5-Phenoxyphenyl-tetrahydro-1,3,5-thiadiazin-4-ones

Abstract

The invention relates to novel substituted 5-phenoxyphenyl-tetrahydro-1,3,5-thiadiazin-4-ones of the formula ##STR1## wherein R.sub.1 is hydrogen, halogen, C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, methoxy, ethoxy, benzyl, phenoxy, phenylthio, or phenoxy or phenylthio substituted by a radical selected from the group consisting of halogen, C.sub.1 -C.sub.4 -alkyl, methoxy and ethoxy; each of R.sub.2 and R.sub.3 independently of the other is hydrogen, halogen, C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, methoxy or ethoxy; each of R.sub.4 and R.sub.5 independently of the other is hydrogen or C.sub.1 -C.sub.6 -alkyl; and each of R.sub.6 and R.sub.7 independently of the other is C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, C.sub.3 -C.sub.6 -cycloalkyl, alkoxyalkyl containing a total of 2 to 6 carbon atoms, benzyl, phenyl or phenyl which is substituted by a member selected from the group consisting of halogen, C.sub.1 -C.sub.4 -alkyl, methoxy and ethoxy, to the preparation of these novel compounds and to compositions containing them for use in pest control, especially for controlling insects and representatives of the order Acarina which are pests of plants and animals. The novel compounds are particularly effective against larval stages and nymphs of plant-destructive feeding insects, and most particularly against plant destructive cicadas, especially in rice crops.

Description

The present invention relates to novel substituted 5-phenoxyphenyl-tetrahydro-1,3,5-thiadiazin-4-ones, to the preparation thereof and to the use thereof in pest control.

The novel compounds of this invention have the formula ##STR2## wherein R.sub.1 is hydrogen, halogen, C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, methoxy, ethoxy, benzyl, phenoxy, phenylthio, or phenoxy or phenylthio substituted by a radical selected from the group consisting of halogen, C.sub.1 -C.sub.4 -alkyl, methoxy and ethoxy; each of R.sub.2 and R.sub.3 independently of the other is hydrogen, halogen, C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, methoxy or ethoxy; each of R.sub.4 and R.sub.5 independently of the other is hydrogen or C.sub.1 -C.sub.6 -alkyl; and each of R.sub.6 and R.sub.7 independently of the other is C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, C.sub.3 -C.sub.6 -cycloalkyl, alkoxyalkyl containing a total of 2 to 6 carbon atoms, benzyl, phenyl or phenyl which is substituted by a member selected from the group consisting of halogen, C.sub.1 -C.sub.4 -alkyl, methoxy and ethoxy.

Particularly interesting compounds of this invention are compounds of the formula Ia, ##STR3## wherein R.sub.1 to R.sub.7 are as defined for formula I.

Compounds meriting special interest are also compounds of the formula I or Ia, wherein R.sub.1 is hydrogen, halogen, C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, methoxy, benzyl or phenoxy; each of R.sub.2 and R.sub.3 independently of the other is hydrogen, halogen or C.sub.1 -C.sub.4 -alkyl; each of R.sub.4 and R.sub.5 independently of the other is hydrogen or C.sub.1 -C.sub.4 -alkyl; and each of R.sub.6 and R.sub.7 independently of the other is C.sub.1 -C.sub.4 -alkyl, C.sub.3 -C.sub.6 -cycloalkyl, alkoxyalkyl containing a total of 2 to 4 carbon atoms, phenyl or phenyl which is substituted by a member selected from the group consisting of halogen and C.sub.1 -C.sub.4 -alkyl.

Particularly preferred compounds of the formula Ia are those wherein R.sub.1 is hydrogen, chlorine, methyl, trifluoromethyl, methoxy, benzyl or phenoxy; R.sub.2 is hydrogen, chlorine or methyl; R.sub.3 is hydrogen; each of R.sub.4 and R.sub.5 independently of the other is hydrogen or C.sub.1 -C.sub.4 -alkyl; and each of R.sub.6 and R.sub.7 independently of the other is C.sub.1 -C.sub.4 -alkyl, cyclopropyl, phenyl or chlorophenyl.

On account of their pronounced pesticidal activity, the most preferred compounds of the formula Ia are those wherein R.sub.1 is methyl, trifluoromethyl or benzyl; R.sub.2 is hydrogen or methyl; R.sub.3 is hydrogen; each of R.sub.4 and R.sub.5 independently of the other is methyl or ethyl; and each of R.sub.6 and R.sub.7 independently of the other is C.sub.3 -C.sub.4 -alkyl.

The present invention also relates to the salts, especially to the salts which are tolerated by plants, of the compounds of the formulae I and Ia. Examples of such suitable salts with organic and inorganic acids are: chlorides, bromides, iodides, sulfates, hydrogensulfates, chlorates, perchlorates, thiocyanates, nitrates, phosphates, hydrogen phosphates, tetrafluoroborates, formates, acetates, trichloroacetates, trifluoroacetates, phenylsulfonates, oxalates, malonates, succinates, malates, tartrates or citrates.

The compounds of the formulae I and Ia, and the salts thereof, may be prepared in a manner which is known per se (q.v. German Offenlegungsschrift No. 28 24 126) by reacting a compound of the formula II ##STR4## with a compound of the formula III ##STR5## in which formulae R.sub.1 to R.sub.7 are as defined above and X is halogen, preferably chlorine.

This reaction is normally conducted in the presence of a base to give the free compound of the formula I. If the reaction is carried out without a base, then the corresponding salts, i.e. hydrohalides, are obtained. If required, such hydrohalides may be converted by known methods with other acids into salts of the desired kind. Suitable bases are inorganic bases such as KOH, NaOH, NH.sub.4 OH or NaCO.sub.3, as well as organic bases such as trialkylamines, e.g. triethylamine or ethyl diisopropylamine, pyridine, dialkyl anilines etc.

The reaction to give the compounds of the formula I is preferably carried out in a solvent. Examples of suitable solvents are aromatic hydrocarbons such as benzene, toluene and xylene; ketones such as acetone, cyclohexanone and methyl ethyl ketone; ethers such as tetrahydrofuran, dioxan and diethyl ether; halogenated hydrocarbons such as chloroform, carbon tetrachloride and chlorobenzene; alcohols such as ethanol and propanol; esters of aliphatic acids such as ethyl acetate; aliphatic amides such as dimethyl formamide and dimethyl acetamide; dimethyl sulfoxide and other solvents which do not influence the reaction. These solvents may also be employed as mixtures.

The reaction temperature may vary within wide limits from -10.degree. to +300.degree. C. The preferred temperature range is from room temperature to about 200.degree. C.

The starting phenoxy-N-halomethyl-N-phenylcarbamoyl halides of the formula II and thioureas of the formula III are known or may be obtained by methods analogous to known ones (q.v. German Offenlegungsschrift No. 28 24 126; J. Org. Chem. 39, 2897/1974; Chem. Abstr. 59,9816 ff). For example, a compound of the formula II may be obtained by reacting a phenoxyaniline of the formula IV with formaldehyde and then reacting the resultant phenoxy-N-methyleneaniline of the formula V with phosgene: ##STR6## Anilines of the formula IV and the preparation thereof are described e.g. in German Offenlegungsschrift No. 30 34 905.

It is already known from German Offenlegungsschrift No. 28 24 126 that 5-phenyl-tetrahydro-1,3,5-thiadiazin-4-ones which are substituted at the phenyl group by alkyl, nitro, halogen, alkoxy or trifluoromethyl, are pesticidally active, in particular against insects and mites. Compared with these known compounds, the compounds of the formula I of this invention are novel substituted 5-phenoxyphenyltetrahydro-1,3,5-thiadiazin-4-ones which, surprisingly, have a more potent, in particular pesticidal, activity. Surprising too is the very rapid action which the compounds of the formula I have in particular against representatives of the order Orthoptera.

In general, the compounds of the formula I are suitable for controlling insects of the orders: Lepidoptera, Coleoptera, Homoptera, Heteroptera, Diptera, Thysanoptera, Orthoptera, Blattaria, Anoplura, Siphonaptera, Mallophaga, Thysanura, Isoptera, Psocoptera and Hymenoptera.

The compounds of formula I are furthermore suitable for controlling representatives of the order Acarina of the families: Ioxididae, Argisidae, Tetranychidae and Dermanyssidae. The compounds of formula I may be employed with success in particular for controlling phytopathogenic mites, e.g. of the families Tetranychidae and Phytoptipalpidae (spider mites), Tarsonemidae (soft-bodied mites) and Eriophydiae (gall mites).

In addition to their action against mites and flies, e.g. Aedes aegypti and Musca domestica, the compounds of formula I are also suitable for controlling plant-destructive feeding insects on ornamentals and crops of useful plants, especially in cotton (e.g. against Spodoptera littoralis and Heliothis virescens) and in cereals, fruit and vegetables (e.g. against Laspeyresia pomonella, Leptinotarsa decemlineata and Epilachna varivestis). The compounds of formula I are also very effective against larval insect stages and nymphs, especially of harmful feeding insects. In particular, the compounds of formula I may be successfully employed against plant-destructive cicadas, especially in rice crops.

Furthermore, the compounds of formula I may be used for controlling ectoparasitic insects and acarids in domestic animals and productive livestock, e.g. by treating animals, cowsheds, barns, stables etc., and pastures.

The activity of the compounds of formula I and of the compositions containing them may be substantially broadened and adapted to prevailing circumstances by addition of other insecticides and/or acaricides. Examples of suitable additives are representatives of the following classes of compounds: organophosphorus compounds, nitrophenols and derivatives thereof, formamides, ureas, pyrethroids, carbamates, chlorinated hydrocarbons, and Bacillus thuringiensis preparations. Compounds of formula I may be combined with particular advantage with diazinon, dioxacarb, heptenophos and isoprocarb to obtain effective insecticidal compositions which are suitable in particular for controlling destructive insects in rice crops.

The good insecticidal activity of the compounds of the formula I and Ia and the salts thereof corresponds to a mortality of at least 50 to 60% of the pests mentioned above.

The compounds of the formula I, and accordingly also the salts thereof, are used in unmodified form or, preferably, together with the adjuvants conventionally employed in the art of formulation, and are therefore formulated in known manner to emulsifiable concentrates, directly sprayable or dilutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granulates, and also encapsulations in e.g. polymer substances. Like the nature of the compositions, the methods of application, such as spraying, atomising, dusting, scattering or pouring, are chosen in accordance with the intended objectives and the prevailing circumstances.

The formulations, i.e. the compositions containing the compound of the formula I or a combination thereof with other insecticides or acaricides, and, where appropriate, a solid or liquid adjuvant, are prepared in known manner, e.g. by homogeneously mixing and/or grinding the active ingredients with extenders, e.g. solvents, solid carriers and, where appropriate, surface-active compounds (surfactants).

Suitable solvents are: aromatic hydrocarbons, preferably the fractions containing 8 to 12 carbon atoms, e.g. xylene mixtures or substituted naphthalenes, phthalates such as dibutyl phthalate or dioctyl phthalate, aliphatic hydrocarbons such as cyclohexane or paraffins, alcohols and glycols and their ethers and esters, such as ethanol, ethylene glycol, ethylene glycol monomethyl or monoethyl ether, ketones such as cyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone, dimethyl sulfoxide or dimethyl formamide, as well as epoxidised vegetable oils such as epoxidised coconut oil or soybean oil; or water.

The solid carriers used e.g. for dusts and dispersible powders, are normally natural mineral fillers, such as calcite, talcum, kaolin, montmorillonite or attapulgite. In order to improve the physical properties it is also possible to add highly dispersed silicic acid or highly dispersed absorbent polymers. Suitable granulated adsorptive carriers are porous types, for example pumice, broken brick, sepiolite or bentonite; and suitable nonsorbent carriers are materials such as calcite or sand. In addition, a great number of pregranulated materials of inorganic or organic nature can be used, e.g. especially dolomite or pulverised plant residues.

Depending on the nature of the compound of the formula I to be formulated, or combination thereof with other insecticides or acaricides, suitable surface-active compounds are nonionic, cationic and/or anionic surfactants having good emulsifying, dispersing and wetting properties. The term "surfactants" will also be understood as comprising mixtures of surfactants.

Suitable anionic surfactants can be both water-soluble soaps and water-soluble synthetic surface-active compounds.

Suitable soaps are the alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts of higher fatty acids (C.sub.10 -C.sub.22), e.g. the sodium or potassium salts of oleic or stearic acid, or of natural fatty acid mixtures which can be obtained e.g. from coconut oil or tallow oil. Mention may also be made of fatty acid methyl taurin salts.

More frequently, however, so-called synthetic surfactants are used, especially fatty sulfonates, fatty sulfates, sulfonated benzimidazole derivatives of alkylarylsulfonates.

The fatty sulfonates or sulfates are usually in the form of alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts and contain a C.sub.8 -C.sub.22 alkyl radical which also includes the alkyl moiety of acyl radicals, e.g. the sodium or calcium salt of lignosulfonic acid, of dodecylsulfate or of a mixture of fatty alcohol sulfates obtained from natural fatty acids. These compounds also comprise the salts of sulfuric acid esters and sulfonic acids of fatty alcohol/ethylene oxide adducts. The sulfonated benzimidazole derivatives preferably contain 2 sulfonic acid groups and one fatty acid radical containing 8 to 22 carbon atoms. Examples of alkylarylsulfonates are the sodium, calcium or triethanolamine salts of dodecylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, or of a naphthalenesulfonic acid/formaldehyde condensation product. Also suitable are corresponding phosphates, e.g. salts of the phosphoric acid ester of an adduct of p-nonylphenol with 4 to 14 moles of ethylene oxide.

Non-ionic surfactants are preferably polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols, or saturated or unsaturated fatty acids and alkylphenols, said derivatives containing 3 to 30 glycol ether groups and 8 to 20 carbon atoms in the (aliphatic) hydrocarbon moiety and 6 to 18 carbon atoms in the alkyl moiety of the alkylphenols.

Further suitable non-ionic surfactants are the water-soluble adducts of polyethylene oxide with polypropylene glycol, ethylene-diaminepropylene glycol and alkylpolypropylene glycol containing 1 to 10 carbon atoms in the alkyl chain, which adducts contain 20 to 250 ethylene glycol ether groups and 10 to 100 propylene glycol ether groups. These compounds usually contain 1 to 5 ethylene glycol units per propylene glycol unit.

Representative examples of non-ionic surfactants are nonylphenol polyethoxyethanols, castor oils polyglycol ethers, polypropylene/polyoxyethylene adducts, tributylphenoxypolyethoxyethanol, polyethylene glycol and octylphenoxypolyethoxyethanol. Fatty acid esters of polyoxyethylene sorbitan and polyoxyethylene sorbitan trioleate are also suitable non-ionic surfactants.

Cationic surfactants are preferably quaternary ammonium salts which contain, as N-substituent, at least one C.sub.8 -C.sub.22 alkyl radical and, as further substituents, lower unsubstituted or halogenated alkyl, benzyl or lower hydroxyalkyl radicals. The salts are preferably in the form of halides, methyl sulfates or ethyl sulfates, e.g. stearyl trimethylammonium chloride or benzyl di-(2-chloroethyl)ethylammonium bromide.

The surfactants customarily employed in the art of formulation are described e.g. in "McCutcheon's Detergents and Emulsifiers Annual," MC Publishing Corp., Ringwood, N.J., 1979, and Sisely and Wood, "Encyclopedia of Surface Active Agents," Chemical Publishing Co., Inc. New York (1979).

The pesticidal formulations usually contain 0.1 to 99%, preferably 0.1 to 95%, of a compound of the formula I or combination thereof with other insecticides or acaricides, 1 to 99,9% of a solid or liquid adjuvant, and 0 to 25%, preferably 0.1 to 20%, of a surfactant.

Whereas commercial products are preferably formulated as concentrates, the end user will normally employ dilute formulations.

The formulations may also contain further additives such as stabilisers, antifoams, viscosity regulators, binders, tackifiers and fertilisers or other active ingredients in order to obtain special effects.

Formulation Examples for liquid active ingredients of the formula I or combinations thereof with other insecticides or acaricides (throughout, percentages are by weight)

______________________________________1. Emulsifiable concentrates (a) (b) (c)______________________________________active ingredient or active 25% 40% 50%ingredient combinationcalcium dodecylbenzenesulfonate 5% 8% 6%castor oil polyethylene glycol 5% -- --ether (36 moles of ethylene oxide)tributylphenol polyethylene glycol -- 12% 4%ether (30 moles of ethylene oxide)cyclohexane -- 15% 20%xylene mixture 65% 25% 20%______________________________________ Emulsion of any required concentration can be produced from such concentrates by dilution with water. ______________________________________2. Solutions (a) (b) (c) (d)______________________________________active ingredient or active 80% 10% 5% 95%ingredient combinationethylene glycol monomethyl ether 20% -- -- --polyethylene glycol 400 -- 70% -- --N--methyl-2-pyrrolidone -- 20% -- --expoxidised coconut oil -- -- 1% 5%ligroin (boiling range 160-190.degree.) -- -- 94% --______________________________________ These solutions are suitable for application in the form of microdrops. ______________________________________3. Granulates (a) (b)______________________________________active ingredient or active 5% 10%ingredient combinationkaolin 94% --highly dispersed silicic acid 1% --attapulgite -- 90%______________________________________ The active ingredient is dissolved in methylene chloride, the solution is sprayed onto the carrier, and the solvent is subsequently evaporated off in vacuo. ______________________________________4. Dusts (a) (b)______________________________________active ingredient or active 2% 5%ingredient combinationhighly dispersed silicic acid 1% 5%talcum 97% --kaolin -- 90%______________________________________ Ready for use dusts are obtained by intimately mixing the carriers with the active ingredient.

Formulation examples for solid active ingredients of the formula I or combinations thereof with other insecticides or acaricides (throughout, percentages are by weight)

______________________________________5. Wettable powders (a) (b) (c)______________________________________active ingredient or active 25% 50% 75%ingredient combinationsodium lignosulfonate 5% 5% --sodium laurylsulfate 3% -- 5%sodium diisobutylnaphthalene- -- 6% 10%sulfonateoctylphenol polyethylene glycol -- 2% --ether (7-8 moles of ethylene oxide)highly dispersed silicic acid 5% 10% 10%kaolin 62% 27% --______________________________________ The active ingredient is thoroughly mixed with the adjuvants and the mixture is thoroughly ground in a suitable mill, affording wettable powders which can be diluted with water to give suspensions of the desired concentration. ______________________________________6. Emulsifiable concentrate______________________________________active ingredient or active ingredient 10%combinationoctylphenol polyethylene glycol ether 3%(4-5 moles of ethylene oxide)calcium dodecylbenzenesulfonate 3%castor oil polyglycol ether 4%(36 moles of ethylene oxide)cyclohexanone 30%xylene mixture 50%______________________________________ Emulsions of any required concentration can be obtained from this concentrate by dilution with water. ______________________________________7. Dusts (a) (b)______________________________________active ingredient or active 5% 8%ingredient combinationtalcum 95% --kaolin -- 92%______________________________________ Ready for use dusts are obtained by mixing the active ingredient with the carriers, and grinding the mixture in a suitable mill. ______________________________________8. Extruder granulate______________________________________active ingredient or active 10%ingredient combinationsodium lignosulfonate 2%carboxymethylcellulose 1%kaolin 87%.______________________________________ The active ingredient is mixed and ground with the adjuvants, and the mixture is subsequently moistened with water. The mixture is extruded and then dried in a stream of air. ______________________________________9. Coated granulate______________________________________active ingredient or active 3%ingredient combinationpolyethylene glycol 200 3%kaolin 94%______________________________________ The finely ground active ingredient is uniformly applied, in a mixer, to the kaolin moistened with polyethylene glycol. Non-dusty coated granulates are obtained in this manner. ______________________________________10. Suspension concentrate______________________________________active ingredient or active 40%ingredient combinationethylene glycol 10%nonylphenol polyethylene glycol 6%ether (15 moles of ethylene oxide)sodium lignosulfonate 10%carboxymethylcellulose 1%37% aqueous formaldehyde solution 0.2%silicone oil in the form of a 75% 0.8%aqueous emulsionwater 32%.______________________________________ The finely ground active ingredient is intimately mixed with the adjuvants, giving a suspension concentrate from which suspensions of any desired concentration can be obtained by dilution with water.

PREPARATORY EXAMPLES

EXAMPLE 1

(a) Preparation of N-chloromethyl-N-[4-(p-benzylphenoxy)-2,6-dimethylphenyl]carbamoyl chloride (starting compound):

A mixture of 64,4 g (0.35 mole) of p-benzylphenol, 500 ml of xylene and 28 g (0,45 mole) of pulverised potassium hydroxide is heated for 4 hours under reflux. The water formed is removed from the reaction mixture. Then 60 g (0,3 mole) of 4-bromo-2,6-dimethylaniline and 1 g of CuCl are added and the xylene is distilled off under nitrogen until the temperature in the reaction mixture is 160.degree.-170.degree.. The reaction mixture is stirred at this temperature for 12 hours, allowed to cool to 70.degree.-80.degree. C., and then taken up in 500 ml of toluene and filtered. The filtrate is diluted with diethyl ether, washed twice with 10% potassium hydroxide solution and three times with saturated sodium chloride solution, dried over sodium sulfate and concentrated. The residue is purified over a column of silica gel with a 1:3 mixture of ethyl acetate/hexane as eluant. The eluant is evaporated off to give 4-(p-benzylphenoxy)-2,6-dimethylaniline as a dark liquid which after a time forms crystals with a melting point of 61.degree.-63.degree. C.

A mixture of 31.5 g (0.104 mole) of 4-(p-benzylphenoxy)-2,6-dimethylaniline, 120 ml of benzene, 3.3 g (0.11 mole) of granulated paraformaldehyde and 1 ml of triethylamine (as 25% solution in methanol) is heated for 5 hours under reflux. The water formed is removed from the reaction mixture. The residue consisting of 4-(p-benzylphenoxy)-2,6-dimethyl-N-methyleneaniline is concentrated, dried and dissolved in 100 ml of benzene. With stirring, 60 ml of a solution of phosgene (20% by volume) in toluene are addded dropwise to the above solution. The reaction mixture is stirred for 1 hour and then concentrated, leaving as residue N-chloromethyl-N-[4-(p-benzylphenoxy)-2,6-dimethylphenyl]carbamoyl chloride.

(b) Preparation of 2-tert-butylimino-3-isopropyl-5-(4-benzylphenoxy-2,6-dimethylphenyl)-tetrahydro-1,3,5-thiadiazin-4-one:

16,5 g (0.04 mole) of N-chloromethyl-N-[4-(p-benzylphenoxy)2,6-dimethylphenyl]carbamoyl chloride obtained in (a) are mixed with 60 ml of methylene chloride and 10.3 g (0.08 mole) of ethyl diisopropylamine. Then 6.9 g (0.04 mole) of N-tert-butyl-N'-isopropylthiourea in 50 ml of methylene chloride are added dropwise to the above mixture and the batch is heated for 48 hours under reflux. The cooled reaction mixture is then taken up in diethyl ether and the solution is washed twice with water and twice with saturated sodium chloride solution, dried over sodium sulfate and concentrated. The liquid residue is purified over a column of silica gel with a 1:3 mixture of ethyl acetate/hexane as eluant. The title compound (compound 1) is obtained in the form of a viscous oil whose structure is confirmed by its NMR structure:

NMR (CDCl.sub.3): 1.32 (s,9H); 1.45 (d,6H); 2.2 (s, 6,H); 3.91 (s, 2H); [in ppm] 4.45 (s. 2H); 4.5-5.0 (m,.about.1H); 6.5-7.1 (m, 11H).

After a time the viscous oil crystallises (m.p. 129.degree.-130.degree. C.). The following compounds of formula Ia are obtained in corresponding manner:

__________________________________________________________________________Compound R.sub.1 R.sub.2 R.sub.3 R.sub.4 R.sub.5 R.sub.6 R.sub.7 Physical__________________________________________________________________________ data2 H H H C.sub.2 H.sub.5 ##STR7## ##STR8## ##STR9## n.sub.D.sup.20 = 1.55873 CF.sub.3 H H CH.sub.3 CH.sub.3 ##STR10## ##STR11## n.sub.D.sup.20 = 1.54244 CF.sub.3 H H CH.sub.3 CH.sub.3 ##STR12## ##STR13## m.p. 103-105.degree. C.5 CH.sub.32-CH.sub.3 H CH.sub.3 CH.sub.3 ##STR14## ##STR15## m.p. 174-175.degree. C.6 CH.sub.32-CH.sub.3 H CH.sub.3 CH.sub.3 ##STR16## ##STR17## m.p. 179-180.degree. C.7 CH.sub.32-CH.sub.3 H C.sub.2 H.sub.5 C.sub.2 H.sub.5 ##STR18## ##STR19## n.sub.D.sup.20 = 1.56208 CH.sub.32-CH.sub.3 H C.sub.2 H.sub.5 C.sub.2 H.sub.5 ##STR20## ##STR21## n.sub.D.sup.20 1.5571 ##STR22## H H CH.sub.3 CH.sub.3 ##STR23## ##STR24## n.sub.D.sup.20 = 1.596910 ##STR25## H H CH.sub.3 CH.sub.3 ##STR26## ##STR27## m.p. 106-107.degree. C.11 H H H CH.sub.3 CH.sub.3 ##STR28## ##STR29## m.p. 98-100.degree. C.12 H H H CH.sub.3 CH.sub.3 ##STR30## ##STR31## m.p. 107.degree. C.13 H H H CH.sub.3 CH.sub.3 ##STR32## ##STR33## m.p. 138-139.degree. C.14 H H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR34## m.p. 148-150.degree. C.15 H H H CH.sub.3 CH.sub.3 ##STR35## ##STR36## m.p. 164-165.degree. C.16 H H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR37## m.p. 139-140.degree. C.17 ##STR38## H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR39## m.p. 144-145.degree. C.18 ##STR40## H H CH.sub.3 CH.sub.3 ##STR41## ##STR42## m.p. 150.degree. C.19 ##STR43## H H CH.sub.3 CH.sub.3 ##STR44## ##STR45## m.p. 179-180.degree. C.20 Cl H H CH.sub.3 CH.sub.3 ##STR46## ##STR47## m.p. 100-102.degree. C.21 Cl H H CH.sub.3 CH.sub.3 ##STR48## ##STR49## n.sub.D.sup.20 = 1.564322 Cl H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR50## m.p. 135-136.degree. C.23 Cl H H CH.sub.3 CH.sub.3 ##STR51## ##STR52## m.p. 167-168.degree. C.24 Cl H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR53## m.p. 163-164.degree. C.25 Cl H H CH.sub.3 CH.sub.3 ##STR54## ##STR55## m.p. 124-126.degree. C.26 CH.sub.3 H H CH.sub.3 CH.sub.3 ##STR56## ##STR57## m.p. 148-150.degree. C.27 CH.sub.3 H H CH.sub.3 CH.sub.3 ##STR58## ##STR59## m.p. 132-133.degree. C.28 CH.sub.3 H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR60## m.p. 124-125.degree. C.29 CH.sub.3 H H CH.sub.3 CH.sub.3 ##STR61## ##STR62## m.p. 196-198.degree. C.30 CH.sub.3 H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR63## m.p. 98-99.degree. C.31 Cl 3-Cl H CH.sub.3 CH.sub.3 ##STR64## ##STR65## n.sub.D.sup.20 = 1.570432 Cl 3-Cl H CH.sub.3 CH.sub.3 ##STR66## ##STR67## n.sub.D.sup.20 = 1.571933 Cl 3-Cl H CH.sub.3 CH.sub.3 CH.sub.3 ##STR68## n.sub.D.sup.20 = 1.598834 Cl 3-Cl H CH.sub.3 CH.sub.3 ##STR69## ##STR70## m.p. 168-170.degree. C.35 Cl 3-Cl H CH.sub.3 CH.sub.3 CH.sub.3 ##STR71## n.sub.D.sup.20 = 1.597836 OCH.sub.3 H H CH.sub.3 CH.sub.3 ##STR72## ##STR73## m.p. 123-124.degree. C.37 OCH.sub.3 H H CH.sub.3 CH.sub.3 ##STR74## ##STR75## m.p. 122-123.degree. C.38 OCH.sub.3 H H CH.sub.3 CH.sub.3 CH.sub.3 ##STR76## m.p. 120-121.degree. C.39 ##STR77## H H CH.sub.3 CH.sub.3 ##STR78## ##STR79## m.p. 129-130.degree. C.40 CF.sub.3 H H ##STR80## CH.sub.3 CH.sub.3 ##STR81##41 Cl H H CH.sub.3 (CH.sub.2).sub.5CH.sub.3 CH.sub.3 ##STR82##42 CF.sub.3 H H CH.sub.3 CH.sub.3 ##STR83## ##STR84##43 F H H CH.sub.3 CH.sub.3 ##STR85## ##STR86##44 H 3-Br 5-Br CH.sub.3 CH.sub.3 ##STR87## ##STR88##45 OCH.sub.3 H H CH.sub.3 ##STR89## ##STR90## ##STR91##46 Cl 2-Cl 5-Cl CH.sub.3 C.sub.2 H.sub.5 ##STR92## ##STR93##47 ##STR94## H H CH.sub.3 CH.sub.3 ##STR95## ##STR96##48 CF.sub.3 H H H H CH.sub.3 ##STR97##49 Cl H H CH.sub.3 CH.sub.3 ##STR98## ##STR99##__________________________________________________________________________

EXAMPLE 2

Action against Laodelphax striatellus and Nilaparvata lugens (nymphs)

The test is carried out with growing plants. The procedure is that 4 rice plants (thickness of stem 8 mm) about 20 cm in height are planted into each of a number of pots (diameter 8 cm). The plants in each pot are sprayed on a rotary table with 100 ml of a solution of the test compound in acetone at a concentration of 400 ppm. After the spray coating has dried, each plant is populated with 20 nymphs of the test organisms in the third stage. To prevent the cicadas from escaping, a glass cylinder is slipped over each of the plants and sealed with a gauze top. The nymphs are kept for 10 days on the treated plant until the next development stage has been reached. Evaluation, of mortality (in %) is made 1, 4 and 8 days respectively after treatment by means of a comparison with untreated controls.

The following results are obtained with nymphs of Laodelphax striatellus:

______________________________________ Mortality in %Compound after 1 day after 4 days after 8 days______________________________________1 45 80 907 15 35 508 10 35 609 10 20 50______________________________________

Very good results are also obtained with compounds of the formula I using nymphs of Nilaparvata lungens:

______________________________________ Mortality in %Compound after 4 days after 8 days______________________________________1 60 954 50 705 50 808 35 609 55 70______________________________________

EXAMPLE 3

Ovicidal action against Laodelphax striatellus and Nilapavarta lugens

The test is carried out with growing plants. The procedure is that 4 rice plants (thickness of stem 8 mm) about 20 cm in height are planted into each of a number of pots (diameter 8 cm). The plants in each pot are sprayed on a rotary table with 100 ml of a solution of the test compound in acetone at a concentration of 400 ppm. After the spray coating has dried, each plant is populated with 3 adult females. To prevent the cicadas from escaping, a glass cylinder is slipped over each of the plants and sealed with a gauze top. The females are kept on the treated plants for 4 days for oviposition and then removed. The young cicadas hatch about 8 days after population of the plants and a count is then made. The percentage mortality is assessed by comparing the number of hatched larvae on the treated plants with the number of those on the untreated controls. In this test, the compounds of formula I and Ia have a good ovicidal action.

Claims

1. A compound of the formula I ##STR100## wherein R.sub.1 is hydrogen, halogen, C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, methoxy, ethoxy, benzyl, phenoxy, phenylthio, or phenoxy or phenylthio substituted by a radical selected from the group consisting of halogen, C.sub.1 -C.sub.4 -alkyl, methoxy and ethoxy; each of R.sub.2 and R.sub.3 independently of the other is hydrogen, halogen, C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, methoxy or ethoxy, each of R.sub.4 and R.sub.5 independently of the other is hydrogen or C.sub.1 -C.sub.6 -alkyl; and each of R.sub.6 and R.sub.7 independently of the other is C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, C.sub.3 -C.sub.6 -cycloalkyl, alkoxyalkyl containing a total of 2 to 6 carbon atoms, benzyl, phenyl or phenyl which is substituted by a member selected from the group consisting of halogen, C.sub.1 -C.sub.4 -alkyl, methoxy and ethoxy, or a salt thereof.

2. A compound of the formula Ia according to claim 1 ##STR101## wherein R.sub.1 or R.sub.7 are as defined for formula I in claim 1.

3. A compound according to claim 1 of the formula I or according to claim 2 of the formula Ia, wherein R.sub.1 is hydrogen, halogen, C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, methoxy, benzyl or phenoxy; each of R.sub.2 and R.sub.3 independently of the other is hydrogen, halogen or C.sub.1 -C.sub.4 -alkyl; each of R.sub.4 and R.sub.5 independently of the other is hydrogen or C.sub.1 -C.sub.4 -alkyl; and each of R.sub.6 and R.sub.7 independently of the other is C.sub.1 -C.sub.4 -alkyl, C.sub.3 -C.sub.6 -cycloalkyl, alkoxyalkyl containing a total of 2 to 4 carbon atoms, phenyl or phenyl which is substituted by a member selected from the group consisting of halogen and C.sub.1 -C.sub.4 -alkyl.

4. A compound according to claim 3 of the formula Ia, wherein R.sub.1 is hydrogen, chlorine, methyl, trifluoromethyl, methoxy, benzyl or phenoxy; R.sub.2 is hydrogen, chlorine or methyl; R.sub.3 is hydrogen; each of R.sub.4 and R.sub.5 independently of the other is hydrogen or C.sub.1 -C.sub.4 -alkyl; and each of R.sub.6 and R.sub.7 independently of the other is C.sub.1 -C.sub.4 -alkyl, cyclopropyl, phenyl, or chlorophenyl.

5. A compound according to claim 4 of the formula Ia, wherein R.sub.1 is methyl, trifluoromethyl or benzyl; R.sub.2 is hydrogen or methyl; R.sub.3 is hydrogen; each of R.sub.4 and R.sub.5 independently of the other is methyl or ethyl; and each of R.sub.6 and R.sub.7 independently of the other is C.sub.3 -C.sub.4 -alkyl.

6. A compound according to claim 5 of the formula ##STR102##

7. A compound according to claim 5 of the formula ##STR103##

8. A compound according to claim 5 of the formula ##STR104##

9. A compound according to claim 5 of the formula ##STR105##

10. A compound according to claim 5 of the formula ##STR106##

11. A compound according to claim 5 of the formula ##STR107##

12. A composition for controlling plant destructive insects and representatives of the order Acarina, which contains as active component a compound as claimed in any one of claims 1 to 11, together with suitable carriers and/or other adjuvants.

13. A method of controlling plant destructive insects and representatives of the order Acarina, which comprises applying to said insects or to the locus thereof a pesticidally effective amount of a compound as claimed in any one of claims 1 to 11.

14. A method according to claim 13, wherein the pests to be controlled are plant-destructive cicadas.

15. A method according to claim 14, wherein the pests to be controlled are cicadas in rice crops.