Cyclopropanecarboxylic Acid-Phenoxy-.Alpha.-Vinyl-Benzyl Esters, Processes for Producing Them, and Their Use in Combating Pests

The present invention relates to cyclopropanecarboxylic acid-phenoxy-.alpha.-vinyl-benzyl esters, to processes for producing them, and to their use in combating pests.

The cyclopropanecarboxylic acid esters have the formula ##STR3## in which Y is chlorine or bromine, and R.sub.1 is --CH.dbd.CH.sub.2 or ##STR4##

The compounds of the formula I are produced by methods known per se, for example as follows: ##STR5##

In the formulae II to VI, the symbols R.sub.1 and Y have the meanings given under the formula I.

X in the formulae III and IV is a halogen atom, particularly chlorine or bromine, and R in the formula VI is C.sub.1 -C.sub.4 -alkyl, especially methyl or ethyl. Suitable acid-binding agents for the processes 1 and 2 are in particular tertiary amines, such as trialkylamine and pyridine, also hydroxides, oxides, carbonates and bicarbonates of alkali metals and alkaline-earth metals, and also alkali metal alkoholates, such as potassium-t-butylate and sodium methylate. The water-binding agent used for the process 3 can be for example dicyclohexylcarbodiimide. The processes 1 to 4 are performed at a reaction temperature between -10.degree. and +120.degree. C., usually between 20.degree. and 80.degree. C., under normal or elevated pressure, and preferably in an inert solvent or diluent. Suitable solvents or diluents are for example: ethers and ethereal compounds such as diethyl ether, dipropyl ether, dioxane, dimethoxyethane and tetrahydrofuran; amides such as N,N-dialkylated carboxylic acid amides; aliphatic, aromatic as well as halogenated hydrocarbons, especially benzene, toluene, xylene, chloroform and chlorobenzene; nitriles such as acetonitrile: dimethylsulfoxide and ketones such as acetone and methyl ethyl ketone.

The starting materials of the formula II, IV and VI are known and can be produced by methods analogous to known methods. Disclosures relating to such starting materials may, for example, be found in DOS No. 2,142,546. The preparation of starting materials III and V is described hereinafter.

Unless homogeneous optically active starting materials are used in the production process, the compounds of the formula I are obtained as mixtures of various optically active isomers. The different isomeric mixtures can be separated by known methods into the individual isomers. By `compound of the formula I` is meant both the individual isomers and mixtures thereof.

The compounds of the formula I are suitable for combating various animal and plant pests. They are suitable in particular for combating insects and phytopathogenic mites and ticks, for example of the orders Lepidoptera, Coleoptera, Homoptera, Heteroptera, Diptera, Acarina, Thysanoptera, Orthoptera, Anoplura, Siphonaptera, Mallophaga, Thysanura, Isoptera, Psocoptera and Hymenoptera.

Compounds of the formula I are especially suitable for combating insects which damage plants, particularly insects which damage plants by eating, in crops of ornamental plants and useful plants, especially in cotton crops, (for example against Spodoptera littoralis and Heliothis virescens) and in crops of vegetables (for example against Leptinotarsa decemlineate and Myzus persicae). The active substances of the formula I also exhibit a very favourable action against flies, such as Musca domestica, and against mosquito larvae.

The acaricidal and insecticidal action can be substantially broadened and adapted to suit given circumstances by the addition of other insecticides and/or acaricides. Suitable additives are, for example, organic phosphorus compounds, nitrophenols and derivatives thereof, formamidines, ureas, other pyrethrin-like compounds, and also carbamates and chlorinated hydrocarbons.

Compounds of the formula I are combined particularly advantageously also with substances which have a synergistic or intensifying effect on pyrethroids. Examples of such compounds are, inter alia, piperonylbutoxide, propynyl ethers, propynyl oximes, propynyl carbamates and propynyl phosphonates, 2-(3,4-methylenedioxyphenoxy)-3,6,9-trioxaundecane (Sesamex or Sesoxane), S,S,S-tributylphosphorotrithioates and 1,2-methylenedioxy-4-(2-octylsulfonyl)-propyl)-benzene.

Compounds of the formula I can be used on their own or together with suitable carriers and/or additives. Suitable additives can be solid or liquid and they correspond to the substances common in formulation practice, such as natural or regenerated substances, solvents, dispersing agents, wetting agents, adhesives, thickeners, binders and/or fertilisers.

The compositions according to the invention are produced in a manner known per se by the intimate mixing and/or grinding of the active substances of the formula I with suitable carriers, optionally with the addition of dispersing agents or solvents which are inert to the active substances. The active substances can be obtained and used in the following forms:

solid preparations: dust, scattering agents, granules (coated granules, impregnated granules and homogeneous granules);

liquid preparations:

(a) water-dispersible concentrates of active substance: wettable powders, pastes or emulsions;

(b) solutions.

The content of active substance in the compositions described is between 0.1 and 95%, it is to be mentioned in this respect that with application from an aeroplane, or by other suitable devices, concentrations of up to 99.5% or even the pure active substance can be used.

The active substances of the formula I can be formulated for example as follows (parts are by weight):

The following substances are used to produce (a) a 5% dust and (b) a 2% dust:

The active substance is mixed and ground with the carriers.

The following ingredients are used to produce a 5% granulate:

The active substance is mixed with epichlorohydrin and dissolved in 6 parts of acetone, and the polyethylene glycol and cetyl polyglycol ether are then added. The solution obtained is sprayed onto kaolin and the acetone is subsequently evaporated off in vacuo.

The following constituents are used to produce (a) a 40%, (b) and (c) a 25%, and (d) a 10% wettable powder:

The following substances are used to produce (a) a 10%, (b) a 25% and (c) a 50% emulsifiable concentrate:

Emulsions of the concentration required can be prepared from these concentrates by dilution with water.

The following constituents are used to produce (a) a 5% spray and (b) a 95% spray:

The invention is further illustrated by the following Examples.

(a) With stirring and in a nitrogen atmosphere, 150 ml tetrahydrofuran in which 12-14 g/h acetylene was introduced were added successively (in 3 hours) to a suspension of ethylmagnesia-bromide (produced with 30 g ethylbromide and 6 g magnesia).

The resulting solution of ethynylmagnesia-bromide was cooled to 0.degree. C. and then added dropwise to a solution of 35.8 g 3-phenoxy-benzaldehyde in 25 ml tetrahydrofuran.

After 8 hours stirring at room temperature, the reaction solution was added dropwise to 750 ml of a saturated ammoniachloride solution. After 30 minutes stirring the organic phase was separated, dried with sodium sulfate and chromatographed over silicagel with hexan and ether 4:1 as diluent.

There was obtained 24 g of the compound of the formula ##STR6## having a refractive index of n.sub.D.sup.32.degree. =1.5798.

(b) With stirring and under skylight lighting, 16 g bromine in 20 ml CCl.sub.4 were added successively (in 2 hours) at a temperature of 10.degree. to 20.degree. C. to a solution of 22.4 g 3-phenoxy-.alpha.-(ethynyl)-benzylalcohol in 80 ml CCl.sub.4.

After stirring for 10 hours at room temperature, the CCl.sub.4 was distilled off.

There was obtained the compound of the formula ##STR7## having a refractive index of n.sub.D.sup.35.degree. =1.6210.

With stirring, at room temperature and under normal pressure, hydrogen was introduced (3.37 l H.sub.2 ; 0.degree. C./760 mm Hg) in a solution of 33.7 3-phenoxy-.alpha.-ethynylbenzylalcohol in 340 ml dioxan and 1.7 g Lindlar catalysator.

After filtration and dilution with water the product was extracted with ether. After drying of the ether extracts with sodium sulfate and evaporation of the ether, the product was chromatographed over silicagel with hexan and ether 1:1 as eluent.

There was obtained the compound of formula ##STR8## having a refractive index of n.sub.D.sup.32.degree. =1.5832.

3.2 g of pyridine in 10 ml of benzene is added dropwise at 5.degree. C., with stirring, to 8 g of 3-phenoxy-.alpha.-vinyl-benzyl alcohol in 30 ml of benzene. After the addition of 14 g of 2,2-dimethyl-3-(1-bromo-2,2-dichloro-2-bromoethyl)-cyclopropanecarboxylic acid chloride at 10.degree. C., the mixture is stirred for 2 hours at room temperature, and is allowed to stand for a further 10 hours at this temperature. The reaction mixture is diluted with ice water; the organic layer is extracted three times with 100 ml of 3% HCl each time, and subsequently three times with 100 ml of 3% sodium bicarbonate each time; the organic phase is dried with sodium sulfate, and the benzene is distilled off. There is obtained the compound of the formula ##STR9## as colourless oil having a refractive index of n.sub.D.sup.40.degree. =1.5776. In an analogous manner is also obtained the compound of the formula ##STR10##

Cotton plants were sprayed with a 0.05% aqueous emulsion of the active substance (obtained from 10% emulsifiable concentrate).

After drying of the coating, larvae of Spodoptera littoralis in the L.sub.3 -stage and of Heliothis virescens in the L.sub.3 -stage were placed onto the cotton plants. The test was carried out at 24.degree. C. with 60% relative humidity.

Compounds according to Example 1 exhibited in the above test a good insecticidal stomach-poison action against larvae of Spodoptera littoralis and Heliothis virescens.

Phaseolus vulgaris plants were infested, 12 hours before the test for acaricidal action, with an infested piece of leaf from a mass culture of Tetranychus urticae. The transferred mobile stages were sprayed with the emulsified test preparations from a chromatography-sprayer in a manner ensuring no overflow of the spray liquor. An assessment was made after 2 and 7 days, by examination under a binocular microscope, of the living and of the dead larvae, adults and eggs, and the results were expressed as percentages. The treated plants were kept during the "holding time" in greenhouse compartments at 25.degree. C.

Compounds according to Example 1 exhibited in the above test a good action against adults, larvae and eggs of Tetranychus urticae.

(A) Rhipicephalus bursa

For each concentration, 5 adult ticks and 50 tick larvae, respectively, were counted into a small glass test tube, and immersed for 1 to 2 minutes in 2 ml of an aqueous emulsion from a dilution series of 100, 10, 1 and 0.1 ppm of test substance. The tubes were then sealed with a standardised cotton plug, and inverted so that the active-substance emulsion could be absorbed by the cotton wool.

The evaluation in the case of the adults was made after 2 weeks and in the case of the larvae after 2 days. There were two repeats for each test.

(B) Boophilus microplus (larvae) With a dilution series analogous to that of Test A, tests were carried out with 20 sensitive larvae and OP-resistant larvae, respectively (resistance is with respect to diazinon compatibility).

Compounds according to Example 1 were effective in these tests against adults and larvae of Rhipicephalus bursa and against sensitive and OP-resistant larvae, respectively, of Boophilus microplus.