CS219297B2 - Means for destroying the weeds and method of making the active substance - Google Patents

Abstract

The invention is concerned with herbicidally active propionic acid esters of the general formula <IMAGE> wherein R<1> represents hydrogen, C1-6 alkyl or a phenyl group, R<2> represents C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl or a phenyl group or R1 and R2 together with the carbon atom to which they are attached form a C4-10 cycloalkane ring which, if desired, can be mono-, di- or tri-substituted with C1-3 alkyl, R<3> represents a halogen atom or a trifluoromethyl or nitro group and R<4> and R<5> each represent a hydrogen or halogen atom.

Description

The present invention relates to a composition for controlling weeds, i.e. a herbicidal composition suitable for pre-emergence and post-emergence application, containing novel propionic acid esters as the active ingredient. The invention further relates to a process for the preparation of an active ingredient.

The present invention provides a weed control composition comprising at least one ester as the active ingredient. propionic acid. of formula I,

in which

^R1 is hydrogen or alkyl having 1 to 6 carbon atoms,

R ² represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, or

R 1 and R 2 together with the carbon atom to which they are attached represent a C 4 -C 10 cycloalkane ring optionally substituted with C 1 -C 3 alkyl, one, two or three times,

R ³ represents a halogen or a trifluoromethyl group and

R 4 represents hydrogen or halogen, together with an inert carrier.

According to the invention, the compounds of the general formula: I are produced by the formation of an acid salt of the formula II,

COOH

219197 (II) wherein

R ³ and R 4 are as defined for formula (I), act by a compound of formula (III),

R1R2CNOCH2X (III) wherein

R1 and ^R2 are as defined for formula I and

X is a leaving group.

The term "alkyl" of 1 to 6 or 1 to 3 carbon atoms includes, unless otherwise indicated, both straight and branched chain hydrocarbon radicals of 1 to 6 or 3 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and the like. The term "lower alkyl" refers especially to alkyl groups having 1 to 6 carbon atoms.

The terms "C 2 -C 6 alkenyl" include straight and branched alkenyl radicals of up to 6 carbon atoms such as allyl, butenyl, isobutenyl, pentenyl, isopentenyl and the like.

The term "halogen" includes fluorine, chlorine, bromine and iodine, preferably chlorine, bromine and iodine.

The cycloalkane ring preferably contains 4 to 7 carbon atoms, in particular 4 to 6 carbon atoms.

Aryl groups are in particular phenyl, which is optionally substituted by 1 to 3 lower alkyl groups, as well as naphthyl. The alkyl groups may be the same or different.

Preferred "heteroaryl groups" are pyridyl, imidazolyl, thiazolyl and thiophenyl.

Preferred compounds of formula I are those wherein R 1 is methyl or ethyl, R 2 is methyl or ethyl, R 3 is chloro or trifluoromethyl, and R 4 is hydrogen. Also preferred are compounds of formula I wherein R 1 and R 2 together with the carbon atom to which they are attached form an optionally substituted cycloalkane ring.

Particularly preferred compounds of formula I are:

{[(isopropylidenamino) oxy] methyl jester 2- {p - ((α, α-trifluoro-p-tolyl) oxy] phenoxy) propionic acid and {[(isopropylidenamino) oxy] methyl] ester

- (p - (p-chlorophenoxy) phenoxy] propionic acid.

Further examples of compounds of formula I include:

{[(isopropylideneamino) oxy] methyl] ester.

- [p- (2 ', 4' - ((d ', 4'-fluorophenoxy) phenoxy) propionic acid, {[(sec-butylideneamino) oxy] methyl ester 2- {p- ((α-β-trifluoro-) -) p-tolyl) oxy] propionic acid, {[(1-pentylhexylldenamino) oxy] methyl ester 2-β-α, α, α, α-trifluoro-p-tolyl) oxy] phenoxy] propionic acid, ([(1 3-Dimethyl-2-butylideneamino) oxy] methyl ester 2-β - [(α, α, α-tert-fluoro-pl) olyl] oxy] phenoxy] propionic acid, [[(cyclohexylideneamino) oxy] methyl) ester 2- [-- [( ^α,! TO, α-tri-fluoro-p-tolyl) oxy] fenoxyjprrpirnové acid {[(cyclopentylmethyl Hdenamino) oxy] methyljester 2- [p- [(.α, α, ¢ t tr-fluoro-p- -tolyl) oxy] propionic acid, {[(cycloheptyl lidenamiiio) oxy] methyljester 2- {p- [(α ^L, α, α-p-triflurr trlyl] oxy] fenoxyjpropirnové acid {[(isopropylideneamino) oxy] methyljester 2 - [p- (p-bromophenoxy) propionic acid as well as the (lower) alkyl-substituted derivatives of the above cyclopentylideneamino, cyclohexylideneamino and cycloheptylideneamino derivatives.

Particularly preferred are the D-forms of the compounds of the formula I and thus the D-forms of the above-mentioned compounds.

In the preparation of the compounds of formula I, the acid salt of formula II is reacted with a compound of formula III.

The term "acid salt" means, for example, an alkali metal salt such as a sodium, potassium or lithium salt, or an alkaline earth metal salt such as a magnesium, calcium or barium salt, an organic base salt such as a mono-, di- or trialkyl ammonium salt; pyrldinium salt or ammonium salt.

The term "leaving group" for X means, for example, chlorine, bromine, iodine, tosyloxy, mesyloxy, hydroxyl in free or esterified form, or any of the following groups:

where

R ⁷ , R 8 and R ⁹ , which may be the same or different, represent an alkyl group, especially having 1 to 6 carbon atoms, or two of these radicals also together form an alkylene group having 4 to 7 carbon atoms and

Y6 represents an anion, for example a chloride, bromide, iodide, hydroxyl or sulfate anion;

©, R ^{, c} Q И ^Y where

_{R 10 and R 11,} which may be the same or different from each other, represent an alkyl group, especially having 1 to 6 carbon atoms, and Y 6 is as defined above;

(O) _n

II

S = R1-2 where is

R ^{12 is} lower alkyl, aryl or heteroaryl and n is 1 or 2.

The esterification of the acid of formula II with a compound of formula III is preferably carried out in a suitable inert solvent, at about -10 to 220 ^° C, preferably at room temperature or at elevated temperature. A particularly preferred temperature range is between 20 and 70 ° C. The reaction is carried out, for example, in the presence of an inert solvent such as benzene, toluene, petroleum ether, dimethylformamide, tetrahydrofuran, acetonitride, N-methyl-2-pyrrolidone, tetramethylurea, dimethoxyethane, diglycol dimethyl ether or hexamethylphosphoric triamide.

The compounds of formula I also include optical isomers, since they contain one asymmetric carbon atom in the α-position to the carbonyl group. Other asymmetric carbon atoms may contain ester components. The racemic compounds may optionally be resolved into dextrorotatory and levorotatory using known methods. Such procedures are described, for example, in Industrial and Engineering Chemistry 69 (8) 12-28. Isomers and racemic mixtures all have herbicidal activity, but the degree of this activity is different. The D-isomers have the highest activity, followed by racemic mixtures and then the L-isomers. In connection with these experiments, it has been found that, for example, in a particular experiment set-up, the D-isomer of 2-β- [(α, α, α-trifluoro-p-tolyl) oxy] phenoxy] propionic acid | greater efficiency than the racemic mixture.

Isomers can also be prepared by synthesis from the corresponding optically active starting materials. As mentioned above, the D-isomers of the compounds of formula I are particularly preferred and the corresponding starting materials are also preferred.

Due to the nitrogen-carbon double bond in the group

Ri /

—N = C \

R ² were obtained in each case two geometric isomers (if and ^R2 have different meanings) which are referred to as syn- and anti-form. In certain cases, such isomers are isolated. These isomers are also within the scope of the invention.

The weed control composition according to the invention contains as active ingredient one or more compounds of the formula I as defined above. The herbicidal mixture expediently comprises at least one of the following inert materials: carriers, wetting agents, inert diluents and solvents.

The herbicidal compositions according to the invention, used pre-emergence and post-emergence, are particularly suitable for combating grassy weeds, in particular Alopecurus myosuroides and prosaic species, such as Echinochloa crus-gallij, Setaria fabillare and Panicum capilla. in cereal crops, especially in barley, oat and wheat crops, as well as in rice, cotton, soybean, sugar beet and vegetable crops, the herbicidal compositions according to the invention are particularly suitable for controlling grass weeds in sugar beet crops. (isopropylideneamino-oxymethyl) -ester 2- | pp - [(',', '- trifluoro-p-tolyl] oxy] phenoxy' propionic acid at a concentration of 1.25 kg / ha and sufficient activity against grass weeds without damaging the sugar beet culture In general, a concentration of 0.1 to 6 kg / ha, preferably 0.6 to 2.0 kg / ha, particularly preferably 1 to 1.5 kg / ha, is sufficient to achieve the of compounds of the formula I of the desired herbicidal effect.

In the case where R ³ is a trifluoromethyl group, these compounds can only be used conditionally in the cultivation of cereals, since there is some phytotoxicity. However, these compounds are particularly suitable for combating grass weeds in rice, cotton, soy, sugar beet and vegetable crops.

The compounds of formula I are generally water insoluble and can be formulated according to one of the methods customary for insoluble compounds.

If desired, the compounds of formula I may be dissolved in a water-immiscible solvent, such as a high boiling hydrocarbon, which conveniently contains dissolved emulsifiers, so that when added to water it acts as a self-emulsifiable oil.

The compounds of formula I may also be mixed with a wetting agent and, if appropriate, an inert diluent to form a wettable powder that is water-soluble or dispersible, or may be mixed with inert diluents to form a solid or powdered product.

The inert diluents with which the compounds of formula I may be applied are solid inert media, including powdery or finely dispersed solids such as clay, sand, talc, mica, fertilizers and the like, and such products may be present either in powder form or as larger particle size materials.

The surfactants may be anionic compounds such as soaps, sulfuric acid fatty alcohol esters such as dodecyl sodium sulfate, actadecyl sodium sulfate and cetyl sodium sulfate, alkylarylsulfonates such as alkylbenzenesulfonates or butylnaphthalenesulfonates, more complex sulfonates, such as the oleic acid succinate or N-acid condensation products.

The surfactants may also be nonionic surfactants, such as. condensation products of fatty acids, fatty alcohols or phenols, substituted with fatty substituents, with ethylene oxide or esters and ethers of sugars or polyhydric alcohols with fatty acids, or products obtained from the latter by condensation with ethylene oxide, or products known as block polymers of ethylene oxide and propylene oxide. The surfactants may also be cationic agents such as cetyltrimethylammonium bromide and the like.

The herbicidal mixture may also be in the form of an aerosol, whereby in addition to the propellant, which is a suitably polyhalogenated alkane, such as dichlorodifluoromethane, a co-solvent and a wetting agent are used.

In addition to the compounds of formula I, the herbicidal compositions according to the invention may contain synergists and other active substances, for example insecticides, acaricides, bactericides, other herbicides, fungicides, plant growth regulators and fertilizers. Such combination means are suitable for enhancing the efficiency or broadening the spectrum of activity.

In various fields of application, the compounds of formula I may be used in different amounts.

The weed control compositions of the present invention may be provided in a form suitable for storage and transportation. Such forms may contain, for example, 2 to 90% by weight of one or more active compounds of the formula I. These forms may then be diluted with the same or different carriers up to a concentration which is suitable for practical use. In useful compositions, the concentration of active ingredient may then be from 0.05 to 80% by weight. However, the concentration of active ingredient may also be less or greater. Depending on the intended use, the active compound concentration is preferably from 2 to 8% or 50 to 80% by weight.

The starting materials of formulas II and III belong to the known class of substances.

The following examples serve to illustrate the invention in more detail. All temperatures are in degrees Celsius.

I. Production of active substances · formula I:

Example 1

A solution of 10 g (0.0307 mol) of D-2- {p - [(«,«, «

-trifluoro-p-tolyl) oxy] phenoxy] propionic acid in 100 ml of dimethylformamide was added dropwise to a suspension of 1.5 g of a 55% (0.0307 mol) sodium hydride dispersion in 20 ml of dimethylformamide with stirring. After the addition, the reaction mixture was further stirred at room temperature until evolution of hydrogen ceased. The reaction mixture is then stirred for a further 15 minutes and 15 g (0.048 mol) of N- [(isopropylideneamino) oxymethyl] -N-methylpiperidine iodide and 0.5 g of 15-crown-5 polyethylene ether-crown derivative with a 15-membered ring containing 5 oxygen atoms). After stirring at 110 ° C for 2 hours, the reaction mixture is poured onto 500 ml of water and extracted three times with 300 ml of ethyl acetate each time. The entire ethyl acetate solution is then washed twice with 200 ml of water each time and evaporated and the residue is recrystallized from a mixture of diethyl ether and n-hexane. 8.0 g of D-2- {p [(α, -α, N-trifluoro-p-tolyl) oxy] -phenoxy] -propionic acid [(isopropylideneamino) -oxy] methyl ester, melting at 85-86 ° C, were obtained. ;

[α] D ²⁰ + 11.3 ° (c = 1.2% in CHCl 3).

The following compounds were obtained in an analogous manner using the corresponding starting materials:

{- (isopropylideneamino) oxy is obtained from sodium salt of 2- (p - [(α, α, α-trilluoro-p-tolyl) oxy] -phenoxy] propionic acid and N - [(isopropylideneamino) oxymethyl] -N-methylpiperidinium iodide; 2- {β- [ω-α-[-fluoro-β-tolyl] oxy] phenoxy] propionic acid methyl ester, m.p. 76-77 °, from D-2-p- (p-chloro) sodium salt enoxy) phenoxy] -propionic acid and N - [(isopropylideneamino) oxymethyl] -N-methylpiperldinium iodide affords D- 2- [p- (p-chlorophenoxy) phenoxy] propionic acid {[(isopropylideneamino) oxy] methyl ester, nD ²⁰ 1.5480 [.alpha @ ²² + 13.58 DEG (c = 1.93 ° / s, chloroform), from the sodium salt of 2- [p- (o, p-dichlorophenoxy) phenoxy] -propionic acid and N- [ (isopropylidenamino) oxymethyl] -N-methylpiperidinium iodide gave 2- [p- (o, p-dichlorophenoxy) phenoxy] propionic acid {[(isopropylidenamino) oxy] methyl] ester, ηβ20 1,5557, from D-2- sodium salt -p- (p-bromo enoxy) phenoxy] propionic acid and N - [(isopropylideneamino) oxymethyl] -IN-methylpfp erfdfnium iodide to yield D-2- [p- (p-bromophenoxy) phenoxy] propionic acid {[(isopropylideneamino) oxy] methyl] ester, nD20 1.5598; [Α] D ²⁰ + 11.92 ° (c = 1.15% in chloroform, from D-2- [p- (p-iodo-ethoxy) -phenoxy] -propionic acid sodium salt and N - [[isopropyl-denamino) oxymethyl] - N-methylpiperidinium iodide affords D-2- [p- (p-iodophenoxy) phenoxy] propionic acid {[(isopropylideneamino) oxy] methyl] ester, m.p. 40-43 °; [α] ²⁰ + 8.80 ° (c = 0.90% in chloroform), from sodium D-2- (p- [α, α, α-trifluoro-p-tolyl) oxy] phenoxy) propionic acid acids and N-

- [(cyclopentylideneamino) oxymethyl] -N-methylpiperidinium iodide yields {[(cyclopentylideneamino) oxy] methyl] ester D-2- [p - [(a *, α, α-trifluoro-β-tolyl) oxy] phenoxy] propionic acid acids, mp 43-45 °; [α] D ²² + 7.52 ° (c = 2.28% in chloroform), from D-2- {p - [(α, α, α-trifluoro-p-tolyl) oxy] phenoxy] propionic acid sodium salt acid and N [(cyclohexylideneamino) oxymethyl] -N-methylpiperidinium iodide gave {[(cyclohexylideneamino) oxy] methyl] ester D-2- (p - [(α, α, α-trifluoro-p-tolyl) oxy] phenoxy {propionic acid mp 71-73 °; [α] D ²² H-5.55 ° (c = 1.49% in chloroform), of sodium Ο-2- {ρ - [(α ·, α, α4πί1υθΓ-ρ) -flylyl) oxy] phenoxy} propionic acid and N-

- [(cycloheptylideneamino) oxymethyl] -N-methylpiperidinium iodide affords D- 2- [p - [(α ', α, α-difluoro-p-tolyl) oxy] phenoxy] propionic acid {[(cycloheptylideneamino) oxy] methyl] ester, about 30 °; [Α] D ²² + 6.00 ° (c = 1.96 in chloroform), from D-2-β - [(trans, α, α-trifluoro-p-tolyl) oxy] phenoxy [propionic acid sodium salt and N [(3,3,5-trimethylcyclohexylideneamino) oxymethyl] -N-methylpiperidinium iodide gives {[(3,3,5-trimethylcyclohexylideneamino) oxy] methyl] (ester D-2-) p - [(α, β, α-trifluoro) p-tolyl) oxy] fenoxyjpropionové acid, n _o ²⁰ 1.5062; [a] _D ²² + 6.86 ° (c = 2.73% in chloroform); from D-2- [p - [( α, α, α-trifluoro-p-tolyl) oxyphenoxy] -propionic acid and N - [(sec-butylideneamino) oxymethyl] -N-methylpiperidinium iodide are obtained ([(sec-butylideneamino) oxy] methyl] ester D-2- (p- [(α, οί, α-trifluoro-p-tolyl) oxy] phenoxy) propionic acid, melting point 38-40 °, [α] ²² D-10.34 ° (c = 2.36% in chloroform), from the sodium salt of D-2- (p - [(α, α, α-trifluoro-p-tolyl) oxy] phenoxy | propionic acid and N - [(1-pentylhexylenenamino) oxymethyl] -N-tetramethylpiperidinium iodide is obtained ([(1-Pentylhexylideneamino) oxy] methyl) ester D-2- (p - [(α, α, ω-trifluoro-p -tolyloxy-phenoxy) -propionic acid; n _D ²⁰ 1.4913; [<T] _D ²² + 11.71 ° (c = 3.27% in chloroform); from D-2- (p- [(aaaf-trifluoro-p-tolyl) oxy] phenoxy propionic acid and N- [(1,3-dimethyl-2-butenylideneamino) oxymethyl] N-methylpiperidinium iodide gives {[(1,3-dimethyl-2-butenylideneamino) oxy] methyl ester D-2- [p - [(a, fz, α-trifluoro) -p-tolyl) oxy (phenoxy) propionic acid, m.p. 52-65 °; [α] _D ²² -5.75 ° (c = 0.78% in chloroform).

II. Production of starting materials

Example 2

To 100 ml of a 36% formaldehyde solution is added dropwise 100 ml of piperidine at 10 ° while cooling, and then 73 g of acetonoxime and 75 g of potassium carbonate are added. The reaction mixture was stirred overnight at room temperature, then taken up in ethyl acetate and the aqueous phase separated. The organic phase is evaporated, taken up in acetone, and 65 ml of methyl iodide is added dropwise with cooling, and the product crystallizes slowly. After a further 10 hours, the product was filtered off. 291 g of N- [(isopropylideneamino) oxymethyl] -N-methylpiperidinium iodide are obtained, m.p. 132 DEG-133 DEG.

Other N- [(alkylideneamino) oxymethyl] -N-methylpiperidinium iodides as well as the corresponding alkenylideneamino and cycloalkylideneamino derivatives are prepared in an analogous manner.

III. Examples illustrating the composition and preparation of compositions

Example 3

In order to produce an emulsifiable concentrate, the following components are mixed together:

compound of formula I500 g condensation product of alkylphenol and a mixture of ethylene oxide and calcium salt of dodecylbenzenesulfonic acid100 g epoxidized soybean oil with an oxirane oxygen content of about 6% 25 g butylated hydroxytoluene10 g

This mixture was made up to 1 liter with xylene.

Example 4

An active substance, for example {[(isopropylideneamino) oxy] methyl] 2- [p - [[<, [t, t-tri -192929 fluoro-p-tolyl) oxy] phenoxy) propionic acid (referred to as Compound A in the following table) in acetone to form a 2% solution of the active ingredient. Shortly before the start of the experiment, the solution is diluted to the desired concentration of 312 g / ha in the test described. (When insoluble active ingredients are used, wettable powders are prepared which contain kaolin as an inert diluent).

IV. Tests illustrating biological efficacy

The test plants are sprayed in the greenhouse with the active ingredient in the form of compositions. A mercury vapor lamp simulates a 16-hour day. 3 weeks after spraying, the effect on plants is examined, i.e.% necrosis is determined, with 100% necrosis corresponding to complete destruction of the plant. The effects of solvents - if any - are compensated by the "Abott formula". The results of the experiment are summarized in the following table:

Table I (% necrosis) Active substance Alopecurus myosuroides Digitaria floridana Avena fatua Echinochloa crus-galli Setaria faberi AND 100 ALIGN! 100 ALIGN! 100 ALIGN! - - В - 100 ALIGN! - 100 ALIGN! 100 ALIGN! C - 100 ALIGN! - 100 ALIGN! 100 ALIGN! D - 100 ALIGN! - 100 ALIGN! 80 E - 100 ALIGN! - 100 ALIGN! 90 F - 100 ALIGN! - 100 ALIGN! 100 ALIGN! G - 100 ALIGN! - 100 ALIGN! 100 ALIGN! H - 100 ALIGN! - 100 ALIGN! 100 ALIGN! AND - 50 - 100 ALIGN! 100 ALIGN! J - 100 ALIGN! - 100 ALIGN! 90 К - 30 - 100 ALIGN! 90 L - 100 ALIGN! - · 100 ALIGN! 100 ALIGN!

A = ([(isopropylideneamino) oxy] methyl) 2- (p - [(d, a, α-trifluoromethyl-p-tolyl) oxy] phenoxy) propionic acid,

G = D-2- (p - [(α, α, α-Trifluoro-p-tolyl) oxy] phenoxy) propionic acid {[(cyclohexylideneamino) oxy] methyl} ester,

V = {[(1,3-dimethyl-2-butenylideneamino) oxy] methyl) D-2- [p - [(α, α ', α-trifluoro-p-tolyl) oxy] phenoxy) propionic acid ester,

C = {[(cyclopentylideneamino) oxy] methyl] D-2 ^J [p - [(α ', α, α-trifluoro-p-tolyl) oxy] phenoxy) propionic acid,

D = {[(sec-butylideneamino) oxy] methyl) D-2- [p - [(α, α, α-α-fluoro-p-tolyl) oxy] phenoxy) propionic acid ester,

E = {[(1-pentylhexylldenamino) oxy] methyl] D-2- (p - [(α, α-trifluoro-p-tolyl) oxy] phenoxy) propionic acid methyl ester,

F = {[(3,3,5-trimethylcyclohexylideneamino) oxy] methyl) D-2- [p - [(α, α, trif trifluoro-p-tolyl) oxy] phenoxy] propionic acid ester,

D = 2- [p - [(α, α, α-Trifluoro-p-tolyl) oxy] phenoxy] propionic acid H = [(isopropylideneamino) oxy] methyl) ester,

I = D-2- [p- (p-chlorophenoxy) phenoxy] propionic acid {[(isopropylideneamino) oxy] methyl] ester,

J = | D-2- [p- (p-bromophenoxy) phenoxy] propionic acid [(isopropylideneamino) oxy] methyl} ester,

D = 2- [p- (p-iodophenoxy) phenoxy] propionic acid, K = [[(isopropylideneaminooxy) methyl] ester,

D = 2- [p- (o-chloro-p-iodophenoxy) phenoxy] propionic acid L = {[(isopropylideneamino] oxy] methyl) ester.

Example 5% Cotton necrosis (Stoneville 7A) dose kg / ha

Table II Compound A Compound M

1,25

0.62

Composition:

active substance 250 g / liter NMO 300 g / liter Tensiofix В 7425 100 g / liter Phenylsulfonat CA 25 g / liter Shellsol AB make up to 1000 ml.

wetting agent: 0.08% nonoxynol treatment growth stage: 2 leaf stage spray liquid volume: 1000 l / ha evaluation: 10 days after treatment site: greenhouse compound A: see Example 4 compound M = methyl ester D-2- [p- ( p-trifluoromethylphenoxy] phenoxy] propionic acid

Example 6

Table III% soya bean necrosis (Hoodj

dose kg / ha Compound A 1,25 0 0.62 0 Composition: active substance 250 g / liter NMP 300 g / liter Tensiofix В 7425 100 g / liter

Phenylsulfonate CA 25 g / liter

Shellsol AB make up to 1000 ml.

Wetting agent: 0.08% Nonoxynol growth stage at treatment: 2 three-piece leaves spray liquid volume: 1000 liters / ha Evaluation: 2 weeks after treatment site: greenhouse Compound A: see Example 4.

The designations NMP, Tensiofix 7425, Phenylsulfonate CA, Shellsol AB and Nonoxynol used in Examples 5 and 6 above have the following meanings:

NMP: N-methyl-2-pyrrolidone

Tensiofix B: emulsifier consisting of 60 parts of block polymer of ethylene oxide and propylene oxide, 20 parts of branched-chain dodecylbenzenesulfonic acid calcium and 20 parts of a solvent mixture consisting of isobutanol and 10-carbon alkylbenzenes, Phenylsulfonate CA: mixture of 70 parts calcium salt branched-chain dodecylbenzenesulfonic acid and 30 parts solvent mixture of isobutanol and alkylbenzenes of 10 carbon atoms in alkyl,

Shellsol AB: solvent consisting of a mixture of alkylbenzenes of 10 carbon atoms in alkyl,

Nonoxynol: the condensation product of nonylphenol and ethylene oxide.

Claims (14)

SUBJECT OF THE INVENTION A weed control composition comprising an effective amount of at least one compound of formula (I): COOCH.ON = C ^X , ^X /? ^Z in which ^R1 is hydrogen or alkyl having 1 to 6 carbon atoms, R ² represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms, or R ¹ and R ² together with the carbon atom to which they are attached form a C 4 -C 10 cycloalkane ring which is optionally mono-, di- or trisubstituted with C 1 -C 3 alkyl, R ³ represents a halogen or a trifluoromethyl group and R ⁴ is hydrogen or halogen, and an inert carrier. 2. A composition according to claim 1, wherein the active ingredient is a compound of formula (I) wherein the cycloalkane ring of R &lt; ¹ &gt; and R &lt; ² &^gt; 3. A composition according to claim 2, characterized in that it contains as active ingredient a compound of formula I in which ^R1 represents a methyl or ethyl group and the other symbols are as defined in point 2. 4. A composition according to claim 2 or 3, wherein the active ingredient is a compound of formula (I) wherein R2 is methyl or ethyl and the other symbols are as defined in claim 2 or 3. 5. The device of any one of items 2 to 4. A compound of formula (I) wherein R3 is chloro or trifluoromethyl and the other symbols are as defined in (2) to (4). 6. The composition of any one of items 2 to 5. A compound of the formula I as active ingredient in which R4 is hydrogen and the other symbols have the meanings given in points 2 to 5. 7. A composition according to claim 2, comprising an effective amount of 2- [p - [(α, trifluoro-p-tolyl) oxy] phenoxy] propionic acid, [(isopropylideneamino) methyl] ester, and inert. carrier substance. 8. A composition according to claim 2 comprising an effective amount of 2- [p- (p-chlorophenoxy) phenoxy] propionic acid {[(isopropylideneamino) oxy] methyl ester and an inert carrier. 9. A composition according to claim 2 comprising an effective amount of at least one of the compounds selected from the group consisting of [[(isopropylideneamino) oxy] methyl] ester D-2- [p- [(α, α, β-triffuoro-p- tolyl) oxy] phenoxy] propionic acid, [[(isopropylideneamino) oxy] methyl] D-2- [p- (p-chlorophenoxy) phenoxy] propionic acid methyl ester, {[(isopropylideneamino) oxy] methyl] ester, 2- (p- (o , p-dichlorophenoxy) phenoxy] propionic acid, [[(isopropylidenamino] oxy] methyl] D-2- (p- (p-bromophenoxy) phenoxy] propionic acid, [[(cyclopentylideneamino) oxy] methyl] D-2- [p- [(α, α ^| α-trif] lorip-olyl) oxy] phenoxy] propionic acid, [[(cyclohexylideneamino) oxy] methyl ester D-2- [p- [(α, α, N-trif] lloг-p] -tolyl) oxy] phenoxy] propionic acid, [[(sec-butylideneamino) oxy] methyl ester D-2- {p- [α, ω, trifluoro-p-tolyl) oxy] phenoxy] propionic acid and {[(1-pentylhoxylideneamino)] oxy] methyl ester D-2- {p - [(n, α, α-trifluoro-p-tolyl) oxy] phenoxy propionic acids, and an inert carrier. 10. A composition according to claim 1 comprising an effective amount of at least one compound selected from the group consisting of {[(isopropylideneamino) oxy] methyl] -ester D-2- [p-iodophenoxy) phenoxy] propionic acid, {[(3,3 , 5 - ηηιβΏιγ1 · (: γ1 <1οΤΐθχγ1ί <1θη3ΐηίηο) oxy] methyl ester of D-2- [p- [(α, α, α-trifluoro-p-tolyl) oxy] phenoxy} propionic acid and {[(1 ^ D-2- [beta, [alpha, [alpha], [alpha] -trifluoro-p-tolyl) oxy] phenoxy] propionic acid, -dimethyl-4-butenylideneaminooxy] methyl ester, and an inert carrier. 11. A composition according to claim 1, wherein the active ingredient is a compound or compounds of formula I. which are used in the form of D-isomers. Composition according to one of Claims 2 to 6, characterized in that it contains, as active ingredient, a compound or compounds of formula I which are used in the form of D-somers. 13. A process for the preparation of an active ingredient as defined in claim 1, which comprises: COOH di) in which R 3 and R 4 have the meanings given in formula (I), act by a compound of formula (III), R 2 R 2 CNOCH 2 X (III) wherein R1 and R2 have the meanings given in formula Ia X is a leaving group. 14. The method according to item 131, characterized in that as the starting material used is a compound of formula II wherein R ¹ is hydrogen or alkyl having 1 to 6 carbon atoms and R2 represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group C 2 -C 6, or wherein R 1 and R 2 together with the carbon atom to which they are attached form a C 4 -C 6 cycloalkane ring optionally mono-, di- or trisubstituted with C 1 -C 3 alkyl and X is chloro, bromo, iodo, mesyloxy or tosyloxy.