CN111285815A - Pyrazinamide compound and application thereof - Google Patents

Abstract

The invention belongs to the field of bactericides. Relates to a pyrazinamide compound and a sterilization application thereof. The pyrazinamide compound is shown as a general formula I:

Description

A kind of pyrazinamide compound and use

technical field

The present invention belongs to the field of fungicides. The invention relates to a pyrazinamide compound and its bactericidal use.

Background technique

Since diseases can develop resistance to fungicides over a period of time, there is a continuing need to invent new and improved compounds and compositions with fungicidal activity.

The bactericidal activity of amide compounds has been reported. For example, WO2015074614A1 discloses compound KC (compound 9 in the patent) and its bactericidal activity.

In the prior art, there is no report on the pyrazinamide compounds whose structure is shown in the general formula I of the present invention.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a pyrazinamide compound with better bactericidal activity, which can be applied to the prevention and treatment of agricultural diseases.

For achieving the above object, technical scheme of the present invention is as follows:

Pyrazinamide compounds are shown in general formula I,

where:

R ₁ is selected from hydrogen, halogen, nitro, cyano, C ₁ -C ₁₂ alkyl or C ₁ -C ₁₂ haloalkyl;

R ₂ is selected from C ₁ -C ₁₂ alkyl;

The compound represented by the general formula I can also be a chiral compound, and the configuration of the chiral compound is selected from R configuration, S configuration or RS mixed configuration.

Preferred technical scheme in the present invention is, in general formula I:

R ₁ is selected from hydrogen, halogen, C ₁ -C ₆ alkyl or C ₁ -C ₆ haloalkyl;

R ₂ is selected from C ₁ -C ₈ alkyl;

Or, the chiral compound represented by the general formula I, the configuration of the chiral compound is selected from R configuration, S configuration or RS mixture.

Further preferred technical scheme in the present invention is, in general formula I:

R ₁ is selected from hydrogen, fluorine, chlorine, bromine, iodine, methyl, ethyl, propyl, isopropyl, difluoromethyl, trifluoromethyl, pentafluoroethyl or heptafluoroisopropyl;

R is selected from methyl, ethyl, propyl, isopropyl, butyl, ₂ -butyl, pentyl, 2-pentyl, hexyl or 2-hexyl,;

Or, the chiral compound represented by the general formula I, the configuration of the chiral compound is selected from R configuration, S configuration or RS mixture.

Particularly preferred technical scheme in the present invention is, in general formula I:

R ₁ is selected from hydrogen, fluorine, chlorine, bromine, methyl or trifluoromethyl;

R ₂ is selected from 2-pentyl or 2-hexyl;

Or, the chiral compound represented by the general formula I, the configuration of the chiral compound is selected from R configuration, S configuration or RS mixture.

In the definitions of compounds of general formula I given above, the terms used collectively are generally defined as follows:

Alkyl refers to straight or branched chain forms such as methyl, ethyl, n-propyl, isopropyl, and the like. Haloalkyl refers to a group in which the alkyl group is substituted with one or more halogen atoms, such as chloroethyl, trifluoromethyl, difluoromethyl, heptafluoroisopropyl, and the like. Halogen means fluorine, chlorine, bromine, iodine.

The preparation method of the compound of general formula I, unless otherwise noted, the definitions of each group in the reaction formula are the same as before.

In the formula, L represents a leaving group.

Compound I is prepared by reacting the compound of general formula II with the compound of general formula III (commercially available) in a suitable solvent and in the presence of a suitable base at a temperature of -10°C to the boiling point of the suitable solvent for 0.5-48 hours.

Suitable solvents are selected from methylene chloride, chloroform, carbon tetrachloride, hexane, benzene, toluene, ethyl acetate, acetonitrile, tetrahydrofuran, dioxane, N,N-dimethylformamide or dimethylmethylene Sulfone etc.

Suitable bases include alkali metal such as lithium, sodium or potassium hydrogen compounds such as sodium hydride, alkali metal such as lithium, sodium or potassium hydroxide such as sodium hydroxide, and also alkali metal carbonates such as sodium carbonate, It can be an organic base such as triethylamine, sodium tert-butoxide and the like.

Compounds of general formula II are commercially available reagents or prepared from their corresponding acids.

The compound of general formula III can be prepared by referring to the following documents: Bioorganic & Medicinal Chemistry, 2012, 20(3): 1213-1221; WO2005117909; Pesticide, 2007, 46(5): 307-309.

Table 1 lists the structures and physical properties of some of the compounds of general formula I.

Table 1 Partial Structure and Physical Properties of Compounds of Formula I

The ¹ H NMR (600 MHz, CDCl ₃ ) data of some compounds are as follows:

Compound 6: 9.93(s, 1H), 8.67(d, J=2.3Hz, 1H), 8.45(d, J=2.1Hz, 1H), 7.78(d, J=8.2Hz, 1H), 7.23(t, J=8.2Hz, 1H), 6.74(d, J=8.2Hz, 1H), 3.86(s, 3H), 3.07(s, 3H), 2.25(s, 3H).

Compound 43: 9.92(s, 1H), 8.67(d, J=2.3Hz, 1H), 8.46(d, J=2.2Hz, 1H), 7.77(d, J=8.1Hz, 1H), 7.20(t, J=8.2Hz, 1H), 6.72(d, J=8.2Hz, 1H), 4.06(q, J=7.0Hz, 2H), 3.07(s, 3H), 2.25(s, 3H).

Compound 117: 9.91(s, 1H), 8.66(d, J=2.3Hz, 1H), 8.45(d, J=2.0Hz, 1H), 7.76(d, J=8.1Hz, 1H), 7.19(t, J=8.2Hz, 1H), 6.74(d, J=8.2Hz, 1H), 4.53(dt, J1 _{= 12.1Hz} , J2=6.0Hz, 1H), 3.07(s, 3H), 2.24(s, 3H),1.35(d,J=6.1Hz,6H).

Compound 191: 9.91(s, 1H), 8.66(d, J=2.3Hz, 1H), 8.45(d, J=2.1Hz, 1H), 7.75(d, J=8.1Hz, 1H), 7.19(t, J=8.2Hz, 1H), 6.73(d, J=8.2Hz, 1H), 4.32(dt, J1 ₌ 12.0Hz, J2=6.0Hz, 1H ₎ , 3.07(s, 3H), 2.24(s, 3H), 1.83-1.72(m, 1H), 1.71-1.61(m, 1H), 1.30(d, J=6.1Hz, 3H), 0.99(t, J=7.5Hz, 3H).

Compound 260: 9.71(s, 1H), 9.52(d, J=1.3Hz, 1H), 8.81(d, J=2.4Hz, 1H), 8.61-8.59(m, 1H), 7.81(d, J=8.1 Hz, 1H), 7.20(t, J=8.2Hz, 1H), 6.74(d, J=8.2Hz, 1H), 4.39(dd, J1 _{= 12.1Hz} , J2=6.1Hz, 1H), 2.26( s,3H),1.80-1.72(m,1H),1.62-1.54(m,1H),1.53-1.38(m,2H),1.30(d,J=6.1Hz,3H),0.95(t,J= 7.4Hz, 3H).

Compound 262: 9.56(s, 1H), 8.61(d, J=2.3Hz, 1H), 8.57(d, J=2.3Hz, 1H), 7.77(d, J=8.1Hz, 1H), 7.20(t, J=8.2Hz,1H),6.75(d,J=8.2Hz,1H),4.39(dd,J1 _{= 12.1Hz} ,J2=6.1Hz,1H),2.23(s,3H),1.80-1.70( m, 1H), 1.63-1.54 (m, 1H), 1.53-1.37 (m, 2H), 1.30 (d, J=6.1Hz, 3H), 0.95 (t, J=7.3Hz, 3H).

Compound 265: 8.66 (s, 1H), 8.45 (s, 1H), 7.74 (d, J=8.1 Hz, 1H), 7.19 (t, J=8.2 Hz, 1H), 6.73 (d, J=8.3 Hz, 1H), 4.38(dd, J ₁ =12.1Hz, J ₂ =6.0Hz, 1H), 3.07(s, 3H), 2.24(s, 3H), 1.81-1.67(m, 1H), 1.62-1.54(m ,1H),1.53-1.37(m,2H),1.30(d,J=6.0Hz,3H),0.95(t,J=7.3Hz,3H).

Compound 270: 9.38(s, 1H), 8.88(d, J=2.2Hz, 1H), 8.82(d, J=2.2Hz, 1H), 7.74(d, J=8.1Hz, 1H), 7.19(t, J=8.2Hz, 1H), 6.75(d, J=8.2Hz, 1H), 4.39(dd, J1 _{= 12.1Hz} , J2=6.1Hz, 1H), 2.24(s, 3H), 1.81-1.70( m, 1H), 1.64-1.53 (m, 1H), 1.51-1.38 (m, 2H), 1.30 (d, J=6.1Hz, 3H), 0.95 (t, J=7.4Hz, 3H).

Compound 274: 9.51(s, 1H), 9.28(s, 1H), 8.60(s, 1H), 7.76(d, J=8.1Hz, 1H), 7.20(t, J=8.2Hz, 1H), 6.75( d, J=8.3Hz, 1H), 4.39 (dd, J1 ₌ 12.1Hz, J2=6.1Hz, 1H), 2.24(s, 3H), _1.83-1.69 (m, 1H), 1.62-1.55(m ,1H),1.53-1.39(m,2H),1.30(d,J=6.1Hz,3H),0.95(t,J=7.4Hz,3H).

Compound 277: 9.67(s, 1H), 9.38(s, 1H), 8.46(s, 1H), 7.81(d, J=8.1Hz, 1H), 7.20(t, J=8.2Hz, 1H), 6.73( d, J=8.2Hz, 1H), 4.39 (dd, J1 ₌ 12.1Hz, J2=6.1Hz, 1H), 2.69(s, 3H), _2.25 (s, 3H), 1.80-1.71(m, 1H) ),1.62-1.54(m,1H),1.53-1.39(m,2H),1.30(d,J=6.1Hz,3H),0.95(t,J=7.3Hz,3H).

Compound 286: 9.42(s, 1H), 9.39(s, 1H), 8.80(s, 1H), 7.69(d, J=8.1Hz, 1H), 7.19(t, J=8.2Hz, 1H), 4.39( dd, J ₁ =12.1Hz, J ₂ =6.0Hz, 1H), 2.24(s, 4H), 1.82-1.71(m, 1H), 1.62-1.55(m, 1H), 1.52-1.39(m, 3H) ,1.30(d,J＝6.1Hz,3H),0.95(t,J＝7.4Hz,3H).

Compound 289: 9.77(s, 1H), 9.31(s, 1H), 8.67(s, 1H), 7.79(d, J=8.1Hz, 1H), 7.20(t, J=8.2Hz, 1H), 6.74( d,J=8.2Hz,1H),4.39(dd,J1 ₌ 12.0Hz,J2=6.0Hz,1H ₎ ,2.67(s,3H),2.26(s,3H),1.80-1.72(m,1H) ),1.63-1.54(m,1H),1.52-1.39(m,2H),1.30(d,J=6.1Hz,3H),0.95(t,J=7.3Hz,3H).

Compound 334: 9.71(s,1H), 9.52(d,J=0.8Hz,1H), 8.81(d,J=1.6Hz,1H), 8.61-8.60(m,1H), 7.81(d,J=5.2 Hz, 1H), 7.20(t, J=5.6Hz, 1H), 6.74(d, J=5.6Hz, 1H), 4.39-4.36(m, 1H), 2.26(s, 3H), 1.80-1.72(m ,2H),1.62-1.54(m,2H),1.53-1.38(m,2H),1.30(d,J=6.1Hz,3H),0.95(t,J=7.4Hz,3H).

Compound 336: 9.56(s, 1H), 8.60(d, J=2.3Hz, 1H), 8.57(d, J=2.3Hz, 1H), 7.77(d, J=8.3Hz, 1H), 7.19(t, J=8.2Hz, 1H), 6.74 (d, J=8.4Hz, 1H), 4.37 (dd, J1 _{= 12.1Hz} , J2=6.1Hz, 1H), 2.24 (d, J=3.1Hz, 3H) ,1.80-1.73(m,1H),1.72-1.65(m,1H),1.64-1.57(m,1H),1.51-1.41(m,1H),1.40-1.32(m,2H),1.30(d, J=6.1Hz, 3H), 0.91(t, J=7.1Hz, 3H).

Compound 339: 9.91(s, 1H), 8.66(d, J=2.3Hz, 1H), 8.45(d, J=2.1Hz, 1H), 7.75(d, J=8.3Hz, 1H), 7.19(t, J=8.2Hz, 1H), 6.73(d, J=8.3Hz, 1H), 4.37(dd, J1 _{= 12.1Hz} , J2=6.1Hz, 1H), 3.07(s, 3H), 2.24(s, 2H), 1.80-1.74(m, 1H), 1.72-1.66(m, 1H), 1.65-1.58(m, 1H), 1.48-1.41(m, 1H), 1.40-1.33(m, 2H), 1.30( d,J=6.1Hz,3H),0.91(t,J=7.1Hz,3H).

Compound 344: 9.38(s, 1H), 8.88(d, J=2.2Hz, 1H), 8.82(d, J=2.2Hz, 1H), 7.74(d, J=8.1Hz, 1H), 7.19(t, J=8.2Hz, 1H), 6.75 (d, J=8.4Hz, 1H), 4.37 (dd, J1 _{= 12.1Hz} , J2=6.1Hz, 1H), 2.24 (d, J=3.1Hz, 3H) ,1.81-1.73(m,1H),1.71-1.67(m,1H),1.66-1.57(m,1H),1.49-1.41(m,1H),1.40-1.32(m,2H),1.30(d, J=6.1Hz, 3H), 0.91(t, J=7.1Hz, 3H).

Compound 348: 9.51(s, 1H), 9.27(s, 1H), 8.58(s, 1H), 7.75(t, J=7.9Hz, 1H), 7.19(t, J=8.2Hz, 1H), 6.73( t,J=7.9Hz,1H),4.37(dd,J1 ₌ 12.1Hz,J2=6.1Hz,1H),2.24(d,J=4.0Hz,3H), _1.78-1.74 (m,1H), 1.72-1.66(m, 1H), 1.64-1.55(m, 1H), 1.49-1.41(m, 1H), 1.40-1.33(m, 2H), 1.30(d, J=6.1Hz, 3H), 0.92( t,J=7.1Hz,3H).

Compound 351: 9.67 (s, 1H), 9.37 (d, J=1.0 Hz, 1H), 8.45 (s, 1H), 7.80 (t, J=8.1 Hz, 1H), 7.19 (td, J ₁ =8.2 Hz , J ₂ =2.9Hz,1H),6.72(t,J=8.1Hz,1H),4.37(dd,J ₁ =12.1Hz,J ₂ =6.1Hz,1H),2.68(s,3H),2.25( d, J＝3.7Hz, 3H), 1.81-1.73(m, 1H), 1.72-1.66(m, 1H), 1.65-1.54(m, 1H), 1.50-1.41(m, 1H), 1.39-1.32( m, 2H), 1.30(d, J=6.1Hz, 3H), 0.91(t, J=7.1Hz, 3H).

Compound 360: 9.42(s, 1H), 9.39(s, 1H), 8.80(s, 1H), 7.69(t, J=7.9Hz, 1H), 7.19(t, J=8.2Hz, 1H), 6.74( t,J=8.0Hz,1H),4.37(dd,J1 ₌ 12.1Hz,J2=6.1Hz,1H), _2.25 (d,J=4.3Hz,3H),1.80-1.74(m,1H), 1.72-1.68(m, 1H), 1.64-1.59(m, 1H), 1.49-1.42(m, 1H), 1.40-1.33(m, 2H), 1.30(d, J=6.1Hz, 3H), 0.92( t,J=7.1Hz,3H).

Compound 363: 9.78 (s, 1H), 9.30 (s, 1H), 8.66 (s, 1H), 7.78 (t, J=8.3 Hz, 1H), 7.19 (dd, J ₁ =10.9 Hz, J ₂ =5.5 Hz, 1H), 6.73(t, J=8.2Hz, 1H), 4.37(dd, J1 _{= 12.1Hz} , J2=6.1Hz, 1H), 2.67(s, 3H), 2.26(d, J=4.1 Hz,3H),1.82-1.74(m,1H),1.73-1.68(m,1H),1.66-1.57(m,1H),1.48-1.42(m,1H),1.40-1.33(m,2H), 1.30(d,J=6.1Hz,3H),0.92(t,J=7.1Hz,3H).

Compound 373191: 9.91(s, 1H), 8.66(d, J=2.3Hz, 1H), 8.45(d, J=2.1Hz, 1H), 7.75(d, J=8.1Hz, 1H), 7.19(t, J=8.2Hz, 1H), 6.73(d, J=8.2Hz, 1H), 4.39(dt, J1 ₌ 12.0Hz, J2=6.0Hz, 1H ₎ , 3.07(s, 3H), 2.24(s, 3H), 1.83-1.72(m, 1H), 1.71-1.61(m, 1H), 1.30(d, J=6.1Hz, 3H), 0.95(t, J=7.5Hz, 3H).

Compound 374371191: 9.91(s, 1H), 8.64(d, J=2.3Hz, 1H), 8.43(d, J=2.1Hz, 1H), 7.75(d, J=8.1Hz, 1H), 7.18(t, J=8.2Hz, 1H), 6.73(d, J=8.2Hz, 1H), 4.39(dt, J1 ₌ 12.0Hz, J2=6.0Hz, 1H ₎ , 3.06(s, 3H), 2.24(s, 3H), 1.83-1.72(m, 1H), 1.71-1.61(m, 1H), 1.30(d, J=6.1Hz, 3H), 0.95(t, J=7.5Hz, 3H).

The present invention also includes the use of compounds of general formula I for controlling diseases to control Oomycetes, Ascomycetes, Basidiomycetes, Deuteromycetes, Plasmorhizobium (Plasmodiophoromycetes), Chytridiomycetes and Zygomycetes diseases.

Examples of certain diseases that may be mentioned under the class names listed above include, but are not limited to:

Wheat rust, wheat powdery mildew, wheat scab, wheat root rot, wheat sheath blight, wheat take-all disease, wheat glume blight, cucumber downy mildew, cucumber anthracnose, cucumber fusarium wilt, cucumber gray mold, Grape downy mildew, tomato early blight, tomato late blight, rice sheath blight, rice blast, watermelon blight, peanut scab, peanut black spot, citrus scab, pepper root rot, cotton verticillium wilt, Cotton fusarium wilt, rape black stem disease, rape sclerotinia, pear scab, ginseng rust, corn rust, corn curvaceous disease, corn leaf spot, mango stalk rot, apple ring rot, apple rot fungus Rot, banana leaf spot.

The present invention also includes fungicidal compositions comprising a compound of general formula I as an active ingredient. The weight percent content of the compound of formula I as an active component in the bactericidal composition is between 1-99%. An agriculturally acceptable carrier is also included in the fungicidal composition.

The compositions of the present invention can be administered in the form of formulations. The compound of formula I is dissolved or dispersed as the active ingredient in a carrier or formulated so as to be easier to disperse for bactericidal use. For example, these chemicals can be formulated as wettable powders or emulsifiable concentrates. In these compositions, at least one liquid or solid carrier is added, and when desired, suitable surfactants can be added.

The technical solution of the present invention also includes a method for preventing and treating diseases: applying the bactericidal composition of the present invention to the disease or its growth medium. A more suitable effective amount is usually selected from 10 grams to 1000 grams per hectare.

For certain applications, such as in agriculture, one or more other insecticides, fungicides, herbicides, plant growth regulators or fertilizers, etc. may be added to the fungicidal compositions of the present invention, thereby producing additional Advantages and Effects.

The advantages of the present invention:

Compared with the known pyrazinamide compounds, the compound of the present invention has a novel structure, and the pyrazinamide compound of the present invention has an unexpected high bactericidal activity, and also has a high bactericidal activity at a lower dose, and is not only efficient, Moreover, the use of pesticides is reduced, the cost is reduced, and the pollution to the environment is reduced.

Detailed ways

The following synthesis examples and biological activity assay examples can be used to further illustrate the present invention, but are not intended to limit the present invention.

Synthesis Example

Preparation of Example 1 Compound 270:

3-methylpyrazine-2-carboxylic acid (200 mg, 1.04 mmol), 10 ml of toluene and 1 ml of thionyl chloride were added to the reaction flask, and the reaction was refluxed for 2 hours, and the excess thionyl chloride and solvent were removed for use. . 2-Methyl-3-(pentyl-2-oxy)aniline (201 mg, 1.04 mmol) was dissolved in 10 mL of dichloromethane and 1 mL of triethylamine was added. The prepared acid chloride was dissolved in dichloromethane, added dropwise to the above mixture, and reacted at room temperature for 2 hours. The reaction solution was poured into 30 ml of water, extracted three times with dichloromethane, and the organic layer was taken. The organic layer was washed successively with saturated aqueous sodium bicarbonate solution and saturated brine, dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by column chromatography (eluent: ethyl acetate: petroleum ether=1:5) to obtain 230 mg of compound 270 in a yield of 55.7%.

Preparation of Example 2 Compound 344:

3-methylpyrazine-2-carboxylic acid (200 mg, 1.04 mmol), 10 ml of toluene and 1 ml of thionyl chloride were added to the reaction flask, and the reaction was refluxed for 2 hours, and the excess thionyl chloride and solvent were removed for use. . 2-Methyl-3-(hexyl-2-oxy)aniline (216 mg, 1.04 mmol) was dissolved in 10 mL of dichloromethane and 1 mL of triethylamine was added. The prepared acid chloride was dissolved in dichloromethane, added dropwise to the above mixture, and reacted at room temperature for 2 hours. The reaction solution was poured into 30 ml of water, extracted three times with dichloromethane, and the organic layer was taken. The organic layer was washed successively with saturated aqueous sodium bicarbonate solution and saturated brine, dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by column chromatography (eluent: ethyl acetate: petroleum ether=1:5) to obtain 190 mg of compound 344 in a yield of 47.5%.

Other compounds of general formula I of the present invention can be synthesized by referring to the above-mentioned methods.

Biological Activity Assay Example

Example 3 Determination of bactericidal activity

The compounds of the present invention obtained above were tested against various diseases of plants. The test method is as follows:

(1) In vivo protection activity test

The test adopts the potted seedling assay method. The two-leaf stage potted cucumber seedlings with consistent growth were selected as the experimental host plants for cucumber downy mildew; the two-leaf stage potted wheat seedlings with consistent growth were selected as the test host plants for wheat powdery mildew, and the two-leaf stage potted maize seedlings with consistent growth were selected as the experimental host plants for cucumber downy mildew. Test host plants for maize rust. Foliar spray treatments were carried out with the compounds of the present invention at the designed concentrations. Another blank control with water spray was set up, repeated three times, and disease inoculation was carried out on the second day after treatment. After inoculation, the plants were placed in an artificial climate chamber for moisturizing cultivation (temperature: 25° C. day, 20° C. night, relative humidity: 95-99%). After culturing the test material for 24 hours, it was transferred to the greenhouse for cultivation, and the plants that did not require moisturizing cultivation were directly inoculated and cultivated in the greenhouse. The compound disease prevention effect was evaluated after sufficient disease onset (usually one week) with controls. Results The survey refers to the "A Manual of Assessment Keys for Plant Diseases" compiled by the American Society of Plant Diseases, with 100 to 0, where "100" represents no disease and "0" represents the most serious disease.

Some of the test results are as follows:

Prevention of corn rust:

According to the above test method, among some of the tested compounds, the following compounds have better control effect on corn rust at a concentration of 400ppm, and the control effect is ≥80%: Compounds 5, 43, 117, 191, 262, 265, 270, 277 , 289, 336, 339, 344, 348, 373 and 374.

According to the above test method, the compounds 270 and 344 and the known compound KC were selected to carry out parallel determination of the control activity of corn rust. The test results are shown in Table 3.

Table 3: Comparison of some compounds of the present invention and known compounds against corn rust

(2) In vitro antibacterial activity test

The determination method is as follows: using a high-throughput screening method, that is, using a suitable solvent (such as acetone, methanol, DMF, etc., and selecting the solvent according to its dissolving ability to the sample) for the sample of the compound to be tested to prepare the desired concentration liquid to be tested. In an ultra-clean working environment, the liquid to be tested was added to the microwells of a 96-well culture plate, and then the pathogenic bacteria propagule suspension was added to it, and the treated culture plate was placed in a constant temperature incubator for cultivation, and the investigation was carried out after 24 hours. . During the investigation, the germination or growth of the propagules of the pathogenic bacteria was visually observed, and the bacteriostatic activity of the compounds was evaluated according to the germination or growth of the control treatment.

The test results of in vitro antibacterial activity (expressed as inhibition rate) of some compounds are as follows:

Rice blast fungus:

Among some of the tested compounds, the following compounds have better control effects at a concentration of 25 ppm, and the inhibition rate is ≥80%: compounds 260, 265, 277, 289, 334, 339, 351 and 363.

Claims (8)

1. a pyrazinamide compound, is characterized in that: compound is as shown in general formula I:

where: R ₁ is selected from hydrogen, halogen, nitro, cyano, C ₁ -C ₁₂ alkyl or C ₁ -C ₁₂ haloalkyl; R ₂ is selected from C ₁ -C ₁₂ alkyl. 2 . The compound according to claim 1 , wherein the compound represented by the general formula I can also be a chiral compound, and the configuration of the chiral compound is selected from R configuration, S configuration or RS mixed configuration. 3 . 3. according to the compound described in claim 1 or 2, it is characterized in that, in general formula I: R ₁ is selected from hydrogen, halogen, C ₁ -C ₆ alkyl or C ₁ -C ₆ haloalkyl; R ₂ is selected from C ₁ -C ₈ alkyl. 4. according to the compound described in claim 3, it is characterized in that, in general formula I: R ₁ is selected from hydrogen, fluorine, chlorine, bromine, iodine, methyl, ethyl, propyl, isopropyl, difluoromethyl, trifluoromethyl, pentafluoroethyl or heptafluoroisopropyl; R2 is selected from methyl, ethyl, propyl, isopropyl, butyl, ₂ -butyl, pentyl, 2-pentyl, hexyl or 2-hexyl. 5. compound according to claim 4 is characterized in that, in general formula I: R ₁ is selected from hydrogen, fluorine, chlorine, bromine, methyl or trifluoromethyl; R ₂ is selected from 2-pentyl or 2-hexyl. 6 . The application of the pyrazinamide compound according to claim 1 , wherein the compound of general formula I is used to prepare a medicine for controlling agricultural, forestry or non-therapeutic plant diseases. 7 . 7. a bactericidal composition is characterized in that: the bactericidal composition is the acceptable carrier of active component and agriculture or forestry with the compound shown in the general formula I described in claim 1, as active component in the composition The weight content of the compound of general formula I is 1-99%. 8. A method for controlling plant diseases, characterized in that: applying the composition according to claim 7 to the disease to be controlled or the medium in which it grows at an effective dose of 10 grams to 1000 grams per hectare.