DE3820628A1 - 5-Phenyl-1,3,4-oxa(thia)diazoles, their preparation and their use as pesticides - Google Patents

Abstract

There are described novel 5-phenyl-1,3,4-oxadiazole- or -1,3,4-thiadiazole derivatives of the general formula I <IMAGE> in which R1 represents a fluoro-C1-12-alkyl, fluoro-C2-12-alkenyl, fluoro-C2-12-alkynyl radical or the fluorocyclopropyl or fluorocyclopropylmethyl radical, R2 represents a hydrogen atom, a C1-12-alkyl, C2-12-alkenyl, C2-12-alkynyl, C3-6-cycloalkyl or C3-6-cycloalkylmethyl radical, each of which is optionally monosubstituted or polysubstituted by identical or different substituents from the series comprising halogen, C1-4-alkoxy, C1-4-alkylthio, C3-6-cycloalkyl, di-C1-4-alkylamino, halo-C1-4-alkoxy, halo-C1-4-alkylthio, halo-C3-6-cycloalkyl, C1-4-alkoxycarbonyl or halo-C1-4-alkoxycarbonyl R3 represents hydrogen, halogen, C1-6-alkyl, C1-6-alkoxy, C1-6-alkylthio, di-C1-6-alkylamino, halo-C1-6-alkyl, halo-C1-6-alkoxy, halo-C1-6-alkylthio, C1-6-alkoxycarbonyl, halo-C1-6-alkoxycarbonyl, nitro, cyano, amino, phenoxy, halophenoxy, phenylthio or halophenylthio and X and Y represent oxygen or sulphur, process for their preparation and their use as pesticides, in particular against nematodes.

Description

The invention relates to new 5-phenyl-1,3,4-oxadiazole- or 1,3,4-thiadiazole- Derivatives, their production and their use as pesticides, especially against nematodes.

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

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 5-phenyl-1,3,4-oxadiazole- or 1,3,4-thiadiazole- Derivatives of the general formula I

wherein
R₁ is a fluoro-C _1-12 -alkyl-, fluoro-C _2-12 -alkenyl-, fluoro-C _2-12 -alkynyl-, the fluorocyclopropyl or the fluorocyclopropylmethyl radical,
R₂ is a hydrogen atom, optionally one or more identical or different by halogen, C _1-4 alkoxy, C _1-4 alkylthio, C _3-6 - cycloalkyl, di-C _1-4 alkylamino, halogen-C _{1 -4-} alkoxy, halo-C _1-4 -alkylthio, halo-C _3-6 -cycloalkyl, C _1-4 -alkoxycarbonyl, halo-C _1-4 - alkoxycarbonyl-substituted C _1-12 -alkyl-, C _{2- 12} alkenyl, C _2-12 alkynyl, C _3-6 cycloalkyl or C _3-6 cycloalkylmethyl,
R₃ is hydrogen, halogen, C _1-6 alkyl, C _1-6 alkoxy, C _1-6 alkylthio, di-C _1-6 alkylamino, halo C _1-6 alkyl, halogen C _1-6 -alkoxy, halogen-C _1-6 -alkylthio, C _1-6 -alkoxycarbonyl, halogen-C _1-6 -alkoxycarbonyl, nitro, cyano, amino, phenoxy, halophenoxy, phenylthio or halophenylthio and
X and Y represent oxygen or sulfur,
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 term "haloalkyl" means that one or more hydrogen atoms of the alkyl radical are replaced by halogen. So the name says Fluoroalkyl, fluoroalkenyl, fluoroalkynyl, fluorocyclopropyl and fluorocyclopropylmethyl, that one or more hydrogen atoms of the alkyl or alkenyl or alkynyl or cyclopropyl radical are replaced by fluorine.

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

wherein R₁, R₃ and Y have the meaning given in formula I, with carbon disulfide in alcoholic-aqueous alkali hydroxide solution in the warm if X = oxygen or with concentrated sulfuric acid obtained with carbon disulphide and non-aqueous alkali hydroxide solution Reacts dithiocarbazate at temperatures below room temperature if X = Is sulfur, and optionally the 2-mercaptol compound thus obtained of formula III  

where R₁, R₃ and X have the meaning given in formula I, with compounds of the formula Z-R₂, where Z is an escape group such as. B. halogen, mesylate and is tosylate and R₂ has the meaning given in formula I, and if R₂ represents the radical -CHF-CF₃, with 2,2,3-trifluoro-3-trifluoromethyloxirane in an inert solvent or solvent mixture if appropriate elevated temperature and optionally at elevated pressure in the presence a base.

Organic and inorganic bases can be used as bases, such as e.g. B. tertiary amines such as triethylamine and tripropylamine, alkali and alkaline earth 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 tetraalkylammonium salt, such as tetra-n-butylammonium bromide, in question.

The reaction of the 2-mercaptols of the formula III to give compounds of the formula I. is dependent on the reactants at temperatures between room temperature up to 120 ° C, preferably at temperatures above room temperature, carried out. The application can also depend on the reactants be expedient of pressure. The pressure then applied is in the range between  1 to 25 bar. The reaction time is approximately 0.5 to 48 hours. The The reaction mixture is then poured onto ice water, extracted and worked up in a manner known per se. Leave the resulting products themselves in the usual way by recrystallization, vacuum distillation or Clean column chromatography.

The compounds of formula II used as starting materials are partially known or can be made analogously by known methods produce.

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 commercially available ones 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 polymer substances and in coating compositions for seeds, also in formulations with fuel sets, such as smoking cartridges, cans, spirals and. as well as ULV cold and warm fog Wording.

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.

Aromatic hydrocarbons are essentially suitable as liquid solvents 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 as well as their ethers and esters, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone, strongly polar solvents such as dimethylformamide 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 materials 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, polyoxyethylene Fatty alcohol ethers, e.g. B. alkylaryl polyglycol ethers, alkyl sulfonates, Aryl sulfonates and protein hydrolyzates.

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

Auxiliaries 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 1.1 are intimately mixed and ground with 12 parts by weight of calcium salt of lignosulfonic acid, 76 parts by weight of kaolin and 2 parts by weight of dialkylnaphthalenesulfonate.
• II. Dust powder:
  2.5 parts by weight of the compound according to Example 2.1 are dissolved in 10 parts of methylene chloride and added to a mixture of 25 parts by weight of powdered silica and 71.5 parts by weight of talc and 1 part by weight of 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 1.1 are dissolved in 10 parts of methylene chloride and sprayed onto 95 parts by weight of granulated attapulgite with a particle size of 0.3-0.8 mm and dried.
• IV. Emulsion concentrate:
  20 parts by weight of the compound according to Example 1.1 are dissolved in a mixture of 75 parts by weight of isophorone and 5 parts by weight of a mixture of 30 parts of phenylsulfonate calcium salt, 30 parts of castor polyglycolate with 40 mol% of ethylene oxide and 40 parts of a copolymer of propylene and ethylene oxide.

The following examples describe the preparation of the invention Links.

Example 1.1 5- (4-difluoromethoxyphenyl) -1,3,4-oxadiazol-2-thiol

14.0 g (0.069 mol) of 4-difluoromethoxybenzhydrazide are dissolved in 300 ml of ethanol dissolved and with 3.87 g (0.069 mol) of potassium hydroxide, dissolved in 17 ml of water, transferred. At room temperature, 7.6 g (0.10 mol) of carbon disulfide are added with stirring dripped. The reaction mixture is then 7 hours Reflux cooked. The reaction mixture is then evaporated to dryness, the residue was taken up in about 500 ml of water and filtered. The clear solution is adjusted to pH = 2 with concentrated hydrochloric acid. The resulting crystals are suctioned off and twice with Washed water.

Yield: 14.1 g 83.7% of theory.
Mp: 155-157 ° C.

Example 1.2 5- (4-difluoromethoxyphenyl) -1,3,4-thiadiazole-2-thiol

9.7 g (0.031 mol) of 4-difluoromethoxybenzoyl potassium dithiocarbazate are dissolved in 45 ml of concentrated sulfuric acid were added in portions at 5 ° C. The The mixture is stirred at 0 ° C for 30 minutes. Then the reaction solution added to 300 ml of ice water and the resulting precipitate is suction filtered. The precipitate is washed 3 times with water.

Yield: 6.9 g 85.5% of theory.
Mp .: 178-179 ° C.

The following compounds of the formula I are prepared analogously, where R₂ = H is.

Example 2.1 5- (4-difluoromethoxyphenyl) -2-difluoromethylthio-1,3,4-thiadiazole

10.0 g (0.038 mol) of 5- (4-difluoromethoxyphenyl) -1,3,4-thiadiazole-2-thiol are dissolved or suspended in 50 ml of dioxane and with vigorous stirring 31 g of a 34% potassium hydroxide solution were added dropwise. The reaction mixture is heated to 60 ° to 70 ° C and with good stirring for 3 hours weak stream of chlorodifluoromethane initiated. Then that will The reaction mixture was poured onto 300 ml of ice water and 3 times with 100 ml of ethyl acetate extracted. The combined organic phases are over magnesium sulfate dried and concentrated. The purification is carried out using column chromatography (Eluent: hexane / ethyl acetate 4: 1).

Yield: 2.83 g 22.8% of theory.
n : 1.5754.

The following compounds of the formula I prepared, where R² ≠ H.

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 through the compounds according to the examples 2.1 and 2.2 should be avoided completely (100%).

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 bush bean are grown until complete 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 2.1 had an activity of more than 80%.  

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 effect of the treatment is calculated from this according to Abbott.

The compound according to Example 2.1 had an activity of more than 80%.

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

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 Abbott, control pots that remain untreated become the effect calculated.

The compound according to Example 2.2 had a 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 compounds according to Examples 2.1 and 2.2 showed more than 80% 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 these drug preparations are 1-day-old egg clutches made by 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. The criterion for the impact assessment is the percentage slip prevention compared to untreated egg layers.

The compound according to Examples 2.1 and 2.2 showed a more than 80% mortality effect.

Claims (5)

1. 5-phenyl-1,3,4-oxadiazole or 1,3,4-thiadiazole derivatives of the general formula I wherein
R₁ is a fluoro-C _1-12 -alkyl-, fluoro-C _2-12 -alkenyl-, fluoro-C _2-12 -alkynyl-, the fluorocyclopropyl or the fluorocyclopropylmethyl radical,
R₂ is a hydrogen atom, optionally one or more identical or different by halogen, C _1-4 alkoxy, C _1-4 alkylthio, C _3-6 - cycloalkyl, di-C _1-4 alkylamino, halogen-C _{1 -4-} alkoxy, halo-C _1-4 -alkylthio, halo-C _3-6 -cycloalkyl, C _1-4 -alkoxycarbonyl, halo-C _1-4 - alkoxycarbonyl-substituted C _1-12 -alkyl-, C _{2- 12} alkenyl, C _2-12 alkynyl, C _3-6 cycloalkyl or C _3-6 cycloalkylmethyl,
R₃ is hydrogen, halogen, C _1-6 alkyl, C _1-6 alkoxy, C _1-6 alkylthio, di-C _1-6 alkylamino, halo C _1-6 alkyl, halogen C _1-6 -alkoxy, halogen-C _1-6 -alkylthio, C _1-6 -alkoxycarbonyl, halogen-C _1-6 -alkoxycarbonyl, nitro, cyano, amino, phenoxy, halophenoxy, phenylthio or halophenylthio and
X and Y represent oxygen or sulfur. 2. A process for the preparation of compounds of formula I, characterized in that compounds of formula II wherein R₁, R₃ and Y have the meaning given in formula I, with carbon disulfide in alcoholic aqueous alkali hydroxide solution in the heat, if X = oxygen or with concentrated sulfuric acid, the dithiocarbazate obtained with carbon disulfide and non-aqueous alkali hydroxide solution at temperatures below Reacts room temperature if X = sulfur, and optionally the 4-mercaptol compound of formula III thus obtained where R₁, R₃ and X have the meaning given in formula I, with compounds of the formula Z-R₂, where Z is an escape group such as. B. is halogen, mesylate and tosylate and R₂ has the meaning given in formula I, and if R₂ is the radical -CHF-CF₃, with 2,2,3-trifluoro-3-trifluoromethyloxirane in an inert solvent or solvent mixture, optionally increased Temperature and optionally 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. pesticide, 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.