DE2937645A1 - Selective herbicide tetra:hydro-3-pyranyl benzyl ether derivs. - prepd. e.g. by reaction of a tetra:hydro-3-pyranol alcoholate with a benzyl halide, mesylate or tosylate - Google Patents

Abstract

New tetrahydropyranyl benzyl ether derivs. are cpds. of formula (I) (where R is opt. substd. phenyl; R1 is H, alkyl, alkenyl, alkynyl, cycloalkyl or opt. substd. phenyl; R2 is H or alkyl; R3 is H or alkyl; and R4-R7 are H, alkyl, alkoxy, alkoxyalkyl, alkoxyalkoxy, haloalkyl or opt. substd. phenyl, or R4 + R5, R5 + R7 or R5 + %6 is alkylene). (I) are herbicides useful as selective herbicides against grasses. They show good selectivity with respect to important cultivated plants. (I) can also be used as plant growth regulants (defoliants, desiccants, haulm-killing agents, germination- inhibiting agents). In contrast to known chloroacetanilides, (I) are active against Alopecurus or Poa annua, as well as against other grasses such as Digitaria, Echinochloa, Panicum and Setaria.

Description

Tetrahydropyranether derivatives, processes for their preparation as well as their use as herbicides The present invention relates to new tetrahydropyran ether derivatives, several processes for their preparation and their use as herbicides, in particular as selective herbicides.

It has already become known that chloroacetanilides such as 2-ethyl-6-methyl-N- (l "-methyl-2" -methoxy-ethyl) -chloroacetanilide, as herbicides, in particular for combating grass-like weeds (Compare DE-OS 23 28 340). However, these compounds are in their selectivity not always entirely satisfactory.

There were new tetrahydropyran ether derivatives of the general formula in which R represents optionally substituted phenyl, R 'represents hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl or optionally substituted phenyl, R2 represents hydrogen or alkyl, R3 represents hydrogen or alkyl, R4 to R7 are identical or different and are hydrogen , Alkyl, alkoxy, alkoxyalkyl, alkoxyalkoxy, haloalkyl or optionally substituted phenyl, and R4 and R5, R6 and R7 and R5 and R6 each jointly represent an alkylene bridge.

It has also been found that the tetrahydropyran ether derivatives of the formula (I) are obtained if a) alcoholates of 3-hydroxytetrahydropyran derivatives of the formula in which R 'to R7 have the meaning given above, and M is an alkali or alkaline earth metal, with a compound of the formula Y - CH2 - R (III) in which R has the meaning given above, and Y is halogen, in particular Chlorine or bromine, the mesylate or tosylate radical, is reacted in the presence of a diluent, or when b) pentanediols of the formula in which R and R1 to R7 have the abovementioned terms, heated in the presence of an acidic catalyst and, if appropriate, in the presence of a diluent.

It has also been found that the tetrahydropyran ether derivatives of Formula (I) strong herbicidal, in particular also selective herbicidal properties exhibit.

Surprisingly, the tetrahydropyran ether derivatives according to the invention are the known herbicides, such as 2-ethyl-6-methyl-N- (l'-methyl-2'-methoxy-ethyl) -chloroacetanilide, superior in herbicidal activity and also show excellent selectivity in important crops.

The active ingredients according to the invention thus represent a significant enrichment herbicidal agents, especially grass herbicides.

The tetrahydropyran ether derivatives according to the invention are by Formula (I) generally defined. In this formula, R preferably stands for optionally substituted phenyl, one or more of the same or different Can carry substituents. The following are preferably mentioned as substituents: halogen; Alkyl and alkoxy each having 1 to 4 carbon atoms; Haloalkyl, haloalkoxy and haloalkylthio each having up to 4 carbon atoms and up to 5 halogen atoms, in particular with up to 2 carbon and up to 3 identical or different Halogen atoms, where the halogens are in particular fluorine, chlorine and Prom; the Methylenedioxo group and the tri-, tetra- or pentamethylene radical. Ri preferably stands for hydrogen, straight-chain or branched alkyl with 1 to 6 carbon atoms, Cycloalkyl with 3 to 6 carbon atoms, for alkenyl and alkynyl with 2 each to 4 carbon atoms and optionally substituted phenyl, where as Substituents are preferred: halogen, alkyl and alkoxy with each 1 or 2 carbon atoms and haloalkyl with up to 2 carbon and up to to 3 identical or different halogen atoms, such as in particular fluorine and chlorine.

R2 and are identical or different and are preferably hydrogen and alkyl of 1 to 4 carbon atoms. B R5, R6 and R7 are identical or different and are preferably hydrogen, straight-chain or branched alkyl with 1 to 6 carbon atoms, for alkoxy, alkoxyalkyl and alkoxyalkoxy with each 1 to 4 carbon atoms in each alkyl part, haloalkyl with up to 2 carbon and up to 3 identical or different halogen atoms, in particular as halogens Fluorine, chlorine and bromine stand, as well as optionally substituted phenyl, where the ito questions already mentioned under Rn are preferably used as substituents. R4 and R5 as well as R6and R7 also each jointly preferably represent a two- to five-membered structure Methylene bridge. R5and R6 also preferably together represent a di- or Trimethylene bridge.

Those compounds of the formula (I) are very particularly preferred in which R is optionally represented by fluorine, chlorine, bromine, methyl, ethyl, isopropyl, Methoxy, trifluoromethyl, trifluoromethyl or methylenedioxo substituted phenyl stands; R1 represents hydrogen, methyl or ethyl; R2 for hydrogen, methyl, Is ethyl or isopropyl; R3 represents hydrogen, methyl, ethyl or isopropyl; 5 R5, R6 and R7 are identical or different and represent hydrogen, methyl, ethyl, Methyl, ethoxy, methoxymethyl, ethoxymethyl, methoxyethyl, nethoxymethoxy, methoxyethoxy, Ethoxyethoxy or phenyl, RX and R5 and R6 and R7 each together represent a di-, tri-, tetra- or pentamethylene bridge, and R5 and R6 together stand for a di- or trimethylene bridge.

If the sodium alcoholate of 3-hydroxytetrahydropyran and 2-methylbenzyl bromide are used as starting materials, the course of the reaction can be represented by the following equation: (process variant a): If 2- (2-fluorobenzyloxy) pentane-1,5-diol is used as the starting material and p-toluenesulfonic acid as the catalyst, the course of the reaction can be represented by the following equation (process variant b): The alcoholates of 3-hydroxytetrahydropyran derivatives to be used as starting materials for process variant (a) are generally defined by formula (II). In this formula, R1 to R7 preferably represent those radicals which have already been mentioned as preferred for the radicals in question in connection with the description of the compounds of the formula (I).

M preferably represents the alkali metals sodium and potassium as well the alkaline earth metals magnesium and calcium (1 equivalent each).

The alcoholates of the formula (II) are known or can be reduced known methods. They can be obtained, for example, by using the corresponding 3-Hydroxytetrahydropyran derivatives with suitable strong bases, such as Alkali or alkaline earth amides, hydrides or hydroxides, in an indifferent one Reacts solvent.

The 3-hydroxytetrahydropyran derivatives mentioned are also known or can be produced by known methods (compare e.g. Houben Weyl, Methods of Organic Chemistry, Volume 6/4; and Synthesis 1977, 578).

As examples of the 3-hydroxytetrahydropyran derivatives, which according to the invention alcoholates of the formula (II) to be used as starting materials are based, may be mentioned: 3-hydroxy-tetrahydropyran 3-hydroxy-2-methoxy-tetrahydropyran 3-hydroxy-2-ethoxy-tetrahydropyran 3-hydroxy-2-methoxyethoxy-tetrahydropyran 3-hydroxy-6-methoxy-tetrahydropyran 3-hydroxy-6-ethoxy-tetrahydropyran ) -Hydroxy-6-isocropoxy-3-methyl-tetrahydropyran 3-ethyl-hydroxy-6-isopropoxy-tetrahydropyran 3-ethyl-3-hydroxy-6-isopropoxy-2-methoxy-tetrahydropyran 3-hydroxy-6-phenyl-tetrahydropyran 3-Hydroxy-2-methoxy-6-phenyl-tetrahydropyran The continued for the process variant (A) compounds to be used as starting materials are represented by the formula (III) generally defined. In this formula, R preferably represents those radicals those in connection with the description of the compounds of formula (I) for the relevant remainder have already been mentioned as preferred.

The starting materials of the formula (III) are generally known compounds of organic chemistry. As 3elsDiele are mentioned: Benzyl chloride, benzyl bromide, Benzyl mesylate, benzyl tosylate, 2-fluorobenzyl bromide, 3-fluorobenzyl bromide, 4-fluorobenzyl bromide, 2-chlorobenzyl chloride, 3-chlorobenzyl chloride, 4-chlorobenzyl chloride, 2-bromobenzyl chloride, 3-bromobenzyl chloride, 4-bromobenzyl chloride, 2-methylbenzyl chloride, 3-methylbenzyl chloride, 4-methylbenzyl chloride, 2-methoxybenzyl chloride, 3-methoxybenzyl chloride, 4-methoxybenzyl chloride, 2-trifluoromethylbenzyl chloride, 3-trifluoromethylbenzyl chloride, 4-trifluoromethylbenzyl chloride, 4-phenylbenz-y'-chloride, 2,6-difluorobenzyl chloride, 2,6-dichlorobenzyl chloride, 2,4-dichlorobenzyl chloride, 3,4-dichlorobenzyl chloride, 2,5-dichlorobenzyl chloride, 2,6-dimethylbenzyl chloride, 2,4-dimethylbenzyl bromide, 3,4-dimethylbenzyl chloride, 2,3-dimethylbenzyl chloride, 3,4-dioxomethylene benzyl chloride, 2,6-chlorofluorobenzyl chloride, 2-fluoro-5-chlorobenzyl bromide, 2-fluoro-4-chlorobenzyl bromide, n-chloro-4-fluorobenzylbroid, 3,4-tetramethylene benzyl chloride, 2-methyl-6-chlorobenzyl chloride, 2-methyl-6- fluorobenzyl chloride, 2-fluoro-3-methylbenzyl chloride, 2-fluoro-4-methylbenzyl chloride, 2-fluoro-5-methylbenzyl chloride, 2-methyl-3-chlorobenzyl chloride, 2-methyl-4-chlorobenzyl chloride, 2-methyl-5-chlorobenzyl chloride, 2,4,5-trichlorobenzyl bromide and 2,4,6-trichlorobenzyl bromide.

Those to be used as starting materials for process variant (b) Pentanediols are generally defined by the formula (IV). Stand in this formula R and R'bis R7 for those radicals that are used in connection with the description of the Compounds of the formula (I) have already been mentioned as preferred for the radicals in question became.

The pentanediols of the formula (IV) are known or can be used known methods. It is obtained, for example, by converting from a c-hydroxy-glutaric acid ester and a benzyl halide in the presence of silver oxide produces the ether and this then in the presence of an inert solvent such as diethyl ether at 0 bis 500C reduced with complex metal hydrides.

Examples of starting materials of the formula (IV) are: 2-benzyloxypentane-1,5-diol 2- (2-fluorobenzyloxy) pentane-l, 5-diol 2- (2-fluorobenzyloxy) -3-methyl-1,5-diol 2- (2-fluorobenzyloxy) -2, 3-dimethyl-1,5-diol 2- (2-methylbenzyloxy) -pentane-1,5-diol For the implementation according to the invention according to process variant (a) come as diluents preferably inert organic solvents. These preferably include Ethers such as diethyl ether, tetrahydrofuran or dioxane, aromatic hydrocarbons, such as benzene or toluene, in some cases also chlorinated hydrocarbons, such as chloroform, methylene chloride or carbon tetrachloride.

The reaction temperatures can in process variant (a) n can be varied over a larger area. Generally one works between 0 and 1200C, preferably at 20 to 1100c.

When carrying out process variant (a) according to the invention one works preferably in molar amounts. But it is also possible to use the alcoholate of the formula (II) or the compound of the formula (III) in excess of up to 1 mol to use. To isolate the end products, the reaction mixture is mixed with water added, the organic phase separated and processed in the usual way and cleaned. In individual cases & .s end product can also be used directly after the solvent be distilled off from the reaction mixture.

According to a preferred embodiment, the procedure is expediently as follows: that one starts from a 3-hydroxy-tetrahydropyran derivative, the latter in one suitable inert solvent by means of alkali metal hydride or amide into the alkali metal alcoholate of the formula (II) converted, and the latter without isolation immediately with a compound of the formula (III) and thus the compounds of the formula according to the invention (I) received in one operation. The compound of the formula (III) can also be added to the reaction mixture before the alcoholate is prepared.

According to a further preferred embodiment, expediently the preparation of the alcohol of the formula (II) and the reaction according to the invention according to method (a) in a two-phase system, such as aqueous sodium or potassium hydroxide solution / toluene or methylene chloride, with the addition of a phase transfer catalyst, such as, for example Ammonium compounds.

For the implementation according to the invention according to process variant (b) come also inert organic solvents, such as ethers and aromatic solvents, as diluents Hydrocarbons or chlorinated hydrocarbons are possible. The inventive However, reaction according to process variant (b) is preferably carried out without a solvent carried out.

The reaction according to the invention according to process variant (b) is carried out in Done in the presence of an acidic catalyst. One can use all of them commonly use inorganic and organic acidic catalysts.

These preferably include organic acids, such as p-toluenesulfonic acid, inorganic acids such as hydrochloric acid and sulfuric acid, and metal halides such as Aluminum chloride.

The reaction temperatures can in process variant (b) in can be varied over a larger area. Generally one works between 80 and 2500C, preferably between about 100 and 220 ° C.

To isolate the end products, process variant (b) the reaction mixture in vacuo, distilled and then the water in the usual way Way separated.

The compounds of the formula (I) according to the invention can optionally exist in different geometric isomers in different proportions may arise. In addition, they are each present as optical isomers. All Isomers are the subject of the invention The inventive Active ingredients influence plant growth and can therefore be used as defoliants, Desiccants, haulm killers, sprout inhibitors and especially as weed killers be used. Weeds in the broadest sense are all plants who grow up in places where they are undesirable. Whether the substances according to the invention Acting as total or selective herbicides depends essentially on the type of herb used Amount aL.

The active compounds according to the invention can be used, for example, in the following plants earth used: dicot weeds of the genera: Sinapis, Lepidium, Galium, Stellaria, Natricaria, Anthemis, Galinsoga, Chenopodium, Urtica, Senecio, Amaranthus, Portulaca, Xanthium, Convolvulus, Ipomoea, Polygonum, Sesbania, Ambrosia, Cirsium, Carduus, Sonchus, Solanum, Rorippa, Rotala, Lindernia, Lamium, Veronica, Abutilon, Emex, Datura, Viola, Galeopsis, Papaver, Centaurea.

Dicot cultures of the genera: Gossypium, Glycine, Beta, Daucus, Fhaseolus, Pisum, Solanum, Linum, Ipomoea, Vicia, Nicotiana, Lycopersicon, Arachis, Brassica, Lactuca, Cucumis, Cuburbita.

Monocot weeds of the genera: Echinochloa, Setaria, Panicum, Digitaria, Phleum, Poa, Festuca, Eleusine, Brachiaria, Lolium, Bromus, Avena, Cyperus, Sorghum, Agropyron, Cynodon, MonocLDria, Flmbristylis, Sagittaria, Eleocharis, Scirpus, PaspaLum, Ischaemum, Sphenoclea, Dectyloctenium, Agrostis, Alopecurus, Apera.

Monocot cultures of the genera: Oryza, Zea, Triticum, Hordeum, Avena, Secale, Sorghum, Panicum, Saccharum, Ananas, Asparagus, Allium.

However, the use of the active ingredients according to the invention is by no means limited to these genera, but extends in the same way to other plants.

The compounds are suitable depending on the concentration for total weed control e.g. on industrial and rail systems and on paths and Places with and without trees. Likewise, know the connections to weed control in permanent crops e.g. forest, ornamental wood, fruit, wine, citrus, nut, banana, Coffee, tea, rubber, palm, cocoa, berry fruit and hops plants and for selective weed control can be used in annual crops.

The active ingredients according to the invention show in particular in addition to a very good effect against grass-like weeds also good herbicidal effect on broad-leaved ones Weeds. A selective use of the active ingredients according to the invention is possible, preferably in corn, peanuts, beets, soybeans, cotton, rice, rapeseed and vegetables.

With the active ingredients according to the invention it is - in contrast to the known Chloracetanlliden - possible, lopecurus or Poa annua simultaneously with other grass weeds, e.g. Digitaria, Echinochloa, Panicum and / or Setaria in the above Fight cultures.

The active ingredients can be converted into the usual formulations, such as solutions, emulsions, spray powders, suspensions, powders, dusts, pastes, soluble powders, granulates, suspension-emulsion concentrates, active ingredient-impregnated Natural and synthetic materials, fine encapsulation in polymer.

Fabrics.

These formulations are prepared in a known manner, for example by Mixing the active ingredients with extenders, i.e. liquid solvents and / or solid carriers, optionally with the use of surface-active agents, that is, emulsifiers and / or dispersants and / or foam-generating agents.

Means. In the case of using water as an extender, you can e.g. organic solvents can also be used as auxiliary solvents. as liquid solvents are essentially possible: aromatics, such as xylene, toluene, or alkylnaphthalenes, chlorinated aromatics or chlorinated aliphatic hydrocarbons, such as chlorobenzenes, chloroethylenes or methylene chloride, aliphatic hydrocarbons, such as cyclohexane or paraffins, e.g. petroleum fractions, alcohols such as butanol or Glycol and their ethers and esters, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone or CyclanexaMn, strongly polar solvents such as dimethylformamide and dimethyl sulfoxide, as well as water.

The following can be used as solid carriers: e.g. natural rock flour, such as kaolins, clays, talc, chalk, quartz, attapulgite, methyl orillonite or diatomaceous earth and synthetic minerals such as highly dispersed silica, aluminum oxide and the like Silicates; as solid carrier materials for granulates are possible: e.g.

broken and fractionated natural rocks wia. Calcite, Marble, pumice, sepiolite, dolomite and synthetic granules made from inorganic and organic flours as well as granules made of organic material such as sawdust, coconut shells, Corn on the cob and tobacco stalks; come as emulsifying and / or foam-producing agents in question; e.g. non-ionic and anionic emulsifiers, such as polyoxyethylene fatty acid esters, Polyoxyethylene fatty alcohol ethers, e.g. alkylaryl polyglycol ethers, alkyl sulfonates, Alkyl sulfates, aryl sulfonates and protein hydrolysates; come as a dispersant in question: e.g. lignin sulphite waste liquors and methyl cellulose.

Adhesives such as carboxymethyl cellulose, natural and synthetic powdery, granular or latex-like polymers are used such as gum arabic, polyvinyl alcohol, polyvinyl acetate.

Dyes such as inorganic pigments, e.g.

Iron oxide, 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 be used.

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

The active compounds according to the invention can be used as such or in their formulations can also be used in a mixture with known herbicides for weed control, finished formulation or tank mixing is possible. Also a mix with others known active ingredients, such as fungicides, insecticides, acaricides, nematicides, protective substances against bird damage, growth substances, plant nutrients and soil structure improvers is possible.

The active ingredients can be used as such, in the form of their formulations or the use forms prepared therefrom by further thinning, such as ready-to-use Solutions, suspensions, emulsions, powders, pastes and granulates can be used. It is used in the usual way, e.g. by watering, squirting, atomizing, Sprinkle.

The active ingredients according to the invention can both before and after Emergence of the plants are applied.

The application is preferably before the emergence of the plants, that is in the pre-emergence procedure.

They can also be incorporated into the soil before sowing.

The amount of active ingredient used can fluctuate over a wide range. It essentially depends on the M't of the desired effect. In general, the application rates are between 0.1 and 10 kg of active ingredient per ha, preferably between 0.1 and 5 kg / ha. Preparation examples Example 1 (Method a) 2C, 4g (0.2 mol) of 3-hydroxypyran and 1 ml of benzyl-dimethyldodecyl-dimethylammonium chloride are dissolved in a 2-phase mixture of 100 ml of 50% potassium hydroxide solution and 100 ml of methylene chloride and at OOC with stirring with 37.8 g (0.2 mol) of o-fluorobenzyl chloride were added. The temperature is allowed to rise to 250 ° C. and the mixture is stirred at this temperature for 12 hours. The organic phase is then separated off and the water phase is extracted three times with 50 μl of methylene chloride each time. The combined organic phases are washed twice with 30 ml of water, dried over sodium sulfate and concentrated by distilling off the solvent in vacuo.

The residue is distilled in a high vacuum. 34.2 g (81 % of theory) 3- (2-Pluorbenzyloxy) -tetrahydropyran with a boiling point of 95 ° C / O, 1 Torr.

example (Method a) In 200 ml of absolute 3ioxane, 4.5 g of sodium hydride are dispersed under a nitrogen atmosphere, 18.5 g (0.1 mol) of o-methylbenzyl bromide are added and 10.2 g (0.1 mol) of 3-hydroxypyran are added dropwise with constant stirring added. The mixture is then heated to boiling with stirring and left to react for 2 hours. It is cooled, 5 ml of methanol are carefully added dropwise and the mixture is concentrated by distilling off the solvent in vacuo. The residue is carefully hydrolyzed on ice water, then extracted three times with 100 ml of ether each time, the organic phases are combined, washed neutral with water and dried over sodium sulfate. The solution is filtered and concentrated by distilling off the solvent in vacuo. The residue is distilled in a high vacuum.

14.3 g (69.4% of theory) of 3- (2-methylbenzyloxy) tetrahydropyran are obtained of boiling point 990C / 0.1 Torr.

Example 3 (Method a) In 200 ml of absolute dioxane, 4.5 g of sodium hydride are dispersed under a nitrogen atmosphere, 19.56 (0.1 mol) of 2,6-dichlorobenzyl chloride are added and 13.2 g (0.1 mol) of 2- Methoxy-3-hydroxytetrahydropyran added. The mixture is then heated to boiling with stirring and left to react for 2 hours.

It is cooled, 5 ml of methanol are carefully added dropwise and the mixture is concentrated Distilling off the solvent in vacuo. The residue is hydrolyzed carefully on ice water, carefully extracted three times with 100 ml of ether, combined the organic phases, washes with Water neutral and dries over sodium sulfate. The solution is filtered and removed by distilling off the solvent concentrated in vacuo. The residue is distilled in a high vacuum. 23.9 g are obtained (82.0% of theory) 3- (2,6-dichlorobenzyloxy) -2-methoxy-tetrahydropyran of boiling point 123 ° C / 0.2 torr.

Example 4 (Method a) 29.2 g (0.2 mol) of 2-ethoxy-5-hydroxy-tetrahydropyran and 1 ml of benzyl-dodecyl-dimethylammonium chloride are dissolved in a 2-phase mixture of 100 ml of 50% potassium hydroxide solution and 100 ml of methylene chloride and in 29.2 g (0.2 mol) of o-methylbenzyl chloride are added to OOC with stirring. The temperature is allowed to rise to 250 ° C. and the mixture is stirred at this temperature for 12 hours. The organic phase is then separated off and the aqueous phase is extracted three times with 50 ml of methylene chloride each time. The combined organic phases are washed twice with 30 ml of water each time, dried over sodium sulfate and concentrated by distilling off the solvent in vacuo. The residue is distilled in a high vacuum. 46.3 g (92.6% of theory) of 2-ethoxy-5- (2-methylbenzyloxy) tetrahydropyran with a boiling point of 100C / 0.4 torr are obtained.

In an analogous manner, those listed in the table below are listed Get connections.

Table 1 E.g. Kp (OC) / No. RR R2 R3 R4 R5 R6 R7 mmIig-SUule TF 5 HHHHHH OCH3 93 / 0.1 6 t HHHHMH OC2H5 103 / 0.3 CHÖG 7 CH2O HHHHHH OC2H41 ° 144 / 0.5 OH3 8 t H EI HHHH OC2H40 126 / 0.3 CH3 HOHHHHHH OCH, 108 / 0.5 10 C t HH HHHH OCH3 109 / 0.3 11 Br HHHHHH OCH3 121 / 0.3 12 1 - OHHHHHH OCH3 109 / 0.5 13 HHH es OC2H5 HHH 110 / 0.4 14 C t HHH OQH5 HHH 146 / 0.5 Examples of use In the following example, the compound given below is used as a comparison substance: 2-Ethyl-6-methyl-N- (1'-methyl-2'-methoxy-ethyl) -chloroacetanilide Example A Pre-emergence test solvent: 5 parts by weight. Acetone emulsifier: 1 part by weight of alkylaryl polyglycol ether To produce an appropriate preparation of active ingredient, 1 part by weight of active ingredient is mixed with the stated amount of solvent, the stated amount of emulsifier is added and the concentrate is diluted with water to the desired concentration.

Seeds of the test plants are sown in normal soil and after Doused with the active ingredient preparation for 24 hours.

The amount of water per unit area is expediently kept constant. The concentration of the active substance in the preparation does not matter, it is decisive is only the amount of active ingredient applied per unit area. After three weeks it will the degree of damage to the plants rated in 6 damage in comparison to development the untreated control. It means: 0% = no effect (like untreated Control) 100 6 = total destruction In this test, for example, the following compounds show of the production examples an 'excellent effect, which is the effect of the the prior art known compound (A) of the same direction of action clearly is superior: 1, 2, 5, 6, 8.

Claims (7)

Claims 1retrahydropyranether derivatives of the general formula in which R is optionally substituted phenyl, R1 is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl or optionally substituted phenyl, R2 is hydrogen or alkyl, R3 is hydrogen or alkyl, R4 to R7 are identical or different and are hydrogen , Alkyl, alkoxy, alkoxyalkyl, alkoxyalkoxy, haloalkyl or optionally substituted phenyl, and R4 and R5, R6 and R7 as well as R4 and R6 each together represent an alkylene bridge, 2) Process for the preparation of tetrahydropyran ether derivatives of the formula (I), characterized in that (a) alcoholates of 3-hydroxytetrahydropyran derivatives of the formula in which R1 to R7 have the meaning given above, and M is an alkali or alkaline earth metal, with a compound of the formula Y-CH2-R (III) in which R has the meaning given above, and Y is halogen, in particular chlorine or bromine, the mesylate or tosylate radical, is reacted in the presence of a diluent, or (b) pentanediols of the formula in which R and R1 to R7 have the meaning given above, heated in the presence of an acidic catalyst and optionally in the presence of a diluent. 3) Herbicidal agents, characterized by a content of tetrahydropyran ether derivatives according to claim 1. 4) Method of controlling unwanted plant growth, thereby characterized in that one tetrahydropyran ether derivatives according to claim 1 to the undesired Plants or their habitat. 5) Use of tetrahydropyran ether derivatives according to claim 1 to combat unwanted plant growth. 2) Process for the preparation of tetrahydropyran ether derivatives of the formula (I), characterized in that (a) alcoholates of 3-hydroxytrahydropyran derivatives of the formula in which R1 to R7 have the meaning given above, and M is an alkyl or alkaline earth metal, with a compound of the formula Y -CH2-R (III) in which R has the meaning given above, and Y is halogen, in particular chlorine or bromine, the mesylate or tosylate radical, is reacted in the presence of a diluent, or that (b) pentanediols of the formula in which R and R1 to R7 have the meaning given above, heated in the presence of an acidic catalyst and optionally in the presence of a diluent. 3) Herbicidal agents, characterized by a content of tetrahydropyran ether derivatives according to claim 1. 4) Method of controlling unwanted plant growth, thereby characterized in that one tetrahydropyran ether derivatives according to claim 1 to the undesired Plants or their habitat can act. 5) Use of tetrahydropyran ether derivatives according to claim 1 to combat unwanted plant growth. 6) Process for the preparation of herbicidal agents, characterized in that that tetrahydropyran ether derivatives according to claim 1 with extenders and / or surfactants mixed. 7) tetrahydropyran ether derivative according to claim 1 of the formula 8) tetrahydropyran ether derivative according to claim 1 of the formula 9) tetrahydropyran ether derivative according to claim 1 of the formula 10) tetrahydropyran ether derivative according to claim 1 of the formula 11) tetrahydropyran ether derivative according to claim 1 of the formula