DE3816807A1 - 2-substituted 1,3,4-oxa(thia)diazoles, their preparation, and their use as pesticides - Google Patents

Abstract

There are described novel 2-substituted 1,3,4-oxadiazole or 1,3,4-thiadiazole derivatives of the general formula <IMAGE> in which Ar, R1 and X have the meanings given in the description, a process for their preparation, and their use as pesticides. The novel compounds are particularly suitable for use as nematicides.

Description

The invention relates to new 2-substituted 1,3,4-oxadiazole or 1,3,4- thiadiazole derivatives, their preparation and their use as pests pesticides, in particular against nematodes.

Compounds of similar structure with nematicidal activity are already known, such as B. from EP 02 17 747 and 02 63 066.

However, the known compounds have the disadvantage that they are either not sufficiently compatible with plants or not sufficiently effective are.

The object of the present invention was to provide compounds which are particularly effective against nematodes without at the same time to be plant intolerant.

It has now been found that 2-substituted 1,3,4-oxadiazole or 1,3,4- thiadiazole derivatives of the general formula I

wherein
Ar is optionally one or more, the same or different, halogen, C _1-4 -alkyl, C _1-4 -alkylthio, di-C _1-4 -alkylamino, halogen-C _1-4 -alkyl, halogen-C _{1 -4-} alkoxy, halo-C _1-4 -alkylthio, C _3-6 -cycloalkyl, halo-C _3-6 -cycloalkyl, nitro, cyano, amino, phenyl, halophenyl, phenoxy, phenylthio, halophenylthio substituted phenyl-, naphthyl -, pyridyl, benzofuryl, benzothienyl, quinolinyl, isoquinolinyl, oxazolyl, thiazolyl or pyrrolyl radical,
X is an oxygen or sulfur atom and
R₁ the residues -CF₂Br, -CH₂-CF₃, -CF₂-CCl₃, -CHF-CF₃, -CF₂-CFCl₂, -CF₂-CF₂Br, -CF₂-OCH₃, -CH₂-CF₂-CF₂H, -CH₂-CH₂F,

mean,
have a surprisingly good nematicidal effect with good plant tolerance.

The compounds of the invention also show a good one Effect against biting and sucking insects as well as against insect eggs and against mites.

The compounds of formula I according to the invention can be per se known methods by preparing compounds of formula II

where X and Ar have the meaning given in formula I, with compounds of the formula Z-R₁, where Z is an escape group such as. B. halogen, mesylate and Is tosylate and R₁ has the meaning given in formula I, in one inert solvent or solvent mixture, if necessary increased Temperature and optionally at elevated pressure in the presence of a base implements.

If R₁ is -CHF-CF₃, the compounds of formula II with 2,2,3-trifluoro-3-trifluoromethyloxirane in an inert solvent or solvent mixture at an optionally elevated temperature and, if appropriate implemented under increased pressure, the reaction being carried out in the presence a base runs.  

If R₁ the residues

mean, will Compounds of formula II with 2,2,3-trifluoro-3-trifluoromethyloxirane, in Methanol or ethanol as solvent and reactant, at temperatures implemented from -70 ° C to -40 ° C.

Organic and inorganic bases can be used as bases, such as e.g. B. tertiary amines such as triethylamine and tripropylamine, alkali and earth alkali metal hydrides, hydroxides, carbonates and bicarbonates, but also Alkaline alcoholates, such as. B. sodium methylate or potassium tert-butoxide.

Solvents suitable for the preparation of the compounds according to the invention are z. As diethyl ether, dioxane and tetrahydrofuran, aliphatic and aromatic hydrocarbons such as toluene and petroleum ether; halogenated Hydrocarbons such as chlorobenzene, methylene chloride, carbon tetrachloride, Chloroform; Nitriles such as acetonitrile, propionitrile; N, N-dialkylated amides such as dimethylformamide; Ketones such as acetone, methyl ethyl ketone; Dimethyl sulfoxide, Sulfolan as well as water and alcohols, e.g. B. methanol, ethanol, isopropanol or butanol and the mixtures of such solvents with one another.

As a catalyst comes z. B. 18-crown-6, 15-crown-5 or a tetraalkyl ammonium salt, such as tetra-n-butylammonium bromide.

The reaction is dependent on the reactants at temperatures performed between -70 ° C to 120 ° C. Also depending on the Reactants may be expedient to apply pressure. The one then applied Pressure is in the range between 1 to 25 bar. The response time is about 0.5 to 48 hours. The reaction mixture is then on Poured ice / water, extracted and worked up in a manner known per se. The products obtained can be recrystallized, Clean vacuum distillation or column chromatography.  

The compounds of formula II used as starting materials are partially known or can be prepared by methods known per se.

The 2-mercapto-1,3,4-oxadiozoles of the formula II are obtained, for example by adding carbon disulfide to a solution of the corresponding substituted hydrazide in alcoholic aqueous potassium hydroxide solution and Heating the reaction mixture for a few hours. The 2-mercapto 1,3,4-thiadiazoles of the formula II are obtained, for example, by treatment of the correspondingly substituted potassium dithiocarbazate with concentrated Sulfuric acid at -5 ° C to 10 ° C.

Due to the nematicidal activity with good plant tolerance can the compounds of the invention with success in crop protection as Pesticides in agriculture, wine, fruit and Horticulture and forestry are used.

The plant-parasitic nematodes which are controlled according to the invention can include, for example, the root gall nematodes, such as Meloidogyne incognita, Meloidogyne hapla, Meloidogyne javanica, the cysts forming Nematodes such as Globodera rostochiensis, Heterodera schachtii, Heterodera avenae, Heterodera glycines, Heterodera trifolii, stick and leaf whale, such as Ditylenchus dipsaci, Ditylenchus destructor, Aphelenchoides ritzemabosi, Pratylenchus neglectus, Pratylenchus penetrans, Pratylenchus curvitatus and Tylenchorhynchus dubius, Tylenchorhynchus claytoni, Rotylenchus robustus, Heliocotylenchus multicinctus, Radopholus similis, Belonolaimus longicaudatus, Longidorus elongatus and Trichodorus primitive.

Because of the insecticidal and acaricidal properties of the invention Connections, they also offer applications in the treatment of pests in various stages of Cultivated plants as well as pests on humans and animals.  

The active compounds according to the invention are used in the form of their commercial formulations and / or prepared from these formulations Application forms.

The active substance content of those prepared from the commercially available formulations Application forms can vary widely. The application rate for the control of nematodes per hectare is about 0.03 kg to about 10 kg, preferably about 0.3 kg to about 6 kg.

The active ingredients or their mixtures can be in the usual formulations are transferred like solutions, emulsions, wettable powders, suspensions, Powders, dusts, foams, pastes, soluble powders, granules, Aerosols, suspension emulsion concentrates, seed powder, active ingredient impregnated Natural and synthetic substances, very fine encapsulation in polymers Substances and in coating compositions for seeds, also in formulations with fuel sets, such as smoking cartridges, cans, spirals and. Ä. as well as ULV cold and Warm fog formulations.

These formulations are prepared in a known manner, e.g. B. by mixing the active ingredients with extenders, i.e. liquid solvents, pressurized liquefied gases and / or solid carriers, optionally using surface-active agents, that is to say emulsifiers and / or dispersing agents and / or foaming agents.

In the case of the use of water as an extender, e.g. Belly organic solvents can be used as auxiliary solvents.

Essentially aromatic liquid solvents are suitable Hydrocarbons such as xylene, toluene or alkylnaphthalenes, chlorinated Aromatics or chlorinated aliphatic hydrocarbons such as chlorobenzenes, Chlorethylene or methylene chloride, aliphatic hydrocarbons such as Cyclohexane or paraffins, e.g. B. petroleum fractions, alcohols such as butanol, Glycol and their ethers and esters, ketones such as acetone, methyl ethyl ketone, Methyl isobutyl ketone or cyclohexanone, strongly polar solvents such as Di methylformamide and dimethyl sulfoxide and water.  

With liquefied gaseous extenders or carriers are such Liquids are meant, which at normal temperature and under normal pressure are gaseous, e.g. B. aerosol propellants such as halogenated hydrocarbons and Butane, propane, nitrogen and carbon dioxide.

Solid rock powder such as kaolins, Clay, talc, chalk, quartz, attapulgite, montmorillonite or diatomaceous earth and synthetic rock flours such as highly disperse silica, Aluminum oxide and silicates as well as solid carriers for granules broken and fractionated natural rocks such as calcite, marble, pumice, Sepiolite, dolomite and synthetic granules from inorganic and organic Flours and granules from organic material such as sawdust, Coconut shells, corn cobs and tobacco stalks.

Non-ionic agents may be mentioned as emulsifiers or foam-generating agents and anionic emulsifiers such as polyoxyethylene fatty acid esters, polyoxy ethylene-fatty alcohol ether, e.g. B. alkylaryl polyglycol ethers, alkyl sulfonates, Aryl sulfonates and protein hydrolyzates.

As a dispersant such. B. lignin, sulfite and methyl cellulose called.

In the formulations, it is also possible to use adhesives such as carboxymethyl cellulose, natural and synthetic powdery, granular or latex-shaped polymers are used like gum arabic, polyvinyl alcohol and polyvinyl acetate.

Dyes such as inorganic pigments, e.g. B. iron dioxide, Titanium oxide, ferrocyan blue and organic dyes such as alizarin, azo Metal phthalocyanine dyes and trace nutrients such as salts of iron, Manganese, boron, copper, cobalt, molybdenum and zinc can also be used.

The formulations generally contain between 0.1 and 95 percent by weight Active ingredient, preferably between 0.5 and 90%.  

Examples of formulations are:

I. wettable powder

10 parts by weight of the compound according to Example 1 are mixed with 12 parts by weight Calcium salt of lignin sulfonic acid, 76 parts by weight Kaolin and 2 parts by weight of dialkylnaphthalenesulfonate intimately mixed and grind.

II. Dust powder

2.5 parts by weight of the compound according to Example 2 are in 10 parts Dissolved methylene chloride and on a mixture of 25 parts by weight powdered silica and 71.5 parts by weight of talc and 1 part by weight Given Sudan red. The solvent is removed in vacuo and the residue is finely ground.

III. granules

5 parts by weight of the compound according to Example 1 are in 10 parts Dissolved methylene chloride and granulated attapulgite to 95 parts by weight the grain size 0.3-0.8 mm sprayed and dried.

Emulsion concentrate

20 parts by weight of the compound according to Example 4 are in one Mixture of 75 parts by weight of isophorone and 5 parts by weight of one Mixture of 30 parts of phenyl sulfonate calcium salt, 30 parts Castor polyglycolate with 40 mol% ethylene oxide and 40 parts of one Copolymers of propylene and ethylene oxide dissolved.  

The following examples describe the preparation of the invention Links.

example 1 2-bromodifluoromethylthio-5- (4-chlorophenyl) -1,3,4-oxadiazole

1.5 (0.05 mol) of an 80% sodium hydride suspension in paraffin oil are washed once with 10 ml of toluene and suspended in 50 ml of dimethylformamide. A solution of 10.0 g (0.047 mol) of 5- (4-chlorophenyl) -1,3,4-oxadiazol-2-thiol in 50 ml of dimethylformamide is added dropwise at a temperature of 20-30 ° C. The mixture is stirred at room temperature for 30 minutes. Then 10.5 g (0.05 mol) of dibromodifluoromethane are added dropwise and the reaction mixture is stirred for 12 hours at room temperature. The reaction mixture is poured onto 300 ml of ice / water and extracted three times with 100 ml of ethyl acetate. The combined organic phases are dried over magnesium sulfate and concentrated. The purification is carried out by column chromatography (eluent: hexane / ethyl acetate 4: 1).
Yield: 4.30 g 26.8% of theory.
Mp .: 73 ° C.

Example 2 2- (4-chlorophenyl) -5- (1,2,2,2-tetrafluoroethylthio) -1,3,4-oxadiazole

60 ml of dimethylformamide and 6.38 g (0.03 mol) of 5- (4-chlorophenyl) -1,3,4-oxadiazol-2-thiol are stirred in an autoclave with 0.3 g of potassium hydroxide powder. 9.0 g (0.054 mol) of 2,2,3-trifluoro-3-trifluoromethyloxirane are pressed in and the reaction mixture is heated to 60-90 ° C. for 24 hours. After cooling and relieving the pressure, the solution is poured onto 300 ml of ice / water and extracted 3 times with 100 ml of ethyl acetate. The combined organic phases are dried over magnesium sulfate and concentrated. The purification is carried out by column chromatography (eluent: hexane / ethyl acetate 4: 1).
Yield: 2.0 g 21.3% of theory.
Mp .: 51 ° C.

Example 3 2- [5- (4-chlorophenyl) -1,3,4-thiadiazol-2-ylthiol] -2,3,3,3-tetrafluoro methyl propionate

9.15 g (0.04 mol) of 5- (4-chlorophenyl) -1,3,4-thiadiazol-2-thiol are dissolved in 100 ml of methanol and 0.95 g (0.04 mol) of sodium are added at room temperature . 2,2,3-trifluoro-3-trifluoromethyloxirane is introduced at a temperature of -50 ° C. and stirring is continued for 4.5 hours. The reaction solution is poured onto 300 ml of ice / water and extracted three times with 100 ml of ethyl acetate. The purification is carried out by column chromatography (eluent: hexane / ethyl acetate 4: 1).
Yield: 2.8 g 18% of theory.
Mp .: 50 ° C.

Example 4 2- (4-chlorophenyl) -5- (2,2,2-trifluoroethylthio) -1,3,4-oxadiazole

6.38 g (0.03 mol) of 5- (4-chlorophenyl-1,3,4-oxadiazol-2-thiol) are dissolved in 30 ml of dimethylformamide and the solution with 6.4 g (0.025 mol) of 2.2. 2-Tri fluoroethyl tosylate and 3.7 g (0.033 mol) of potassium tert-butoxide are added, and the reaction mixture is stirred for 12 h at about 100 ° C. The reaction solution is poured onto 250 ml of ice / water and three times with 100 ml of ethyl acetate The combined organic phases are dried over magnesium sulfate and concentrated, and the purification is carried out by column chromatography (eluent: hexane / ethyl acetate 4: 1).
Yield: 1.0 g 11.3% of theory.
Mp .: 90 ° C.

The following compounds are prepared in an analogous manner, the Substituents Ar, X and R₁ have the meanings given in formula I.

The following application examples show the biological effects of compounds of the invention.

Example of use A Control of root-bile nematodes (Meloidogyne incognita)

10% powdered active ingredient preparations are evenly mixed with the soil mixed, which is heavily contaminated with the test nematodes. Then you fill up the soil treated in this way in 0.5 liter clay bowls, seeds cucumber seeds and cultivates at a soil temperature of 25-27 ° C in the greenhouse. After a culture period of 25-28 days, the cucumber roots are washed out, in a water bath for nematode infestation (root galls) and the Efficiency of the active ingredient compared to the contaminated control in% certainly. If the nematode infestation is completely avoided, the efficiency is reduced set as 100%.

At a dose of 25 mg of active ingredient per liter of soil, nematode infestation could occur by Meloidogyne incognita by the compound according to Example 1 be completely (100%) avoided.

Example of use B Effect of curative leaf treatment of the bush bean (Phaseolus vulgaris nanus Aschers.) Against mobile stages of the common bean spider mite (Tetranychus urticae Koch)

In the warm greenhouse, seedlings of the broad bean are grown to full Development of the primary leaves attracted and then covered with leaf pieces, which are affected by Tetranychus urticae. A day later they will Leaf pieces removed and the plants containing a 0.1% active ingredient aqueous preparation sprayed to runoff. After 7 days at 22-24 ° C the proportion of dead mobile stages of Tetranychus in the treated and determined on untreated plants. According to Abbott, this becomes the effect of Treatment calculated.

The compound according to Example No. 1 had a more than 80% effect.  

Example of use C Effect of curative leaf treatment of the bush bean (Phaseolus vulgaris nanus Aschers.) Against common spider mite eggs (Tetranychus urticae Cook)

In the warm greenhouse, seedlings of the bush bean are grown until complete Development of the primary leaves attracted and then with adult females of Tetranychus urticae occupied. A day later the plants are planted with in the meantime laid eggs with aqueous preparation containing 0.1% active ingredient sprayed soaking wet. After 7 days at 22-24 ° C the percentage dead eggs determined on treated and untreated plants.

The compound according to Example 1 had more than 80% activity.

Example of use D Effect of prophylactic leaf treatment against the brown rice leafhopper (Nilaparvata lugens Stl)

Rice seedlings (about 15 per pot) are grown in the warm greenhouse until training The third leaf is tightened and then with a 0.1% active ingredient containing aqueous preparation sprayed to runoff. After drying a transparent cylinder is placed over the pot of the spray pads. On about 30 individuals of the brown rice leafhopper (Nilaparvata lugens) brought. After 2 days at 26 ° C in a greenhouse the percentage of cicadas killed is determined. With reference to some according to Abott, control pots that remain untreated become the effect calculated.

The compound according to Example 1 had an 80-100% effect.  

Application example E Killing effect on eggs / larvae of the corn rootworm (Diabrotica undecimpunctata)

The compounds of the invention are used as aqueous emulsions with the Active ingredient concentration 0.1% used. With these drug preparations the floors of polystyrene petri dishes and the corn seedlings contained therein (1 corn seedling / husk) and approx. 50 eggs of the corn rootworm (Diabrotica undecimpunctata) sprayed with 4 mg spray broth / cm². The sealed trays are kept at 25 ° C under long day conditions for 4 Days set up. The criterion for the impact assessment is the killing of eggs or the freshly hatching larvae at the end of the experiment.

The compound according to Example 1 showed an 80-100% effect.

Example of use F Ovicidal effect on egg clutches of the Egyptian cottonworm (Spodoptera littoralis Boisd.)

The compounds of the invention are used as aqueous suspensions or Emulsions with the active ingredient concentration 0.1% used. In this active ingredient Preparations are made from egg day eggs from fertilized female butterflies had been deposited on filter paper until completely wetted dipped and closed for 4 days in the laboratory under long day conditions Petri dishes deposited. Criterion for the impact assessment is the percentage slip prevention compared to untreated egg layers.

The compound according to Preparation Example 1 showed an 80-100% mortality effect.

Claims (5)

1. 2-Substituted 1,3,4-oxadiazole or 1,3,4-thiadiazole derivatives of the general formula I wherein
Ar is optionally one or more, the same or different, halogen, C _1-4 alkyl, C _1-4 alkylthio, di-C _1-4 alkylamino, halogen C _1-4 alkyl, halogen C _{1 -4-} alkoxy, halo-C _1-4 -alkylthio, C _3-6 - cycloalkyl, halo-C _3-6 -cycloalkyl, nitro, cyano, amino, phenyl, halophenyl, phenoxy, phenylthio, halophenylthio substituted phenyl-, naphthyl -, pyridyl, benzofuryl, benzothienyl, quinolinyl, isoquinolinyl, oxazolyl, thiazolyl or pyrrolyl radical,
X is an oxygen or sulfur atom and
R₁ the residues -CF₂Br, -CH₂-CF₃, -CF₂-CCl₃, -CHF-CF₃, -CF₂-CFCl₂, -CF₂-CF₂Br, -CF₂-OCH₃, -CH₂-CF₂-CF₂H, -CH₂-CH₂F, mean. 2. A process for the preparation of compounds of formula I, characterized in that compounds of formula II where X and Ar have the meaning given in formula I, with compounds of the formula Z-R₁, where Z is a leaving group from the group halogen, mesylate and tosylate, and R₁ has the meaning given in formula I, in an inert solvent or solvent mixture if appropriate at elevated temperature and if appropriate at elevated pressure in the presence of a base. 3. Use of compounds according to claim 1 of formula I for combating of pests, especially nematodes. 4. Pesticides characterized by a content of at least a compound according to claim 1 of formula I. 5. pesticide according to claim 4 in admixture with carrier and / or auxiliary substances.