Diaminobenzoquinone derivatives, their preparation and use as algicides

Abstract

The application (named: a class of diaminobenzoquinone derivatives, preparation and algaecidal purposes thereof) relates to 29 kinds of diaminobenzoquinone derivatives, a preparation method thereof, and an algaecidal purpose. 2-acetylamino-5-substituted amino-p-benzoquinone is prepared by oxidation and amination of 2-acetylamino-1,4-dimethoxybenzene; 2-benzyloxycarbonylamino-5-substituted amino-p-benzoquinone is prepared by benzyloxycarbonylation, oxidation and amination of 2-amino-1,4-dimethoxybenzene. The compounds can be used as algaecides to prevent and control cladophora and microcystis aeruginosa.

Description

Technical Field

[0001] This invention relates to a class of diaminobenzoquinone derivatives and their preparation and uses, specifically to the field of agricultural algaecides. Background Technology

[0002] Abenquine, a diaminobenzoquinone compound, is a secondary metabolite of Streptomyces strain DB634. This type of substance has a strong inhibitory effect on the growth and reproduction of cyanobacteria.

[0003]

[0004] This patent, using abenquinone as a lead compound, designed and synthesized a series of diaminobenzoquinone derivatives. Screening revealed that some compounds exhibited strong algicidal activity. The specific research results are as follows. Summary of the Invention

[0005] The purpose of this invention is to provide a class of diaminobenzoquinone derivatives and their preparation method, which can be applied to agricultural control of aquatic algae.

[0006] The technical solution of the present invention is as follows: The diaminobenzoquinone derivative provided by this invention has the following general structural formula: R 1 Selected from acetyl and benzyloxyformyl.

[0007] Synthesis reaction formula for diaminobenzoquinone derivative I:

[0008] Preparation method of general formula compound I: 2,5-dimethoxyacetanilide (1) was added to a mixed solvent of methanol and water, and phenyliododiacetic acid ester was slowly added under stirring to obtain intermediate compound 2. Compound 2 was added to anhydrous ethanol and reacted with different organic amines in the presence of sodium bicarbonate to obtain the I series of compounds.

[0009]

[0010] Preparation method of general formula compound II: 2,5-dimethoxyaniline (3) and sodium bicarbonate were added to tetrahydrofuran, and benzyl chloroformate (4) was added dropwise under stirring to obtain intermediate compound 5. Compound 5 underwent a reaction similar to that of compound 1 to obtain the II series of compounds. Detailed Implementation

[0011] Preparation of compounds I-1 and II-1

[0012] 2,5-Dimethoxyacetanilide (4.06 g, 20 mmol) was added to a methanol:water mixture (1:4) in 200 mL and stirred until homogenized. Phenyliododiacetic acid ester (10.19 g, 31 mmol) was slowly added, and the mixture was reacted at room temperature for 1 h. The mixture was extracted with dichloromethane, washed with sodium bicarbonate solution, dried over anhydrous sodium sulfate, concentrated, and eluted by silica gel column chromatography with ethyl acetate:petroleum ether (1:5-1:2) to give a yellow solid compound 2.

[0013] Compound 2 (169 mg, 1 mmol) and sodium bicarbonate (89 mg, 1 mmol) were added to anhydrous ethanol (20 mL), and 1-aminoindenhydride (139 mg, 1 mmol) was added dropwise with stirring. The mixture was reacted at room temperature for 30 min, and then an equal volume of water was added. The mixture was extracted with ethyl acetate, dried over anhydrous sodium sulfate, concentrated, and eluted by silica gel column chromatography with ethyl acetate:petroleum ether = 1:15-1:5 to give a dark red solid compound I-1.

[0014]

[0015] 2,5-Dimethoxyaniline (3, 2.36 g, 15.3 mmol) and sodium bicarbonate (1.29 g, 15.4 mmol) were added to tetrahydrofuran (125 mL), stirred, and benzyl chloroformate (4, 3.07 g, 18 mmol) was slowly added dropwise at 0 °C. After 30 min, the mixture was moved to room temperature and reacted for 2 h. The mixture was extracted with ethyl acetate and concentrated to give a gray compound 5.

[0016] Compound 5 was homogenized by stirring in a methanol:water mixture (1:4) (125 mL), and phenyliododiacetic acid ester (7.25 g, 22.5 mmol) was slowly added. The reaction was allowed to proceed at room temperature for 1 h, followed by extraction with dichloromethane, washing with sodium bicarbonate solution, drying over anhydrous sodium sulfate, concentration, and silica gel column chromatography. Elution with ethyl acetate:petroleum ether (1:5–1:1) yielded a yellow solid, compound 6.

[0017] Compound 6 (259 mg, 1 mmol) and sodium bicarbonate (89 mg, 1 mmol) were added to anhydrous ethanol (20 mL), and 1-aminoindenhydride (7, 138 mg, 1 mmol) was added dropwise with stirring. The mixture was reacted at room temperature for 30 min, and then an equal volume of water was added. The mixture was extracted with ethyl acetate, dried over anhydrous sodium sulfate, concentrated, and eluted by silica gel column chromatography with ethyl acetate:petroleum ether = 1:15-1:3 to give a dark red solid compound II-1.

[0018] target compound 1 H NMR and 13 The C NMR data are as follows:

[0019] Example 2: Evaluation of Algicidal Activity There is a correlation between freshwater algal species density and absorbance; algal species density can be obtained by measuring their absorbance. The maximum absorption wavelength of *Scenedesmus obliquus* is 682 nm, and that of *Microcystis aeruginosa* is 678 nm. In the initial stage of the experiment, a hemocytometer was used daily at the same time to observe changes in algal species numbers under a microscope, and the absorbance of each species at its maximum absorption wavelength was measured. After eight consecutive days of measurements, a linear equation between algal density and absorbance was established. Subsequently, only the absorbance at the incident light wavelength needs to be measured, and the corresponding algal density can be obtained by substituting it into the equation.

[0020] 20 mg of the compound was initially weighed and dissolved in 1 mL of DMSO to obtain a stock solution concentration of 20 mg / mL. 40 μL of this stock solution was added to 40 mL of the exponential growth phase algal culture in conical flasks, resulting in a concentration of 20 μg / mL. An equal volume of DMSO was added as a blank control. The control agents were azirconium and diuron. The flasks were incubated in a constant temperature incubator at 4000 lux, a light-dark ratio of 1:1 (12 h light, 12 h dark), and a temperature of 26 ± 2 ℃. After 72 h, the absorbance of *Scenedesmus obliquus* and *Microcystis aeruginosa* was measured. The algal density was converted to algal density using a linear equation relating algal density and absorbance. The inhibition rate was calculated using the following formula: IS (%)=(1− N / N 0)×100 in, IS For inhibition rate, N To determine the algal density of the group to be treated, N 0 represents the algal density of the control group.

[0021] Drugs with inhibition rates greater than the control drug were selected and re-screened at concentrations of 1, 5, 10, 15, and 20 ug / mL to obtain their EC values. 50 The toxicity equations are detailed in Table 1.

[0022] Table 1. Inhibitory effects of some target compounds on Scenedesmus obliquus and Microcystis aeruginosa

Claims

1. A class of diaminobenzoquinone derivatives have the following structures as shown in the general formula: When R 1 =Acetyl group, R 2 Selected from ; When R 1 = benzyloxyformyl group, R 2 Selected from .

2. The compound according to claim 1, characterized in that: Selected from the following compounds: 。 3. The compound according to claim 1, characterized in that: Selected from the following compounds: 。 4. The use of the compound as described in claim 2 in the purpose of killing algae, wherein the algae is Scenedesmus obliquus.

5. The use of the compound of claim 3 in the killing of algae, wherein the algae is Microcystis aeruginosa.

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