DE3408528A1 - 5-(1-Phenoxyethyl)-1,2,4-oxadiazole derivatives, process for the preparation of these compounds, and herbicides containing them - Google Patents

Abstract

The invention relates to novel 5-(1-phenoxyethyl)-1,2,4-oxadiazole derivatives of the general formula <IMAGE> in which Z represents a 2-quinoxalinyl, 2-benzothiazolyl or 2-benzoxazolyl radical which is optionally monosubstituted or polysubstituted by halogen, C1-C6-alkoxy, C1-C6-alkyl, nitro and/or trifluoromethyl, and R represents hydrogen, a C1-C10-alkyl radical, a C1-C10-alkyl radical which is monosubstituted or polysubstituted by halogen, C1-C6-alkoxy, phenoxy and/or halophenoxy, or is an aryl- C1-C3-alkyl radical, an aryl-C1-C3-alkyl radical which is monosubstituted or polysubstituted by C1-C6-alkyl, halogen, C1-C6-alkoxy, nitro and/or trifluoromethyl, or represents an aromatic hydrocarbon which is optionally monosubstituted or polysubstituted by C1-C6-alkyl, halogen, C1-C6-alkoxy, nitro and/or trifluoromethyl, and to optical isomers thereof, to processes for the preparation of these compounds, and to herbicides containing them.

Description

5- (1-phenoxyethyl) -1,2,4-oxadiazole derivatives,

Process for the preparation of these compounds as well as those containing them Means with herbicidal effect The invention started with new 5- ( 1-Phenoxyetllyl) -1, 2, 4-oxadiazole derivatives according to the preamble of claim 1 Process according to the preamble of claim 20 for producing these compounds as well as agents according to the preamble of claims 21 and 22 containing these active ingredients.

Constitution-analogous compounds with the same direction of action already known (DE-OS 28 01 509). These known compounds are really few effective against perennial weeds and also kallm selective in their use in dicotyledonous crops such as sugar beetroot, rapeseed and sunflower.

The object of the present invention is to provide new Active ingredients which both have an excellent herbicidal effect against grass weeds as also have sufficient selectivity towards dicotyledonous crops.

According to the invention, this object is characterized by what is stated in the claims Item solved.

Advantageous further developments are described in the subclaims.

The compounds according to the invention are surprisingly in the pre and post-emergence methods against a wide range of grass weeds are excellent effective, but at the same time they are obtained from dicotyledonous crops and in addition, well tolerated by some types of grain.

The compounds of the invention are useful, for example, for selective control of weed grasses that are difficult to control, such as Avena fatua, Alopecurus myosuroides, Echinochloa crus galli, Setaria sp., Setaria faberi, Digitaria sanguinalis, Sorghum halepense ,, Poa annua, Bromus sp., Agropyron repens, Cynodon dactylon, Agrostis sp., Lolium sp., Eleusine indica, Rottboellia sp., Cenchrus sp .; in crops such as sugar pulp, cotton, soy, peanut, pea, sunflower, rapeseed and cabbage species and in perennial crops such as orchards, vines and plantations.

The compounds according to the invention could in the pre-emergence process, but are preferably applied postemergence and advantageously have A very good one even at low application rates of 0.05 to 510 kg active ingredient / ha Effect.

The compounds according to the invention are distinguished by those described Effects in particular those in which in the above-mentioned general Formula I R hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert. -Butyl, 2,2-dimethyl-1-propyl, n-pentyl, n-heptyl, n-octyl, n-decyl, chloromethyl, Bromomethyl, fluoromethyl, dichloromethyl, trifluoromethyl, trichloromethyl, methoxymethyl, Ethoxymethyl, phenoxymethyl, 4-chlorophenoxymethyl, chloroethyl, bromoethyl, 2-ethoxyethyl, 2-phenoxyethyl, benzyl, 2-phenylethyl, phenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 3,4-dichlorophenyl, 4-methoxyphenyl, 4-nitrophenyl, 2,4-dichlorophenyl mean.

Among the radicals labeled Z are still, for example, to understand optionally mono- or polysubstituted 2-quinoxalinyl, 2-benzthiazolyl, 2-Benzoxazolyl, 6-chloro-2-quinoxalinyl, 6-fluorine-2-quinoxalinyl 1 6-chloro-2-benzthiazolyl- and 6-chloro-2-benzoxazolyl radicals.

The compounds of the invention occur as optical isomers. The individual isomers and their mixtures are also part of the subject matter of the invention. As a compound with an outstanding effect, in particular 5- (1- (4- (6-chlorobenzothiazol-2-yloxy) -phenoxy) -ethyl) -3-methyl-1,2,4-oxadiazole may be mentioned named and 5- (1- (4- (6-chloroquinoxalin-2-yloxy) -phenyl) -ethyl) -3-methyl-1,2,4-oxadiazole.

The compounds according to the invention can either be used alone or in a mixture be used with each other or with other active ingredients. If necessary, can Desfoliants, crop protection or pesticides, depending on the one desired Purpose to be added.

If a broadening of the spectrum of activity is intended, other biocides can also be added. For example, are suitable as a herbicide effective mixing partners those active ingredients that are described in Weed Abstracts, Vol. 31, No. 7,1982 under the title "List of common names and abbreviations employed for currently used herbicides and plant growth regulators in Weed Abstracts " are.

It has also been found that compositions containing the inventive Compounds mixed with some already known from Weed Abstracts (l.c.) Herbicides, such as phenmedipham, desmedipham and analog biscarbamates, have an increased effect develop herbicidal effects.

The herbicidal effects of these biscarbamates are already known, however This shows that under special conditions there is still room for improvement, for example in the control of very resistant dicotyledon weeds and grass weeds in particular in cultures of sugar pulp and fodder pulp.

Surprisingly, the compounds according to the invention show with these biscarbamates have a considerably increased effect against such weeds and grass weeds without damaging the rubble plants treated with them.

So it changes to a beneficial change in the herbicidal effect of the mentioned biscarbamates, by this even under difficult conditions such as very high application rates, do not have a damaging effect on rubbing while expanding at the same time their spectrum of action on grass weeds.

The present invention therefore also relates to herbicidal mixtures which are characterized in that they contain at least one compound of the general formula I as a mixture with at least one compound of the general formula contain, in which R1 is hydrogen or a C1-C3-alkyl radical, R2 is a C1-C 3 -alkyl radical, X is a C1-C 3 -alkyl radical and / or halogen and / or a CN radical and n is 0, 1, 2 or 3 mean; in a weight ratio of 1:10 to 10: 1, preferably from 1: 3 to 3: 1.

As a particularly suitable mixing partner of the general formula VI the known compounds methyl N- (3- (N '* (3'-methylphenyl) -carbamoyloxy) -phenylcarbamate are to be mentioned, (Phenmedipham) ethyl N- (3- (N'-phenylcarbamoyloxy) -phenyl) -carbamate, (Desmedi and pham) isopropyl N- (3- (N '-ethyl-N' -phenylcarbamoyloxy) -phenylcarbamate.

As a particularly suitable compound of the general formula can 5- [1- (4- (6-chlorobenzothiazol-2-yloxy) -phenoxy) -ethyl) -3-methyl-1,2,4-oxadiazole be used as mixing partners and 5- (1- (4- (6-chloroquinoxalin-2-yloxy) -phenyl) -ethyl) -3-methyl-1,2,4-oxadiazole.

Other suitable biscarbamates that are used in the mixtures according to the invention can be used, those are to be named in the German Offenlegungsschriften No.

842 15 Alt, 156 71 51 and 241 39 33 are listed.

The weight ratio of the components in the mixtures according to the invention should be from about 1:10 to 10: 1, preferably from 1: 3 to 3: 1.

The preferred amounts of active ingredient for selective weed control move from about 0.5 to 5.0 kg / ha for the compounds of the general formula VI and from about 0.05 to 5 kg / ha for the compounds of general formula 1.

The addition of a suitable surface-active agent is also advantageous Substance between 0.25 to 5.0 kg / ha and other effect enhancers such. 13. not phytotoxic oils. The active compounds according to the invention or theirs are expedient Mixtures in the form of preparations such as powders, scattering agents, granulates, solutions, Emulsions or suspensions with the addition of liquid and / or solid carriers or thinning agents and, if necessary, of wetting agents, adhesives, emulsifying agents and / or dispersants, applied, preferably in the form of emulsion concentrates.

Suitable liquid carriers are, for example, water, aliphatic and aromatic hydrocarbons such as benzene, toluene, xylene, cyclohexanone, isophorone, Dimethyl sulfoxide, dimethylformamide, furthermore mineral oil fractions.

Suitable solid carriers are, for example, calcium lignosulfonate, Polyoxyethylene-alkylphenol ethers, naphthalenesulphonic acids and their salts, phenolsulphonic acids and their salts, foraldehyde condensates, fatty alcohol sulfates and substituted benzenesulfonic acids and their salts.

The proportion of the active ingredient (s) in the various preparations can vary within wide limits. For example, the agents contain about 5 to 95 percent by weight active ingredients, about 95 to 5 percent by weight liquid or solid Carriers and optionally up to 20 percent by weight of surface-active substances.

The funds can be applied in the usual way.

For example, with water as a carrier in spray quantities of around 100 up to 1000 liters / ha. An application of the means in the so-called low-full-volume and ultra-low-volume procedure is just as possible as their application in the form of so-called microgranules.

The following ingredients are used to produce the preparations: A. wettable powder a) 40 percent by weight active ingredient 25 percent by weight clay minerals 20 percent by weight colloidal silica 10 percent by weight cell pitch 5 percent by weight surface-active substances based on a mixture of the calcium salt of ligninsulphonic acid with alkylphenol polyglycol ether b) 25 percent by weight active ingredient 60 percent by weight of kaolin 10 percent by weight of colloidal silica 5 percent by weight of surface-active substances based on the sodium salt of N-methyl-N-oleyl-taurine and the calcium salt of ligninsulphonic acid c) 10 percent by weight of active ingredient 60 percent by weight of clay minerals 15 percent by weight of colloidal silica 10 percent by weight of colloidal silica 10 percent by weight Substances based on the sodium salt of N-methyl-N-oleyl-taurine and the calcium salt of lignin sulfonic acid B. Paste 45 percent by weight active ingredient 5 percent by weight sodium aluminum silicate 15 percent by weight percent cetyl polyglycol ether with 8 moles of ethylene oxide 2 percent by weight spindle oil 10 percent by weight polyethylene glycol 23 parts water C. Emulsion concentrate a) 25 percent by weight active ingredient 15 percent by weight cyclohexanone 55 percent by weight xylene 5 percent by weight mixture of nonylphenyl polyoxyethylene or calcium dodecylbenzenesulfonate mixture by weight 6 percent by weight cyclohexylbenzenesulfonate 6 percent by weight b) 36 percent by weight cyclohexylbenzenesulfonate mixture of nonylphenyl polyoxyethylene or calcium dodecylbenzenesulfonate 36 percent by weight mineral oil with a high paraffin content The new compounds of the general formula I according to the invention can be prepared, for example, by a) compounds of the general formula in the presence of a solvent and, if appropriate, in the presence of a catalyst with compounds of the general formula or b) by converting compounds of the general formula ZX IV with Hydwshinonderivaten of the formula allowed to react in the presence of an acid-binding agent and / or a catalyst, in which R and Z are as defined above and X is a halogen atom, preferably a chlorine or bromine atom.

The reaction partners are converted between -10 and 1500C, in general, however, between room temperature and reflux temperature of the corresponding Reaction mixture.

The reaction time is 1 to 72 hours. Usually done the reactions at normal pressure or slightly overpressure.

The reactants are used to synthesize the compounds according to the invention used in approximately equimolar amounts. Suitable Reaction media are solvents inert towards the reactants. The choice of solution or The suspension medium depends on the use of the corresponding alkyl halides and the acid acceptors used. As a solvent or suspending agent are for example called aliphatic and aromatic hydrocarbons, such as petroleum ethers, Cyclohexane, hexane, heptane, benzene, toluene1 xylenes; halogenated hydrocarbons, such as methylene chloride, ethylene chloride, chlorobenzene, chloroform, carbon tetrachloride, Tetrachlorethylene; Ethers, such as diethyl ether, diisopropyl ether, anisole, dioxane, tetrahydrofuran; Carboxylic acid nitriles such as acetonitrile, propionitrile; Carboxamides such as dimethylformamide; Dimethyl sulfoxide; Ketones such as acetone, diethyl ketone, methyl ethyl ketone and mixtures such solvents with each other. In some cases, the partner serve as a solvent itself.

Organic bases, such as, for example, are suitable as acid acceptors Triethylamine, trimethylamine, N, N-dimethylaniline, pyridine and pyridine bases (4-dimethylaminopyridine) or inorganic bases such as oxides, hydroxides, carbonates, hydrogen carbonates and Alcoholates of alkali and alkaline earth metals (KOH, NaOH, Na2-CO3, K2CO3).

Liquid bases such as pyridine can also be used as solvents can be used.

The presence of a reaction catalyst can be advantageous. as Catalysts are potassium iodide and onium compounds, such as quaternary ammonium, Phosphonium and arsonium compounds and sulfonium compounds. Also suitable are polyglycol ethers, especially cyclic ones, such as 18-crown-6, and tertiary ones Amines such as tributylamine.

Preferred compounds are quaternary ammonium compounds, such as for example benzyltriethylammonium chloride and tetrabutylammonium bromide.

The according to the above-mentioned process according to the invention Compounds can be isolated from the reaction mixture by the usual methods are, for example, by distilling off the solvent used normal or reduced pressure, by precipitation with water or by extraction.

A higher degree of purity can usually be achieved by column chromatography Purification as well as obtained by fractional distillation or crystallization will.

The compounds according to the invention are generally almost color- and odorless liquids as well as crystals that are sparingly soluble in water, Conditionally soluble in aliphatic hydrocarbons such as petroleum ether, hexane, pentane and cyclohexane, easily soluble in halogenated hydrocarbons such as chloroform, Methylene chloride and carbon tetrachloride, aromatic hydrocarbons such as Benzene, toluene and xylene, ethers such as diethyl ether, tetrahydrofuran and dioxane, carboxylic acid nitriles such as acetonitrile, alcohols such as methanol and ethanol, carboxamides such as dimethylformamide and sulfoxides such as dimethyl sulfoxide.

The compounds of general formula 1 always have an asymmetric one Carbon atom C *. In synthesis, the drugs usually fall as racemic Mixture and can in a known manner, for example by fractional crystallization, split into the optical antipodes.

The synthesis of an optically pure compound of the formula I is possible if one uses an optically unambiguous 2-halopropionic acid in their production goes out. The optical antipodes of I have different biological activity; As a rule, the D-form is more herbicidally effective.

The starting compounds for the manufacture of the invention Compounds are known per se or can be prepared by methods known per se will.

The following examples explain the production of the invention Links.

B E I S P I E L 1 5- {1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-methyl-1,2,4-oxadiazole 22.2 g (0.08 mol) 4- (6-chlorobenzothiazol-2-yloxy) phenol, 11.0 g (0.08 mol) potassium carbonate and 15.28 g (0.08 mol) of 5- (1-bromoethyl) -3-methyl-1,2,4-oxadiazole are in 120 ml Suspended acetonitrile. It is annealed for three hours at + 600C. After standing 1153 g (0.008 mol) of 5- (1-bromoethyl) -3-methyl-1,2,4-oxadiazole are added overnight at room temperature added and stirred for 2 hours at + 600C.

The reaction mixture is concentrated in vacuo. The oily crystalline one The residue is taken up in 500 ml of ethyl acetate and washed once with 250 ml of water. the aqueous phase is extracted once with 250 ml of ethyl acetate, the combined organic Phases are washed twice with 250 ml of water each time, dried and dried with MgSO4 concentrated in vacuo.

Yield: 16.87 g = 54.37 Vo of theory, melting point: 110 ° C. TLC: 1 spot, mobile phase: Methylene chloride / methanol 95/5 Rf value: 0.758 analysis: calculated: C H N S 55.74 3.64 10.83 8.27 found: 55.83 4.06 10146 8.42 The other represent compounds according to the invention: Example according to the invention Compounds Physical No. Constant 2 5- [1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3- ethyl-1,2,4-oxadiazole m.p .: 95-97 ° C 3 5- [1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-isopropyl-1,2, 4-oxadiazole M.p .: 51-53 ° C 4- [1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-n-propyl-1,2,4-oxadiazole M.p .: 60-62 ° C 5- [1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-phenyl-1,2,4-oxadiazole M.p .: 94-96 ° C 6- [1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-methyl-1,2,4-oxadiazole M.p .: 83-85 ° C 7 5- [1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-ethyl-1,2,4-oxadiazole M.p .: 65-66 ° C 8 5- [1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-isopropyl-1,2,4-oxadiazole nD20: 1.4254 9 5- [1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-n-propyl-1,2,4-oxadiazole nD20: 1.4041 10 5- [1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-phenyl-1,2,4-oxadiazole M.p .: 83-84 ° C 11 5- [1- [4- (6-chloroquinoxalin-2-yloxy) -phenoxy] -ethyl} -3-methyl-1,2,4-oxadiazole M.p .: 113-115 ° C 12 5- [1- [4- (6-chloroquinoxalin-2-yloxy) -phenoxy] -ethyl} -3-ethyl-1,2,4-oxadiazole nD20: 1.6021 13 5- [1- [4- (6-chloroquinoxalin-2-yloxy) -phenoxy] -ethyl} -3-isopropyl-1,2,4-oxadiazole nD20: 1.5897 14 5- [1- [4- (6-chloroquinoxalin-2-yloxy) -phenoxy] -ethyl} -3-n-propyl-1,2,4-oxadiazole M.p .: 78-80 ° C 15 5- [1- [4- (6-chloroquinoxalin-2-yloxy) -phenoxy] -ethyl} -3-phenyl-1,2,4-oxadiazole M.p .: 98-104 ° C 16 5- [1- [4- (Benzothioazol-2-yloxy) -phenoxy] -ethyl} -3-methyl-1,2,4-oxadiazole nD20: 1.6023 17 5- [1- [4- (Benzoxazol-2-yloxy) -phenoxy] -ethyl} -3-methyl-1,2,4-oxadiazole M.p .: 69-71 ° C The following examples explain the possible applications of the compounds according to the invention, which are in the form of the above-indicated cell preparations took place.

EXAMPLE 18 In the greenhouse, those listed in the table were used Compounds according to the invention at an application rate of 3.0 kg active ingredient / ha, emulsified in 500 liters of water / ha, on Setaria and black foxtail as test plants in advance and post-emergence injection.

3 weeks after the treatment, the treatment result was rated, where 0 = no effect and 4 = destruction of the plants.

As can be seen from the table, a destruction was usually carried out of the test plants achieved.

Nachauflauf according to the invention connection Setaria black foxtail 5- (1- (4- (6-chlorobenzothiazol-2-yloxy) -phenoxy) -ethyl) -3-methyl-1,2,4-oxadiazole 4 4 5- (1- (4- (6-chlorobenzothiazol-2-yloxy) -phenoxy) -ethyl) -3-isopropyl-1,2,4-oxadiazole 4 5- [1- (4- (6-chlorobenzothiazol-2-yloxy) -phenoxy) -ethyl) -3-n-propyl-1,2,4-oxadiazole 4 4 5- (1- (4- (6-chlorobenzothiazol-2-yloxy) -phenoxy) -ethyl) -3-phenyl-1,2,4-oxadiazole 4 4 5- (1- (4- (6-chloroquinoxalin-2-yloxy) -phenoxy) -ethyl) -3-methyl-1,2,4-oxadiazole 4 4 5- (1- (4- (Benzothiazol-2-yloxy) -phenoxy) -ethyl) -3-methyl-1,2,4-oxadiazole 4 5- (1- (4- (Benzoxazol-2-yloxy ) -phenoxy) -ethyl) -3-methyl-1,2,4-oxadiazole 4 4 Compounds according to the invention Nachauflauf Setaria black foxtail 5- (1- (4- (6-chloroquinoxalin-2-ySoxy) -phenoxy) -ethyl) -3-ethyl-1,2,4-oxadiazole 4 4 5- [1- (4- (6-chloroquinoxalin-2-yloxy) -phenoxy) -ethyl-3-isopropyl-1,2,4-oxadiazole 4 4 5- [1- (4- (6-chloroquinoxalin-2-yloxy) -phenoxy) -ethyl-3-n-propyl-1,2,4-oxadiazole 4 4 5- [1- (4- (6-chloroquinoxalin-2-yloxy) -phenoxy) -ethyl-3-phenyl-1,2,4-oxadiazole 4 4 13EISPIL'L 19 In the greenhouse the following were listed Plants after emergence with the compound according to the invention in one application rate of 0.1 kg active ingredient / ha treated. The compound was used as an emulsion for this purpose Sprayed evenly over the plants with 500 liters of water / ha. Here shows 3 weeks after the treatment, the compound of the invention has a high selectivity with excellent Effect against the weeds.

14 days after the treatment, the success of the treatment was rated according to the rating scale 0 to 10, where O = total destruction and 10 = no effect. 0> o rß E - r - -i 0> H 0> -i according to the invention 0 o E a cH Connection c E <v A o 0> St rl F: td E P. r (YI m E; 4> 111 0> X oo S on A 60 « O> O 0> 1 o 4 X 4 Q 5- (- (4- (6-chloro- benzothiazole 2- yloxy) -pbenoxy) - 0 0 0 0 0 0 0 10 10 10 10 10 10 ethyl) -3-methyl- 1,2,4-oxadiazole 5- (1- (4- (6-chloroquin- oxalin-2-yloxy) - phenoxy) -ethyl) -3- methyl-1,2,4-oxa- 0 0 0 0 0 0 0 10 10 10 10 10 10 diazole EXAMPLE 20 After emergence, the plants listed below were treated in the greenhouse with the active ingredients listed below or a mixture thereof and, for this purpose, sprayed evenly over the plants as an emulsion with 500 liters of water / ha.

3 weeks after the treatment, the treatment result was rated, where 0 = destruction of the plants and 10 = no damage.

As can be seen from the table, the mixture according to the invention had a stronger effect on numerous problem weeds while completely sparing the sugar pulp than the individual component. O Q 4 X (d - at the ; E; r <h U h ca C ac, Q to H a GH 60 HW o rl H Expenditure according to the invention- o S w = O to [s 0> - close - 3 o to r (oo ri ri 4> Connection set N Components kg / ha 5- (1- (4- (6-chloro- benzothiazol-2-yl- oxy) -phenoxy) -ethyl) - 3-methyl-1,2,4-oxa- diazole (I) 0.15 10 0 0 0 0 0 0 0 10 10 Phenmedipham (II) 0.7 10 5 8 10 8 8 7 6 OO I + II 0.7 + 0.15 10 0 0 0 0 0 0 0 0 0 5- (l- (4- (6-chloroquinoxalln- 2-yloxy) -phenoxy) -ethyl) - 3-methyl-1,2,4-oxadiazole. III 10 0 0 0 0 0 0 0 10 10 1 + III 10 0 0 0 0 0 0 0 0 0

Claims (1)

PATENT APPLICATION (1.) 5- (1-Phenoxyethyl) -1,2,4-oxadiazole derivatives of the general formula in which Z is a 2-quinoxalinyl, 2-benzothiazolyl or 2-benzoxazolyl radical optionally substituted one or more times by halogen, C1-C6-alkoxy, C1-C6-alkyl, nitro and / or trifluoromethyl and R is hydrogen, a C1-ClO -Alkyl radical, a C1-C10-alkyl radical substituted one or more times by halogen, i 6 C1-C6-alkoxy, phenoxy and / or halophenoxy, an aryl-C1-C3-alkyl radical, one or more times by C1-C6-alkyl, Halogen, C1-C6-alkoxy, nitro and / or trifluoromethyl-substituted aryl-C1-C3-alkyl radical or an aromatic which is optionally substituted one or more times by C1-C6-alkyl, halogen, C1-C6-alkoxy, nitro and / or trifluoromethyl Represent hydrocarbons, as well as their optical isomers. 2. 5- (1-phenoxyethyl) -1,2,4-oxadiazole derivatives according to claim i, wherein Z is 2-quinoxalinyl, 2-benzthiazolyl, 2-benzoxazolyl, 6-chloro-2-benzthiazolyl or 6-chloro-2-benzoxazolyl and R methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, 2,2-dimethyl-1-propyl, n-pentyl, n-heptyl, n-octyl, n-decyl, chloromethyl, Bromomethyl, fluoromethyl, dichloromethyl, trifluoromethyl, trichloromethyl, methoxymethyl, Ethoxymethyl, phenoxymethyl, 4-chlorophenoxymethyl, chloroethyl, bromoethyl, 2-ethoxyätllyl, 2-phenoxyethyl, chloroethyl, 3-chlorophenyl, 4-chlorophenyl, 3,4-dichlorophenyl, 4-methoxyphenyl, 4-nitrophenyl or 2,4-dichlorophenyl. 3. 5- {1- [4- (6-chlorobenzothiazol-2-yloxy) phenoxy] -ethyl} - 3-methyl-1,2,4-oxadiazole 4. 5- {1- [4- (6-chlorobenzothiazole -2-yloxy) -phenoxy-7-ethyl-3 -3-ethyl-1,2,4-oxadiazole 5. 5- {1- [4- (6-Chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-isopropyl -1,2,4-oxadiazole 6. 5- {1- [4- (6-chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-propyl-1,2,4-oxadiazole 7. 5- { 1- [4- (6-Chlorobenzothiazol-2-yloxy) -phenoxy] -ethyl} -3-phenyl-1,2,4-oxadiazole 8. 5- {1- [4 - (6-Chlorobenzoxazol-2-yloxy ) -phenoxy] -ethyl} -3-methyl-1,2,4-oxadiazole 9. 5- {1- [4- (6-Chlorobenzoxazol-2-yloxy) -phenoxy] -ethyl} -3-ethyl-1 , 2,4-oxadiazole 10. 5- {1- [4- (6-Chlorobenzoxazol-2-yloxy) -phenoxy] -ethyl} -3-isopropyl-1,2,4-oxadiazole 11. 5- {1- [4- (6-chlorobenzoxazol-2-yloxy) -phenoxy] -ethyl} -3-propyl-1,2,4-oxadiazole 12. 5- {1- [4- (6-chlorobenzoxazol-2-yloxy) - phenoxy] -ethyl} -3-phenyl-1,2,4-oxadiazole 13. 5- {1- [4- (6-chloroquinoxalin-2-yloxy) -phenoxy7-ethyl3-3-methyl-1,2,4 -oxadiazole 14. 5- {1- [4- - (6-Chloroquinoxalin-2-yloxy) -phenoxy] -ethyl} -3-ethyl-1,2,4-oxadiaz ol 15. 5- {1- [4- (6-Chloroquinoxalin-2-yloxy) -phenoxy] -ethyl} -3-isopropyl-1,2,4-oxadiazole 16. 5- {1- [4- (6 -Chloroquinoxalin-2-yloxy) -phenoxy] -ethyl} -3-propyl-1,2,4-oxadiazole 17. 5- - / 4- (6-chloroquinoxalin-2-yloxy) -phenoxy] -ethyl} -3 -phenyl-1,2,4-oxadiazole 18. 5- £ 1- / 0- (benzothiazol-2-yloxy) -phenoxy] -ethyl} -3-methyl-1,2,4-oxadiazole 19. 5- £ 1- / 4- (Benzoxazol-2-yloxy) -phenoxy] -ethyl} -3-methyl-1,2,4-oxadiazole 20. Process for the preparation of 5- (1-phenoxyethyl) -1,2,4- Oxadiazole derivatives according to paints 1 to 19, characterized in that a) compounds of the general formula in the presence of a solvent and, if appropriate, in the presence of a catalyst with compounds of the general formula or b) by converting compounds of the general formula ZX IV with hydroquinone derivatives of the formula allowed to react in the presence of an acid-binding agent and / or a catalyst, in which R and Z are as defined above and X is a halogen atom, preferably a chlorine or bromine atom. 21. Means with herbicidal action, characterized by a content of at least one connection according to claims 1 to 19. 22. Agent with herbicidal action, characterized by a content of at least one compound according to Claims 1 to 19 in a mixture with at least one compound of the general formula in which R1 is hydrogen or a C1-C3-alkyl radical, R2 is a C1-C3-alkyl radical, X is a C1-C3-alkyl radical and / or halogen and / or a CN radical and n is 0, 1, 2 or 3; in a weight ratio from 1:10 to 10: 1, preferably from 1: 3 to 3: 1. 23. Agent with herbicidal activity according to claim 22, characterized by a content of 5- (1- (4- (6-chlorobenzothiazol-2-yloxy) -phenoxy) -ethyl) -3-methyl-1,2,4-oxadiazole in a mixture with methyl N- (3- (N '- (3-methylphenyl) -carbamoyloxy) -phenyl) -carbamate, Ethyl N- (3- (N'-phenylcarbamoyloxy) -phenyl) -carbamate or isopropyl-N- (3- (N'-ethyl-N'-phenylcarbamoyloxy) -phenyl) -carbamate. 24. Means according to claim 21 to 23 in a mixture with carrier and / or Auxiliary materials.