1 or 2 in the preparation of an antibacterial agent, characterized in that: The active ingredient of the antibacterial agent comprises the 1-nitrile-3-bromo-6-imine-5-cyclohexene carboxaldehyde derivative according to claim 1 or 2.

10. The use according to claim 9, characterized in that: The antibacterial agent is used for inhibiting one or more of wheat fusarium rust bacteria and apple rot bacteria.

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