EP0984933A1 - Substituted 2-phenyl pyridines, their manufacture and use as herbicides - Google Patents

Abstract

The invention relates to substituted 2-phenyl pyiridines of formula (I) in which the substituents and index m have the following meanings: m is 0 or 1; R<1> is halogen, C1-C4 halogen alkase, C1-C4 halogen alkoxy, C1-C4-alkylthio, C1-C4-alkyl sulfinyl, C1-C4-alkyl sulfonyl, C1-C4-halogen-alkylthio or cyano; R<2> is fluorine or trifluoromethyl; R<3> is hydrogen or halogen; R<4> is halogen or cyano; R<5> is Co2R<6>, OR<7>, SR<7>, C(R<8>)=N-O-R<7> or C(R<8>)=C(R<8>)-CO-O-R<6>, where R<6> is hydrogen, an unsubstituted or halogen-substituted C1-C8-alkyl-, C3-C6-alkenyl- or C3-C6-alkynyl radical; C1-C4-alkoxy-C1-C4-alkyl, C1-C6-alkoxycarbonyl-C1-C4-alkyl, C3-C4-alkyl, C3-C4-alkenyl oxycarbonyl-C1-C4-alkyl, C3-C4-alkynyl oxycarbonate-C1-C4-alkyl or C1-C4-alkoxy-(C1-C4-alkoxy) carbonyl-C1-C4-alkyl; R<7> has the meaning assigned to R<6> or is CH2-CO2[C1-C4-alkylene]-CO2R<9> and CH[C1-C4-alkyl]-CO2-[C1-C4-alkylene]-CO2R<9>; R<8> is hydrogen or C1-C4 alkyl and R<9> is hydrogen or C1-C4-alkyl.

Description

description

SUBSTITUTED 2-PHENYLPYRIDINE, THE PRODUCTION AND USE THEREOF AS HERBICIDES

The present invention relates to new substituted 2-phenylpyridines of the formula I.

(0) _m R ⁵ in which the substituents and index m have the following meanings:

m 0 or I;

R ¹ halogen, C-- _. - -Halogenalkyl, C ₁ -C ₄ -haloalkoxy, C ₁ -C ₄ -alkyl-thio, -C-C ₄ -alkylsulfinyl, Cι-C ₄ -alkylsulfonyl, C ₁ -C ₄ -halogenylthio or cyano;

R ^{2 is} fluorine or trifluoromethyl;

R ^{3 is} hydrogen or halogen;

R ⁴ halogen or cyano;

R ⁵ C0 ₂ R ⁶ , OR ⁷ , SR ⁷ , C (R ⁸ ) = N-0-R ⁷ or C (R ⁸ ) = C (R ^ö ) -CO-OR ⁶ , where

R ^{6 is} hydrogen, an unsubstituted or halogen-substituted -CC ₈ alkyl, C ₃ -C ₆ alkenyl or C ₃ -C ₆ alkynyl radical; C ₁ -C ₄ alkoxy -CC ₄ -alkyl, Ci -C ₆ -alkoxycarbonyl -Cι-C -alkyl, C ₃ -C -alkenyloxycarbonyl -Ci -C ₄ -alkyl, C ₃ -C ₄ - Alkynyloxycarbonyl -CC ₄ -alkyl or C ₁ -C ₄ -alkoxy- (C1-C4-alkoxy) carbonyl -CC ₄ -alkyl means;

R ^{7 can have} the meaning of R ⁶ or for CH ₂ -C0 ₂ [-C-C ₄ alkylene] -C0 ₂ R ⁹ and

CH [C ₁ -C ₄ alkyl] -C0 ₂ - [Ci-C ₄ alkylene] -C0 ₂ R ⁹ ;

R ^{ö is} hydrogen, halogen or C ₁ -C ₄ alkyl and

R ^{9 represents} hydrogen or C ₁ -C ₄ alkyl, and the agriculturally useful salts of the compounds I.

The invention also relates to

Process for the preparation of the compounds I and intermediates of the formula II, herbicidal agents and agents for the desiccation and / or defoliation of plants which contain the compounds I as active substances,

Process for controlling undesirable plant growth and for desiccating and / or defoliation of plants with the compounds I.

Substituted 2-phenyl-3-chloropyridines with herbicidal activity are already known from WO 95/02580, WO 95/02590 and WO 97/11059.

However, the herbicidal activity of the known compounds with regard to the harmful plants is not always completely satisfactory. The object of the present invention was therefore to provide new herbicidally active compounds which can be used to control undesirable plants better than before. The task also extends to the provision of new desiccant / defoliant connections.

Accordingly, the substituted 2-phenylpyridines of the formula I defined at the outset with herbicidal activity and new intermediates II for their preparation have been found.

Depending on the substitution pattern, the compounds of the formula I can contain one or more centers of chirality and are then present as mixtures of enantiomers or diastereomers. The invention relates both to the pure enantiomers or diastereomers and to mixtures thereof.

The substituted 2-phenylpyridines I with R ^6, R ⁷ and R ⁹ = hydrogen can be present in the form of their agriculturally useful salts, the type of salt generally not being important. In general, the salts of such bases come into consideration in which the herbicidal action is not adversely affected in comparison with the free compound I.

Particularly suitable salts are those of the alkali metals, preferably sodium and potassium salts, of the alkaline earth metals, preferably calcium and magnesium salts, those of the transition metals, preferably zinc and iron salts, and ammonium salts, in which the ammonium ion can carry, if desired, one to four C 1 -C ₄ -alkyl, hydroxy-C 1 -C ₄ -alkyl substituents and / or a phenyl or benzyl substituent, preferably diisopropylammonium, tetramethylammonium, tetrabutylammonium, trimethylbenzylammonium and tri ethyl- (2-hydroxyethyl) ammonium salts, furthermore phosphonium salts, sulfonium such as preferably tri (Cχ-C ₄ -alkyl) sulfonium salts, and sulfoxonium salts such as preferably tri _{(Cι-C4-alkyl)} sulfoxonium.

The terms alkyl, alkylene, haloalkyl, alkoxy, carboxyalkyl, alkoxyalkyl, alkoxycarbonylalkyl, alkenyl and alkynyl used in the definition of the substituents R ¹ , R ⁶ , R ⁷ , R ⁸ and R ⁹ represent - like the meaning of halogen - collective terms for individual enumerations of the individual group members. All alkyl parts can be straight-chain or branched. The haloalkyl radical preferably carries one to five identical or different halogen atoms.

Specifically, for example:

Halogen: fluorine, chlorine, bromine and iodine, preferably fluorine and chlorine;

C ₁ -C ₄ alkyl: methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl and 1, 1-dimethylethyl;

Ci-Cς-alkyl: -C-C ₄ ~ alkyl as mentioned above, and n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2, 2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1, 1 -Dimethylpropyl, 1, 2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1, 1-dimethylbutyl, 1, 2-dimethylbutyl, 1, 3-dimethylbutyl, 2, 2-dimethylbutyl , 2, 3-dimethylbutyl, 3, 3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1, 1, 2-trimethylpropyl, 1, 2, 2-trimethylpropyl, 1-ethyl-l-methylpropyl and l-ethyl -2-methylpropyl;

Ci-Cβ-alkyl: -C ₆ alkyl as mentioned above, and inter alia n-heptyl, n-octyl;

- C ₃ -C ₄ alkenyl: prop-1-en-1-yl, prop-2-en-1-yl, 1-methyl-ethenyl, n-buten-1-yl, n-buten-2-yl , n-buten-3-yl, 1-methyl-prop-1-en-1-yl, 2-methyl-prop-1-en-1-yl, 1-methyl-prop-2-en-1-yl and 2-methyl-prop-2-en-l-yl;

- C ₃ -C ₆ alkenyl: C -C ₄ alkenyl as mentioned above, n-penten-1-yl, n-penten-2-yl, n-penten-3-yl, n-penten-4-yl , 1-methyl-but-l-en-l-yl, 2-methyl-but-l-en-l-yl, 3-methyl but-1-en-l-yl, l-methyl-but-2-en-l-yl, 2-methyl-but-2-en-l-yl, 3-methyl-but-2-en-l- yl, 1-methyl-but-3-en-l-yl, 2-methyl-but-3-en-l-yl, 3-methyl-but-3-en-l-yl, 1, l-dimethyl prop-2-en-l-yl, 1, 2-dimethyl-prop-1-en-l-yl, 1, 2-dimethyl-prop-2-en-l-yl, 1-ethyl-prop-l- en-2-yl, l-ethyl-prop-2-en-l-yl, n-hex-1-en-l-yl, n-hex-2-en-l-yl, n-hex-3- en-l-yl, n-hex-4-en-l-yl, n-hex-5-en-l-yl, 1-methyl-pent-l-en-l-yl, 2-methyl-pent- 1-en-l-yl, 3-methyl-pent-l-en-l-yl, 4-methyl-pent-1-en-l-yl, l-methyl-pent-2-en-l-yl, 2-methyl-pent-2-en-l-yl, 3-methyl-pent-2-en-l-yl, 4-methyl-pent-2-en-l-yl, l-methyl-pent-3- en-l-yl, 2-methyl-pent-3-en-l-yl, 3-methyl-pent-3-en-l-yl, 4-methyl-pent-3-en-l-yl, l- Methyl-pent-4-en-l-yl, 2-methyl-pent-4-en-l-yl, 3-methyl-pent-4-en-l-yl, 4-methyl-pent-4-en- l-yl, 1, l-dimethyl-but-2-en-l-yl, 1, 1-dimethyl-but-3-en-l-yl, 1, 2-dimethyl-but-l-en-l- yl, 1, 2-dimethyl-but-2-en-l-yl, 1, 2-dimethyl-but-3-en-l-yl, 1, 3-dimethyl-but-1-en-l-yl, 1,3-dimethyl-but-2-en-1 -yl, 1,3-dimethyl-but-3-en-l-yl, 2,2-dimethyl-but-3-en-l-yl, 2,3-dimethyl-but-1-en-l-yl , 2, 3-Dimethyl-but-2-en-l-yl, 2, 3-dimethyl-but-3-en-l-yl, 3, 3-dimethyl-but-l-en-l-yl, 3 , 3-Dimethyl-but-2-en-l-yl, 1-ethyl-but-l-en-l-yl, l-ethyl-but-2-en-l-yl, l-ethyl-but-3 -en-1-yl, 2-ethyl-but-1-en-1-yl, 2-ethyl-but-2-en-1-yl, 2-ethyl-but-3-en-1-yl, 1 , 1, 2-Trimethyl-prop-2-en-l-yl, l-ethyl-l-methyl-prop-2-en-l-yl, l-ethyl-2-methyl-prop-l-en-l -yl and l-ethyl-2-methyl-prop-2-en-l-yl, preferably ethenyl and prop-2-en-l-yl;

C ₃ -C ₄ alkynyl: prop-1-in-l-yl, prop-2-in-3-yl, n-but-1-in-l-yl, n-but-l-in-4- yl, n-but-2-in-l-yl;

C ₃ -C ₆ alkynyl: C ₃ - C ₄ alkynyl as mentioned above, n-pent-1-in-yl, n-pent-1-in-3-yl, n-pent-1-yn -4-yl, n-pent-1-in-5-yl, n-pent-2-in-1-yl, n-pent-2-in-4-yl, n-pent-2 -in-5 -yl, 3-methyl-but-1-in-1-yl, 3-methyl-but-1-in-3-yl, 3-methyl-but-1-in-4-yl, n-hex-1 -in-l-yl, n-hex-1-in-3-yl, n-hex-1-in-4-yl, n-hex-1-in-5-yl, n-hex-1-in -6-yl, n-hex-2-in-1-yl, n-hex-2-in-4 -yl, n-hex-2-in-5-yl, n-hex-2-in-6 -yl, n-Hex-3-in-l-yl, n-Hex-3-in-2-yl, 3-methyl-pent-l-in-l-yl, 3-methyl-pent-l-in -3-yl, 3-methyl-pent-1-in-4-yl, 3-methyl-pent-1-in-5-yl, 4-methyl-pent-1-in-1-yl, 4-methyl - pent-2-in-4-yl and 4-methyl-pent-2-in-5-yl, preferably prop-2-in-1-yl, 1-methyl-prop-2 - in-1 -yl; -C-C ₃ -Fluoroalkyl: Cχ-C ₃ alkyl as mentioned above, where in each case 1-5 hydrogen atoms are replaced by fluorine, for. B., fluoromethyl, difluoromethyl, trifluoromethyl, 1-fluoroethyl, 2-fluoroethyl, 2, 2 -difluoroethyl, 2, 2, 2 -trifluoroethyl, pentafluoroethyl, 3, 3, 3-trifluoropropyl, preferably difluoromethyl, trifluoromethyl, 2nd , 2, 2 -trifluoroethyl, pentafluoroethyl and 3, 3, 3 -trifluoropropyl, particularly preferred is trifluoromethyl;

-C 1 -C ₄ haloalkyl: -C ₄ C ₄ -alkyl as mentioned above, which is partially or completely substituted by fluorine, chlorine and / or bromine, for example chloromethyl, dichloromethyl, trichloromethyl, fluoromethyl, difluoromethyl, trifluoromethyl, chlorofluoromethyl, Dichlorofluoromethyl, chlorodifluoromethyl, 1-fluoroethyl, 2-fluoroethyl, 2, 2-difluoroethyl, 2, 2, 2-trifluoroethyl, 2-chloro-2-fluoroethyl, 2-chloro-2, 2-difluoroethyl, 2, 2-dichloro 2-fluoroethyl, 2, 2, 2-trichloroethyl, pentafluoroethyl and 3-chloropropyl, preferably trifluoromethyl;

-C-C-haloalkoxy: C- _L -C ₄ -alkoxy as mentioned above, which is partially or completely substituted by fluorine, chlorine and / or bromine, for example chloromethoxy, dichloromethoxy, trichloromethoxy, fluoromethoxy, difluoromethoxy, trifluoromethoxy, Chlorofluoromethoxy, dichlorofluoromethoxy, chlorofluoromethoxy, 1-fluoroethoxy, 2-fluoroethoxy, 2,2-difluoroethoxy, 2, 2, 2-trifluoroethoxy, 2-chloro-2-fluoroethoxy, 2-chloro-2, 2-difluoroethoxy, 2, 2-dichloro-2-fluoroethoxy, 2, 2, 2-trichloroethoxy and pentafluoroethoxy, preferably C ₁ -C ₂ haloalkoxy such as trifluoromethoxy;

C _! -C ₄ -Alkylthiθ: methylthio, ethylthio, n-propylthio, 1-methylethylthio, n-butylthio, 1-methyl-propylthio, 2-methylpropylthio and 1, 1-dimethylethylthio, preferably methylthio, ethylthio, methylethylthio;

_{Cι-C4-haloalkylthio:} chloromethylthio, dichloromethylthio, trichloromethylthio, fluoromethylthio, difluoromethylthio, trifluoromethylthio, Chlorfluormethylthio, dichlorofluoromethylthio, chlorodifluoromethylthio, 1-fluoroethylthio, 2-fluoroethylthio, 2,2-Dif luorethylthio, 2, 2, 2-trifluoroethylthio,

2-chloro-2-fluoroethylthio, 2-chloro-2, 2-difluoroethylthio, 2, 2-dichloro-2-fluoroethylthio, 2, 2, 2-trichloroethylthio and pentafluoroethylthio, preferably C ₁ -C ₂ haloalkylthio such as Trif luormethylthio; Cι ~ C ₄ alkylsulfonyl: methylsulfonyl, ethylsulfonyl, n-propylsulfonyl, 1-methylethylsulfonyl, n-butylsulfonyl, 1-methyl-propylsulfonyl, 2-methylpropylsulfonyl and 1, 1-dimethylethylsulfonyl;

-C-C ₄ alkylsulfinyl: methylsulfinyl, ethylsulfinyl, n-propylsulfinyl, 1-methylethylsulfinyl, n-butylsulfinyl, 1-methylpropylsulfinyl, 2-methylpropylsulfinyl and 1, 1-dimethylethylsulfinyl;

Cι-C alkoxy-C ₁ -C ₄ alkyl: by Cι-C ₄ alkoxy such as methoxy, ethoxy, n-propoxy, 1-methylethoxy, n-butoxy, 1-methylpropoxy, 2-methylpropoxy and 1, 1 -Dimethylethoxy substituted C ₁ -C ₄ alkyl, e.g. for CH ₂ OCH ₃ , CH ₂ OC ₂ H ₅ , n-propoxymethyl, (l-methylethoxy) methyl, n-butoxymethyl, (1-methylpropoxy) - methyl, ( 2-methylpropoxy) methyl, (1, 1-dimethylethoxy) methyl, 2- (methoxy) ethyl, 2- (ethoxy) ethyl, 2- (n-propoxy) ethyl, 2- (1-methylethoxy) ethyl, 2- ( n-butoxy) ethyl, 2- (l-methylpropoxy) ethyl, 2- (2-methylpropoxy) ethyl, 2- (1, 1-dimethylethoxy) ethyl, 2- (methoxy) propyl, 2- (ethoxy ) propyl, 2- (n-propoxy) propyl, 2- (1-methylethoxy) propyl, 2- (n-butoxy) propyl, 2- (1-methylpropoxy) propyl, 2- (2-methylpropoxy) propyl, 2- (1, 1-dimethylethoxy) propyl, 3- (methoxy) propyl, 3- (ethoxy) propyl, 3- (n-propoxy) propyl, 3- (l-methylethoxy) propyl, 3- (n-butoxy) propyl, 3- (1-methylpropoxy) propyl, 3- (2-methylpropoxy) propyl, 3- (1, 1-dimethylethoxy) propyl, 2- (Me thoxy) butyl, 2- (ethoxy) butyl, 2- (n-propoxy) butyl, 2- (l-methylethoxy) butyl, 2- (n-butoxy) butyl, 2- (l-methylprooxy) butyl, 2 - (2-Methylpropoxy) butyl, 2- (1, 1-dimethylethoxy) butyl, 3- (methoxy) butyl, 3- (ethoxy) butyl, 3- (n-propoxy) butyl, 3- (1-methylethoxy ) butyl, 3- (n-butoxy) butyl, 3- (1-methylpropoxy) butyl, 3- (2-methylpropoxy) butyl, 3- (1, 1-dimethylethoxy) butyl, 4- (methoxy) butyl, 4- (Ethoxy) butyl, 4- (n-propoxy) butyl, 4- (1-methylethoxy) butyl, 4- (n-butoxy) butyl, 4- (1-methylpropoxy) butyl, 4- (2-methylpropoxy ) butyl or 4- (1, 1-dimethylethoxy) butyl, preferably n-propoxymethyl, (1-methylethoxy) methyl, 2 - (n-propoxy) ethyl and 2- (l-methylethoxy) ethyl and particularly preferably CHOCH, CH ₂ OC ₂ H ₅ , 2-methoxyethyl or 2-ethoxyethyl;

(-CC ₆ alkoxy) carbonyl -CC ₂ -alkyl for: by (-C ₆ -alkoxy) carbonyl such as COOCH ₃ , COOC ₂ H ₅ , n-propoxycarbonyl, COOCH (CH ₃ ) ₂ , n- Butoxycarbonyl, 1-methylpropoxycarbonyl, 2-methylpropoxycarbonyl COOC (CH ₃ ) ₃ n-pentoxycarbonyl, 1-methyl-butoxycarbonyl and n-hexoxycarbonyl substituted C 1 -C ₄ alkyl, e.g. for CH ₂ -COOCH ₃ , CH ₂ -COOC ₂ H ₅ , n-propoxycarbonylmethyl, CH ₂ -COOCH (CH ₃ ) ₂ , n-butoxycarbonylmethyl, (1-methylpropoxycarbonyl) ethyl, (2-methylpropoxycarbonyl) methyl, CH ₂ -COOC (CH ₃ ) ₃ , n-pentoxycarbonylmethyl, (1-methylbutoxycarbonyl) methyl, n-hexoxycarbonylmethyl, l- (methoxycarbonyl) ethyl, 1- (ethoxycarbonyl) ethyl, 1- (n-propoxycarbonyl) ethyl, 1 - (1-methylethoxycarbonyl) ethyl, 1- (n-butoxycarbonyl) ethyl, 1 - (n-pentoxycarbonyl) ethyl, 1- (1 - Methyl-butoxycarbonylethyl, 1 - (n-hexoxycarbonyl) ethyl, 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (n-propoxycarbonyl) ethyl, 2- (1-methylethoxycarbonyl) ethyl, 2- (n-butoxycarbonyl) ethyl, 2- (1-methylpropoxycarbonyl) ethyl, 2- (2-methylpropoxycarbonyl) ethyl, 2- (1, 1-dimethylethoxycarbonyl) ethyl;

(C ₁ -C ₆ -alkoxy) carbonyl -CC ₄ -alkyl for: (-C ₆ -alkoxy) carbonyl-C ₄ -C ₆ -alkyl as mentioned above, and 2- (methoxycarbonyl) propyl, 2- (ethoxycarbonyl) propyl, 2- (n-propoxycarbonyl-propyl, 2- (1-methylethoxycarbonyl) propyl, 2- (n-butoxycarbonyl-propyl, 2- (1-methylpropoxycarbonyl) propyl, 2- (2-methyl- propoxycarbonyl) propyl, 2- (1, 1-dimethylethoxycarbonyl) propyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl, 3- (n-propoxycarbonyl) ropyl, 3- (1-methylethoxycarbonyl) propyl, 3- (n-butoxycarbonyl) propyl, 3- (1-methylpropoxycarbonyl) ropyl, 3- (2-methylpropoxycarbonyl) propyl, 3- (1, 1-dimethylethoxycarbonyl) propyl, 2- (methoxycarbonyl) butyl, 2- (ethoxycarbonyl ) butyl, 2- (n-propoxycarbonyl) butyl, 2- (1-methylethoxycarbonyl) butyl, 2- (n-butoxycarbonyl) butyl, 2- (1-methylpropoxycarbonyl) butyl, 2- (2-methylpropoxycarbonyl) butyl, 2- (1, 1-dimethylethoxycarbonyl) butyl, 3- (methoxycarbonyl) butyl, 3- (ethoxycarbonyl) butyl, 3- (n-propoxyc arbonyl) butyl, 3- (1-methylethoxycarbonyl) butyl, 3- (n-butoxycarbonyl) butyl, 3- (1-methylpropoxycarbonyl) butyl, 3- (2-methylpropoxycarbonyl) butyl, 3- (1, 1-dimethylethoxycarbonyl) ) butyl, 4- (methoxycarbonyl) butyl, 4- (ethoxycarbonyl) butyl, 4- (n-propoxycarbonyl) butyl, 4- (l-methylethoxycarbonyl) butyl, 4- (n-butoxycarbonyl) butyl, 4- (l -Methyl-propoxycarbonyl) butyl, 4- (2-methylpropoxycarbonyl) butyl or 4- (1, 1-dimethylethoxycarbonyl) butyl, preferably CH ₂ -COOCH ₃ , CH ₂ -COOC ₂ H ₅ , 1- (methoxycarbonyl) ethyl or 1 - (Ethoxycarbonyl) ethyl;

-C -alkoxy- (-C ~ C ₃ alkoxy) carbonyl -CC -C ₂ alkyl for: by

OCH ₃ , OC- ₂ H ₅ , OCH ₂ -C ₂ H ₅ or OCH (CH ₃ ) ₂ in the C _λ -C ₃ alkoxy part substituted (-C-C ₃ -alkoxy) carbonyl-Cι-C ₆ -alkyl such as CH ₂ COOCH ₃ , CH ₂ COOC ₂ H ₅ , CH ₂ COOCH ₂ -C ₂ H ₅ , CH ₂ COOCH (CH ₃ ) ₂ , CH (CH ₃ ) COOCH ₃ , CH (CH ₃ ) COOC ₂ H ₅ , CH ₂ CH ₂ COOCH ₃ , CH ₂ CHCOOC ₂ H ₅ , CH ₂ CH ₂ COOCH ₂ -C ₂ H ₅ , CH ₂ CH ₂ COOCH (CH ₃ ) ₂ , 2- (COOCH ₃ ) propyl, 2- (COOC ₂ H ₅ ) propyl, 2- (COOCH ₂ -C ₂ H ₅ ) propyl, 2- [COOCH (CH ₃ ) ₂ ] propyl, 3- (COOCH ₃ ) propyl, 3- (COOC ₂ H ₅ ) propyl, 3- (COOCH ₂ -C ₂ H ₅ ) propyl, 3- [COOCH (CH ₃ ) ₂ ] propyl, preferably CH ₂ COOCH ₃ or CH ₂ COOC ₂ H ₅ , e.g. for CH ₂ COOCH ₂ OCH ₃ , CH ₂ COOCH ₂ OC ₂ H ₅ , CH ₂ COOCH ₂ OCH ( CH ₃ ) ₂ or CH ₂ COOCH ₂ OC (CH ₃ ) ₃ ;

- -C -alkoxy- (C ₁ -C ₄ -alkoxy) carbonyl -C -C ₄ -alkyl for:

-C-C ₃ -alkoxy- (Cχ-C- ₃ -alkoxy) carbonyl-C _! -C ₂ alkyl as mentioned above, moreover one or both alkoxy parts can be n-butoxy, sec-butoxy, iso-butoxy or tert-butoxy and 2- (COOCH ₃ ) butyl, 2- (COOC ₂ H ₅ ) butyl, 2- (COOCH ₂ -C ₂ H ₅ ) butyl, 2- [COOCH (CH ₃ ) ₂ ] butyl, 3- (COOCH ₃ ) butyl, 3- (COOC ₂ H ₅ ) butyl,

3- (COOCH ₂ -C ₂ H ₅ ) butyl, 3- [COOCH (CH ₃ ) ₂ ] butyl, 4- (COOCH ₃ ) butyl,

4- (COOC- ₂ H ₅ ) butyl, 4- (COOCH ₂ -C ₂ H ₅ ) butyl, 4- [COOCH (CH ₃ ) ₂ ] butyl;

C -C alkylene is e.g. for methylene, 1,1-ethylene, 1,2-ethylene, 1, 1-propylene, 1, 2-propylene, 1, 3-propylene, 2, 2-propylene,

1,1-butylene, 1,2-butylene, 1,3-butylene, 1,4-butylene, 2,2-butylene, 2,3-butylene, 2-methyl-1, 1-propylene, 2-methyl- 1, 2-propylene or 2-methyl-1, 3-propylene, preferably for methylene, 1,1-ethylene or 2, 2-propylene.

With regard to the use of the substituted 2-phenylpyridines I according to the invention as herbicides and / or as desiccant / defoliant compounds, the substituents and index m preferably have the following meanings, individually or in combination:

m 0,

R ¹ -C ₃ -C ₃ fluoroalkyl, chlorine, methylsulfonyl or cyano;

R ^{2 is} fluorine or trifluoromethyl;

R ³ fluorine or chlorine;

R ⁴ chlorine;

R ⁵ C0 ₂ R ⁶ , OR ⁷ or SR ⁷ , where

R ^{6 is} hydrogen, Ci-Cs-alkyl, C ₃ -C -alkenyl, 3-chloroprop-2-ene, C ₃ -C ₄ -alkynyl, -C-C ₃ -alkoxy-Cι-C ₂ -alkyl, C _x -C ₆ -Alkoxycar- carbonyl-Cι-C ₂ alkyl, Ci-propargyloxycarbonyl -C ₂ - alkyl, C ₁ -C ₃ - alkoxy C ₁ -C ₃ - alkoxy carbonyl -C -C - alkyl group;

R ^{7 can have} the meaning of R ⁶ or for CH ₂ -C0 ₂ [-C-C ₂ -alkylene] C0 ₂ R ⁹ and CH [C _X -C ₂ -

Alkyl] -C0 ₂ [-C-C ₂ -alkylene] C0 ₂ R ⁹ ; R ^{8 is} hydrogen, halogen or C1-C4-alkyl and

R ^{9 represents} hydrogen or C ₁ -C ₄ alkyl,

and the agriculturally useful salts of the compounds

I.

The substituted 2-phenylpyridines la (= I with m = 0, R ² = fluorine, R ⁴ = chlorine) are particularly preferred, in particular the compounds listed in Table A below:

Also preferred are the substituted 2-phenylpyridines Ib (I I with m = 0, R ² = trifluoromethyl, R ⁴ = chlorine), in particular the compounds listed in Table B below:

The substituted 2-phenylpyridines can be obtained in various ways, for example by the processes described in WO 95/02580 and WO 97/11059. The corresponding 2-phenylpyridine-N-oxides of the formula I (m = 1) can be prepared in analogy to the process described in Wo 97/11059. A more recent form of coupling pyridine and phenyl components was described in DE No. 196 36995.9, according to which the pyridine sulfoxides Ilb and pyridine sulfones IIc are reacted with Grignard or zinc compounds III and IV to give the end products I according to the invention.

In formula III and IV, R ³ to R ^{5 have} the meaning given in claim 1 and X each represents a halogen atom. Intermediates III and IV and their preparation are described in DE Application No. 196 36995.9. n = 0 Ha n = 1 Ilb n = 2 IIC

The thiopyridines II can be prepared in analogy to the procedure described in DE No. 196 36997.5. In DE note no. 19722661.2 shows a particularly favorable access to thiopyridines II starting from 2 -halopyridines V and thio compounds of the formula VI in the presence of a copper catalyst.

In formula II, R ¹ and R ^{2 have} the meaning given in claim 1. The pyridine thioethers of the formula Ha (n = 0) are starting materials for the preparation of the pyridine sulfoxides Ilb (n = 1) and pyridine sulfones IIc (n = 2); the latter two are used in the coupling reaction with III and IV. Z represents an unsubstituted or substituted by halogen, C 1 -C ₄ -alkoxy-, C 1 -C ₄ -alkoxy carbonyl, di- (C 1 -C ₄ -alkylamino) carbonyl, cyano or nitro-substituted C 1 -C ₀ -alkyl- , C -C ₀ - alkenyl or C ₂ -Cι ₀ alkynyl radical, a C ₃ -C ₈ cycloalkyl radical or one which is unsubstituted in the phenyl part or by halogen, Cι-C ₃ alkyl, Cχ-C ₃ alkoxy, trifluoromethyl, Cyano or nitro substituted -CC ₄ alkylenephenyl, phenyl or naphthyl radical.

The terms alkyl, alkenyl, alkynyl, alkylene, alkoxy, alkoxycarbonyl, dialkylaminocarbonyl, cycloalkyl used in the definition of the substituent Z are collective terms for individual lists of the individual group members. All alkyl parts can be straight-chain or branched. The haloalkyl radical preferably carries one to five identical or different halogen atoms.

Specifically mean, for example

C -] _- -Cιo-alkyl: Ci-Cβ-alkyl as in the definition of substituents of R ⁶ and n-nonyl and n-decyl;

optionally halogen, C ₃ -C ₃ alkyl, C ₁ -C ₃ alkoxy, trifluoromethyl, cyano or nitro substituted 1-phenyl, 2-, 3-, 4-chlorophenyl, 2-, 3-, 4-tolyl, 2-chloro-4-methylphenyl, 2, 4-dichlorophenyl, 2, 4, 6-trichlorophenyl, 2, 6-dichloro-4-methylphenyl, 2-, 3-, 4-meth- oxyphenyl, 2-chloro-4-methoxyphenyl, 3-chloro-4-methoxyphenyl, 2- 3-, 4-trifluoromethylphenyl, 2-, 3-, 4-cyanophenyl, 2-, 3-, 4-nitrophenyl, 2 -Methyl-4-nitrophenyl, 2-chloro-4-trifluoromethylphenyl, 2-chloro-4-nitrophenyl and unsubstituted phenyl. i Particularly preferred are those compounds II in which

n 1 or 2;

Rl trifluoromethyl, chlorine, methylsulfonyl or cyano;

R ² fluorine or trifluoromethyl and

Z is an unsubstituted or substituted by chlorine or methoxy Ci-Ca alkyl radical, a benzyl or phenyl radical which is unsubstituted in the phenyl part or is substituted by halogen, methyl, C ₁ -C ₃ alkoxy, trifluoromethyl, cyano or nitro.

In particular, the following pyridine thioethers Ha from Tables 1-4, the pyridine sulfoxides IIb from Tables 5-8 and the pyridine sulfones IIc from Tables 9-12 are mentioned.

The pyridine thioethers 11.001-11.116 of the formula Shark mentioned in Table 1 are preferred

0

5 Table 1

Table 2

Furthermore, the pyridine thioethers Ila2.001 - IIa2.116 of the formula IIa2 are preferred, which differ from the compounds IIal.001 - Ilal.116 in that a trifluoromethyl group is in the 5-position on the pyridine ring instead of chlorine.

Table 3

Furthermore, the pyridine thioethers IIa3.001 - IIa3.116 of the formula IIa3 are preferred, which differ from the compounds

IIal.001 - IIal.116 differ in that there is a methylsulfonyl group in the 5-position on the pyridine ring.

Table 4

Furthermore, the pyridine thioethers Ila4.001 - IIa4.116 of the formula IIa4 are preferred, which differ from the compounds Ilal.OOl - IIal.116 in that a cyano group is in the 5-position on the pyridine ring instead of chlorine.

Table 5

Furthermore, the thiopyridines IIbI.001-IIbl.116 of the formula IIbl are preferred, which differ from the compounds Ilal.OOl-IIal.116 in that the corresponding sulfoxides are present.

Table 6

Furthermore, the thiopyridines IIb2.001 - IIb2.116 of the formula IIb2 are preferred, which differ from the compounds IIa2.001 - IIa2.116 in that the corresponding sulfoxides are present.

Table 7

Furthermore, the thiopyridines IIb3.001 - IIb3.116 of the formula IIb3 are preferred, which differ from the compounds IIa3.001 - IIa3.116 in that the corresponding sulfoxides are present.

CH ₃ Table 8

Furthermore, the thiopyridines IIb4.001 - IIb4.116 of the formula IIb4 are preferred, which differ from the compounds IIa4.001 - IIa4.116 in that the corresponding sulfoxides are present.

Table 9

Furthermore, the thiopyridines IIcI.001 - IIcl.116 of the formula IIcl are preferred, which differ from the compounds Ilal.OOl - IIal.116 in that the corresponding sulfones are present.

Table 10

Furthermore, the thiopyridines IIc2.001 - IIc2.116 of the formula IIc2 are preferred, which differ from the compounds IIa2.001 - IIa2.116 in that the corresponding sulfones are present.

Table 11

Furthermore, the thiopyridines IIc3.001 - IIc3.116 of the formula Ilc3 are preferred, which differ from the compounds Ila3.001 - IIa3.116 in that the corresponding sulfones are present.

Table 12

Furthermore, the thiopyridines IIc4.001 - IIc4.116 of the formula IIc4 are preferred, which differ from the compounds IIa4.001 - IIa4.116 in that the corresponding sulfones are present.

In the case of the preparation of the compounds Ila-c using 2, 3-difluoro-5-trifluoromethylpyridine and thiophenol as the nucleophile and when using hydrogen peroxide as the oxidizing agent, the reaction can be described by the following scheme:

Instead of hydrogen peroxide as the oxidizing agent, peracetic acid, sodium hypochlorite or chlorine and bromine can also be used analogously according to the above scheme.

Preferred embodiments of the method are mentioned below.

The reaction of the 2 -halopyridines V with a thiol VI is advantageously carried out in the presence of a solvent at temperatures in the range from 80-250 ° C., preferably 120-200 ° C., particularly preferably 140-180 ° C.

Depending on the temperature range, the solvents used for these reactions are hydrocarbons such as toluene, xylene, chlorinated hydrocarbons such as 1,2-dichloroethane, 1, 1, 2, 2-tetrachloroethane, chlorobenzene, 1,2- 1,3- or 1,4-dichlorobenzene, ether such as 1,4 dioxane, anisole, glycol ethers such as dimethyl glycol ether, diethyl glycol ether, diethylene glycol dimethyl ether, esters such as ethyl acetate, propyl acetate, methyl isobutyrate, isobutyl acetate, carboxylic acid amides such as DMF, N-methylpyrrolidone, nitro hydrocarbons 5 such as nitrobenzene, tetrabutyl tetrabutyl ether urea, dimethylethylene urea, dimethyl propylene urea, sulfoxides such as dimethyl sulfoxide, sulfones such as dimethyl sulfone, diethyl sulfone, tetramethylene sulfone, nitriles such as acetonitrile, propionitrile, butyronitrile or isobutyronitrile; Water or 0 mixtures of individual solvents.

Execution in the melt without the use of a solvent is particularly preferred.

5 The molar ratios in which the starting compounds are reacted with one another are generally 0.9-1.4, preferably 0.95-1.1, particularly preferably 0.98-1.04, for the ratio of thiol to 2 -Halogen pyridine V. The concentration of the starting materials in the solvent is 0.1-5 mol / 1, preferably 0.2-0.2 mol / 1.

The reaction is accelerated by the presence of a copper catalyst. Suitable catalysts are copper oxide, salts such as copper (II) chloride, copper sulfate, copper nitrate, copper acetate,

25 copper carbonate. It is particularly preferred to use metallic copper in fine distribution, e.g. B. copper powder or copper bronze. The molar amount of catalyst based on the 2-halopyridine V is 0.001-10, preferably 0.001-1, particularly preferably 0.001-0.1 mol%.

30

The reaction can also be carried out in the presence of an organic base, such as. B. triethylamine, tri-n-propylamine, N-ethyldiisopropylamine, pyridine, α-, ß-, γ-picoline, 2, 4 -, 2, 6 -lutidine, n-methylpyrrolidine, triethylenediamine, dimethylaniline, N, N-dimethylcyclohexylamine ,

35 Perform quinoline or acridine.

The reaction is preferably carried out under acidic conditions, in which the hydrogen halide split off in the reaction is discharged from the reaction mixture by means of an inert gas, for example nitrogen, or is allowed to escape into a washing device under autogenous pressure.

The 2 -halopyridine V is advantageously added for 10 to 60 min. to a mixture of the thiol VI and the catalyst at 45 20-80 ° C and then stirred to complete the reaction 0.5 to 12 hours, preferably 1 to 8 hours at 140-180 ° C after.

However, the thiol VI can also be added to a mixture of 2-halopyridine V and catalyst and the reaction can then be completed as above.

In the case of low-boiling 2 -halopyridines V or thiols VI, the reaction can also be carried out in an autoclave.

If only one of the two starting components has a low boiling point, the higher-boiling component can be introduced together with the catalyst and the low-boiling component - depending on its consumption - directly at the reaction temperature of preferably 120-200 ° C., particularly preferably 140-180 ° C or gas.

The reaction can be carried out under pressure or under pressure, continuously or batchwise.

The oxidation of the pyridine thioethers of the formula Ha to the pyridine sulfoxides IIb and pyridine sulfones IIc can advantageously be carried out using hydrogen peroxide, the pyridine sulfoxides IIb being obtained with approximately equivalent amounts of oxidant and the pyridine sulfones IIc being obtained with approximately double molar amounts.

Water, acetonitrile, carboxylic acids such as acetic acid, trifluoroacetic acid, propionic acid, alcohols such as methanol, ethanol, isopropanol, tert. -Butanol, chlorinated hydrocarbons such as methyl ethyl ketone can be used. Water, methanol, acetic acid and trifluoroacetic acid are particularly preferred.

In a particularly preferred variant, the reaction can also be catalyzed by adding stronger acids such as trifluoroacetic acid or perchloric acid. However, metal compounds are also suitable as catalysts, e.g. B. transition metal oxides such as vanadium pentoxide, sodium tungstate, potassium dichromate, iron oxide tungstate, sodium tungstate, molybdic acid, osmic acid, titanium trichloride, selenium dioxide, phenylene selenic acid, oxovanadinyl -2, 4-pentanedioate.

The catalysts are generally used in an amount of 0.5 to 10%, but because of the easy filterability and recovery of the inorganic catalysts, stoichiometric amounts can also be used. Another preferred oxidizing agent is peracetic acid or hydrogen peroxide / acetic anhydride, optionally also the peracetic acid present in equilibrium in a hydrogen peroxide / acetic acid mixture.

A preferred oxidizing agent is also pertrifluoroacetic acid or the mixture of hydrogen peroxide / trifluoroacetic acid or the mixture of hydrogen peroxide / trifluoroacetic anhydride.

Oxidation with water peroxide in glacial acetic acid is generally very selective, but is often slow. The reaction time can generally be shortened by adding trifluoroacetic acid. Oxidation with hydrogen superoxide in pure trifluoroacetic acid often leads, as also described in Chimia 29 (1975) 466, to the formation of the corresponding N-oxides. A rapid and selective oxidation of the pyridine thioethers Ha to the corresponding sulfoxides Ilb and sulfones IIc is possible with solutions of hydrogen superoxide in mixtures of acetic acid and trifluoroacetic acid in a volume ratio of 10: 1 to 1: 1, in particular 6: 1 to 4: 1. These mixtures are therefore particularly preferred as solvent.

Petroleum ether, the abovementioned solvents and the catalysts listed above can also be used as solvents.

In addition to peracetic acid and pertrifluoroacetic acid, perbenzoic acid, monoperphthalic acid or 3-chloroperbenzoic acid can also advantageously be used in chlorinated hydrocarbons such as methylene chloride or 1,2-dichloroethane.

Chlorine and bromine are also very suitable for the oxidation of the thiols to sulfoxides or sulfones. Favorable solvents are water, acentontril, dioxane, two-phase systems such as aqueous potassium hydrogen carbonate solution / dichloromethane and, in the case of pyridine alkyl thioether, also acetic acid.

As a source of active halogen can also tert. -Butyl hypochlorite, hypochlorous and bromonic acid, the salts thereof, and also H-halogen compounds such as N-bromine and N-chlorosuccinimide or sulfuryl chloride.

Favorable for the oxidation are also dinitrogen tetroxide z. B. in the process engineering simple variant with air / nitrogen dioxide or trioxide and, for example, osmium (VII) oxide as a catalyst. In addition, the oxidation can also be carried out directly with Acid are carried out, with acetic anhydride, acetic acid as additional solvents and copper (I) and (II) bromide and chloride as catalysts.

Photosensitized oxygen transfer is also suitable for the oxidation, chlorophyll, protoporphyrin, Rose Bengal or methylene blue being recommended as photosensitizers. As inert solvents are hydrocarbons such as pentane, hexane, heptane, cyclohexane, chlorinated hydrocarbons such as methylene chloride, 1, 2-dichloroethane, 1, 1, 2, 2, tetrachloroethane, alcohols such as methanol, ethanol, n-propanol or isopropanol, ketones such as Acetone, methyl ethyl ketone, polar aprotic solvents such as acetonitrile, propionitrile or aromatic hydrocarbons such as benzene, toluene, chlorobenzene or xylene are suitable. Instead of oxygen, it is also possible to use ozone in the abovementioned solvents, in addition to ether, 1,4-dioxane or THF.

In addition to photosensitization, catalysts are also recommended for oxygen oxidation. B. oxides and sulfides of nickel, copper, aluminum, tungsten, chromium, vanadium, ruthenium, titanium, manganese, molybdenum, magnesium and iron.

Depending on the stoichiometry of the oxidizing agents used, either pyridine sulfoxides Ilb or their pyridine sulfones IIc are obtained. The molar ratios in which the starting compounds are reacted with one another are generally 0.9-1.8, preferably 1.05-1.3 for the ratio of pyridine thioether Ha to oxidizing agent in the case of oxidation to pyridine sulfoxide IIb and generally 1 , 9 - 3.5, preferably 2.05 - 2.9 in the case of oxidation to pyridine sulfone IIc.

the concentration of the starting materials in the solvent is generally 0.1-5 mol / 1, preferably 0.2-2 mol / 1.

Advantageously, the pyridine thioether or the pyridine sulfoxide, if appropriate with one of the abovementioned catalysts, is initially introduced into one of the abovementioned solvents, and the oxidizing agent is then added over the course of 0.25-20 hours while stirring. The addition and reaction temperature depends on the optimal efficiency of the respective oxidizing agent and the avoidance of side reactions. If photosensitized oxygen is used, the process is generally carried out at from -20 to 80 ° C., but is generally metal-catalyzed at from 50 to 140 ° C. and, when using ozone, generally at from -78 to 60 ° C. Due to the limited solubility of the oxygen derivatives, they have to be continuously added to the over a longer period (up to 20 hours) Reaction mixture are gasified until the oxidation is completed on the sulfoxide or sulfone stage. If air / nitrogen dioxide or trioxide is used, work is preferably carried out at 15-150 ° C. for 1-15 hours. Liquid or 5 easily soluble oxidizing agents such as hydrogen superoxide, the peracetic acid formed together with acetic anhydride or in equilibrium with acetic acid or trifluoroacetic acid or pertrifluoroacetic acid, hypochlorous or bromonic acid, tert. -Butylhy- pochlorite, chlorine or bromine, N-chlorine, or N-bromosuccinimide or

Depending on the exothermic nature of the reaction, 10 nitric acid can be added to the reaction mixture of the pyridine thioether or sulfoxide in a shorter period of time from 0.25 to 6 hours in order to bring the reaction to a conclusion after a further 1 to 60 hours. A staggered addition of the liquid is also preferred

15 or dissolved oxidizing agent. In the case of hydrogen superoxide and peracetic acid or pertrifluoroacetic acid, it is generally carried out at 0 - 90 ° C, with tert. -Butyl hypochlorite in general at -78 to 30 C, with N-halogen compounds in general at 0 - 30 ° C and with nitric acid in general at 20 to

20 140 ° C. In the case of chlorine or bromine, a reaction temperature of 0 - 40 ° C is recommended.

The oxidations can be operated without pressure or under pressure, continuously or batchwise.

25

The multistage reaction can advantageously also be carried out as a one-pot process, the thioethers Ha obtained in the first synthesis step in the reaction of the 2 -halopyridines V with the thiols VI being added directly without isolation and purification

30 the sulfoxides Ilb or the sulfones IIc. Accordingly, the reaction product Ha is optionally cooled to 90 to 120 ° C, optionally a solvent, for. B. trifluoroacetic acid, preferably acetic acid and / or water and now adds the oxidizing agent according to its consumption

35 added. Hydrogen superoxide, especially sodium hypochlorite, are preferred as oxidizing agents.

For working up, the intermediates Ila-c are taken up in a water-immiscible solvent, acidic impurities or oxidizing agents are extracted with dilute alkali or water, dried and the solvent is removed under reduced pressure.

The substituted 2-phenylpyridines I can normally be prepared after 45 by one of the synthesis methods mentioned above. For economic or procedural reasons, however, it may be more convenient to use some compounds I from similar ones 2-Phenylpyridinen, but differ in the meaning of a residue.

The reaction mixtures are generally worked up by methods known per se, for example by diluting the reaction solution with water and then isolating the product by means of filtration, crystallization or solvent extraction, or by removing the solvent, distributing the residue in a mixture of water and a suitable organic solvent and working up the organic phase towards the product.

The substituted 2-phenylpyridines of the formula I can contain one or more centers of chirality and are then usually obtained as mixtures of enantiomers or diastereomers. If desired, the mixtures can be separated into the largely pure isomers by the customary methods such as crystallization or chromatography, including on an optically active adsorbate. Pure optically active isomers can also be produced, for example, from corresponding optically active starting materials.

Those substituted 2-phenylpyridines I with R ⁶ <R ⁷ and R ⁹ = hydrogen can be converted into their salts, preferably into their alkali metal salts, in a manner known per se.

Salts of I, the metal ion of which is not an alkali metal ion, can be prepared in a conventional manner by salting the corresponding alkali metal salt, as can ammonium, phosphonium, sulfonium and sulfoxonium salts using ammonia, phosphonium, sulfonium or sulfoxonium hydroxides.

The compounds I and their agriculturally useful salts are suitable - both as isomer mixtures and in the form of the pure isomers - as herbicides. The herbicidal compositions containing I control vegetation very well on non-cultivated areas, particularly when high amounts are applied. In crops such as wheat, rice, corn, soybeans and cotton, they act against weeds and grass weeds without significantly damaging the crop plants. This effect occurs especially at low application rates.

Depending on the particular application method, the compounds I or compositions containing them can also be used in a further number of crop plants for eliminating undesired plants. The following crops are considered, for example: Allium cepa, pineapple co osus, Arachis hypogaea, Asparagus officinalis, Beta vulgaris spec. altissima, Beta vulgaris spec. rapa, Brassica napus var. napus, Brassica napus var. napobrassica, Brassica rapa var. silvestris, Camellia sinensis, Carthamus tinctorius, Carya illinoinensis, Citrus limon, Citrus sinensis, Coffea arabica (Coffea canephora, Coffea libericaus), Cucumodison , Daucus carota, Elaeis guineensis, Fragaria vesca, Glycine max, Gossypium hirsutum, (Gossypium arboreum, Gossypium herbaceum, Gossypium vitifolium), Helianthus annuus, Hevea brasiliensis, Hordeum vulgare, Humulus lupulus, Ipomoealumisisumisum , Lycopersicon lycopersicum, Malus spec, Manihot esculenta, Medicago sativa, Musa spec, Nicotiana tabacum (N. rustica), Olea europaea, Oryza sativa, Phaseolus lunatus, Phaseolus vulgaris, Picea abies, Pinus spec, Pisum sativum, Prunus avium, Prunus persica, Pyrus com unis, Ribes sylestre, Ricinus communis, Saccharum officinarum, Seeale cereale, Solanum tuberosum, Sorghum bicolor (see vulgar), Theobroma cacao, Trifolium prate nse, Triticum aestivum, Triticum durum, Vicia faba, Vitis vinifera, Zea mays.

In addition, the compounds I can also be used in crops which are tolerant to the action of herbicides by breeding, including genetic engineering methods.

Furthermore, the substituted 2-phenylpyridines I are also suitable for the desiccation and / or defoliation of plants.

As desiccants, they are particularly suitable for drying out the aerial parts of crops such as potatoes, rapeseed, sunflower and soybeans. This enables a fully mechanical harvesting of these important crops.

Also of economic interest is the ease of harvesting, which is made possible by the temporally concentrated decrease or decrease in the adhesive strength on the tree in the case of citrus fruits, olives or other types and varieties of pome, stone and nuts. The same mechanism, that is to say the promotion of the formation of separating tissue between the fruit or leaf and shoot part of the plants, is also essential for a well controllable defoliation of useful plants, in particular cotton.

In addition, the shortening of the time interval in which the individual cotton plants ripen leads to increased fiber quality after the harvest. The compounds I or the herbicidal compositions comprising them can be sprayed or atomized, for example in the form of directly sprayable aqueous solutions, powders, suspensions, including high-strength aqueous, oily or other suspensions or dispersions, emulsions, oil dispersions, pastes, dusts, sprays or granules , Dusting, scattering or pouring. The application forms depend on the purposes; in any case, they should ensure the finest possible distribution of the active compounds according to the invention.

The following are essentially considered as inert additives: mineral oil fractions of medium to high boiling point, such as kerosene or diesel oil, furthermore coal tar oils as well as oils of vegetable or animal origin, aliphatic, cyclic and aromatic hydrocarbons, e.g. Paraffin, tetrahydronaphthalene, alkylated naphthalenes or their derivatives, alkylated benzenes or their derivatives, alcohols such as methanol, ethanol, propanol, butanol, cyclohexanol, ketones such as cyclohexanone or strongly polar solvents, e.g. B. amines such as N-methylpyrrolidone or water. Aqueous use forms can be prepared from emulsion concentrates, suspensions, pastes, wettable powders or water-dispersible granules by adding water. To prepare emulsions, pastes or oil dispersions, the 2-phenylpyridines I as such or dissolved in an oil or solvent can be homogenized in water by means of wetting agents, adhesives, dispersants or emulsifiers. However, it is also possible to prepare concentrates consisting of an active substance, wetting agent, tackifier, dispersant or emulsifier and possibly solvent or oil, which are suitable for dilution with water.

The surface-active substances are the alkali metal, alkaline earth metal and ammonium salts of aromatic sulfonic acids, for example lignin, phenol, naphthalene and dibutylnaphthalenesulfonic acid, and of fatty acids, alkyl and alkylarylsulfonates, alkyl, lauryl ether and fatty alcohol sulfates, and salts of sulfated hexa- , Hepta- and octadecanols as well as fatty alcohol glycol ether, condensation products of sulfonated naphthalene and its derivatives with formaldehyde, condensation products of naphthalene or naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ether, ethoxylated isooctyl, octyl or nonylphenyl glycolphenyl, alkylphen - Aryl polyether alcohols, isotridecyl alcohol, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ether or polyoxypropylene alkyl ether, lauryl alcohol polyglycol ether - acetate, sorbitol ester, lignin sulfite waste liquor or methyl cellulose. Powders, materials for broadcasting and dusts can be prepared by mixing or grinding the active substances together with a solid carrier.

Granules, e.g. Coated, impregnated and homogeneous granules can be produced by binding the active ingredients to solid carriers. Solid carriers are mineral soils such as silicas, silica gels, silicates, talc, kaolin, limestone, lime, chalk, bolus, loess, clay, dolomite, diatomaceous earth, calcium and magnesium sulfate, magnesium oxide, ground plastics, fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, Urea and vegetable products such as flour, tree bark, wood and nutshell flour, cellulose powder or other solid carriers.

The concentrations of the active ingredients I in the ready-to-use preparations can be varied over a wide range. The formulations generally contain 0.001 to 98% by weight, preferably 0.01 to 95% by weight, of at least one active ingredient. The active ingredients are used in a purity of 90% to 100%, preferably 95% to 100% (according to the NMR spectrum). The compounds I according to the invention can be formulated, for example, as follows:

I 20 parts by weight of the active ingredient Example No. 9 are dissolved in a mixture consisting of 80 parts by weight of alkylated benzene, 10 parts by weight of the adduct of 8 to 10 moles of ethylene oxide and 1 mole of oleic acid-N-monoethanolamide, 5 parts by weight of calcium salt of dodecylbenzenesulfonic acid and 5 parts by weight of Addition product of 40 moles of ethylene oxide with 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and finely distributing it therein, an aqueous dispersion is obtained which contains 0.02% by weight of the active ingredient.

II 20 parts by weight of the active ingredient Example No. 8 are dissolved in a mixture consisting of 40 parts by weight of cyclohexanone, 30 parts by weight of isobutanol, 20 parts by weight of the adduct of 7 mol of ethylene oxide and 1 mol of isooctylphenol and 10 parts by weight of the adduct of

There are 40 moles of ethylene oxide with 1 mole of castor oil. Pouring the solution into 100,000 parts by weight of water and finely distributing it therein gives an aqueous dispersion which comprises 0.02% by weight of the active ingredient. III 20 parts by weight of the active ingredient Example No. 6 are dissolved in a mixture consisting of 25 parts by weight of cyclohexanone, 65 parts by weight of a mineral oil fraction with a boiling point of 210 to 280 ° C. and 10 parts by weight of the adduct of 40 moles of ethylene oxide and 1 mole of castor oil . Pouring the solution into 100,000 parts by weight of water and finely distributing it therein gives an aqueous dispersion which comprises 0.02% by weight of the active ingredient.

IV 20 parts by weight of the active ingredient Example No. 9 are with

3 parts by weight of the sodium salt of diisobutylnaphthalenesulfonic acid, 17 parts by weight of the sodium salt of lignosulfonic acid from a sulfite waste liquor and 60 parts by weight of powdered silica gel are mixed well and ground in a hammer mill. By finely distributing the

Mixture in 20,000 parts by weight of water contains a spray mixture which contains 0.1% by weight of the active ingredient.

V 3 parts by weight of the active ingredient Example No. 14 are mixed with 97 parts by weight of finely divided kaolin. In this way a dust is obtained which contains 3% by weight of the active ingredient.

VI 20 parts by weight of the active ingredient example no. 8 are mixed with 2 parts by weight of calcium salt of dodecylbenzenesulfonic acid, 8

Parts by weight of fatty alcohol polyglycol ether, 2 parts by weight of sodium salt of a phenol-urea-formaldehyde condesate and 68 parts by weight of a paraffinic mineral oil. A stable oily dispersion is obtained.

VII 1 part by weight of the active ingredient Example No. 6 is dissolved in a mixture consisting of 70 parts by weight of cyclohexanone, 20 parts by weight of ethoxylated isooctylphenol and 10 parts by weight of ethoxylated castor oil. A stable emulsion concentrate is obtained.

VIII 1 part by weight of the active ingredient example No. 14 is dissolved in a mixture consisting of 80 parts by weight of cyclohexanone and 20 parts by weight of Wettol® EM 31 (non-ionic emulsifier based on ethoxylated castor oil). A stable emulsion concentrate is obtained.

The herbicidal compositions or the active compounds can be applied pre- or post-emergence. If the active substances are less compatible for certain crop plants, application techniques can be used in which the herbicidal compositions are sprayed with the aid of sprayers, that the leaves of the sensitive crop plants are not hit, if possible, while the active ingredients get onto the leaves of unwanted plants growing underneath or the uncovered floor area (post-directed, lay-by).

Depending on the control target, the season, the target plants and the growth stage, the active compound application rates are 0.0005 to 3.0, preferably 0.0005 to 1.0 kg / ha of active substance (as described above)

To broaden the spectrum of activity and to achieve synergistic effects, the 2-phenylpyridines I can be mixed with numerous representatives of other herbicidal or growth-regulating active compound groups and applied together. For example, 1, 2, 4-thiadiazoles, 1, 3, 4-thiadiazoles, amides, aminophosphoric acid and their derivatives, aminotriazoles, anilides, (het) -aryloxyalkanoic acid and their derivatives, benzoic acid and their derivatives, benzothiadiazinones, 2-aroyl come as mixing partners -l, 3-cyclohexanediones, hetaryl aryl ketones, benzylisoxazolidinones, meta-CF3-phenyl derivatives, carbamates, quinolinic acid and their derivatives, chloroacetanilides, cyclohexane-1, 3-dione derivatives, diazines, dichloropropionic acid and their derivatives for dihydrobenes , Dihydrofuran-3-ones, dinitroanilines, dinitrophenols, diphenyl ethers, dipyridyls, halocarboxylic acids and their derivatives, ureas, 3-phenyluracils, imidazoles, imidazolinones, N-phenyl-3, 4, 5, 6-tetrahydrophthalimides, oxadiazoles, oxiranes, pheniranes Aryloxy- or heteroaryloxyphenoxypropionic acid esters, phenylacetic acid and its derivatives, phenylpropionic acid and its derivatives, pyrazoles, phenylpyrazoles, pyridazines, pyridinecarboxylic acid and their derivatives, pyridyl ether, p ulfonamides, sulfonylureas, triazines, triazinones, triazolinones, triazolecarboxamides, uracils.

It may also be useful to apply the compounds I alone or in combination with other herbicides, mixed with other crop protection agents, for example with agents for controlling pests or phytopathogenic fungi or bacteria. Also of interest is the miscibility with mineral salt solutions, which are used to remedy nutritional and trace element deficiencies. Non-phytotoxic oils and oil concentrates can also be added.

Production of intermediates II

example 1

3 -Fluor -2 -phenylthio- 5-trifluoromethylpyridine 59.6 g (0.326 mol) of 2,3-difluoro-5-trifluoromethylpyridine were converted into 37.7 g (0.338 mol) of 98.7% thiophenol and 2.1 mg ( 0.01 mol%) copper powder and

Stirred for 2 hours at 156-164 ° C. After cooling, the residue was taken up in methylene chloride, washed with 0.5N sodium hydroxide solution and with water, dried over magnesium sulfate and concentrated in vacuo. 88.9 g (100% of theory) of the title compound were obtained 1, 5539.

Example 2

5-chloro-3-fluoro-2-phenylthio-pyridine

Starting from 93 g (0.508 mol) of 2,3-difluoro-5-chloropyridine, 58.8 g (0.5276 mol) of 98.7% thiophenol and 3.2 mg (0.01 mol%) of copper powder were obtained after stirring for 1.5 h in a pressure apparatus at 185 ° C. and working up according to Example 1, 121.5 g (99.9% of theory) of the title compound as a colorless oil. 1H NMR (ppm, d ₆ DMSO) 8.35 (s / lH), 8.05 (d / lH), 7.4-7.6 (m / 5H).

Example 3

3 - fluoro-3-phenylsulfinyl - 5 - rifluoromethylpyridine

20 g (0.0693 mol) of 95% 3-fluoro-2-phenylthio-5-trifluoromethyl-pyridine were placed in 100 ml of glacial acetic acid and 20 ml of trifluoroacetic acid and within 5 min. 5.64 g (0.083 mol) of 50% hydrogen peroxide are added with stirring at 22 ° C. and the mixture is stirred at 22 ° C. for 10 h. The reaction mixture was poured into 1 liter of ice water, extracted with methylene chloride and the organic phase washed with saturated sodium bicarbonate solution and with water. After drying, filtering through silica gel and concentrating in vacuo, 19.1 g (95.4% of theory) of the title compound were obtained

Example 4

3-fluoro-2-phenylsulfonyl -5-trifluoromethylpyridine

63.2 g (0.1145 mol) of 13.5% sodium hypochlorite were in 4 portions each within 10 min. added with stirring at 25-30 ° C. to a mixture of 13.6 g (0.0498 mol) of the compound from Example 5 in 85 ml of water and 60 ml of glacial acetic acid and stirred for a total of 2.5 h. The reaction mixture was added to 1 1 of ice water, extracted with methylene chloride and the organic phase washed with saturated sodium bicarbonate solution and with water. After drying and concentration in vacuo, 15.1 g (98.9% of theory) of the title compound of mp 82-83 ° C. were obtained.

5 Example 5

5-chloro-3-fluoro-2-phenylsulfinyl-pyridine

33.8 g (0.497 mol) of 50% hydrogen peroxide were within 10 15 min. with stirring at 23-28 ° C to a solution of 119 g

(0.497 mol) of the compound from Example 6 in 500 ml of glacial acetic acid and 150 ml of trifluoroacetic acid and stirred at 23 ° C for 14 h. The reaction mixture was poured onto 2 l of ice water and extracted with methylene chloride and the organic phase was washed with saturated sodium bicarbonate solution and with water. After concentration, 123.5 g (97.3% of theory) of the title compound were obtained as colorless crystals. After stirring with ether / pentane 2: 8, 116.1 g (91.6% of theory) of melting point 77-78 ° C. remained.

20 Preparation of the phenylpyridines I

Example 6

3-fluoro-2- (4-chloro-2-fluoro-5-methoxypheny1) 5- trifluoromethyl-25 pyridine [Table 1, la 1]

A Grignard solution, prepared from 16.96 g (0.0708 mol) of l-bromo-4-chloro-2-fluoro-5-methoxybenzene and 1.98 g (0.0813 mol) of magnesium shavings in 60 ml of THF was removed within 20 min . at 24 - 36 ° C

30 with stirring and gentle cooling to a solution of 17.8 g

(0.0616 mol) 3-fluoro-2-phenylsulfinyl-5-trifluoromethylpyridine in 45 ml THF. After 4 hours of stirring at 24 ° C., the reaction mixture was concentrated in vacuo, taken up in methylene chloride and successively with 1N hydrochloric acid, 1N sodium hydroxide solution and with water

35 extracted and concentrated. The residue was 45 min. stirred in 1N sodium hydroxide solution at 95 ° C and then concentrated to a quarter at 300 mbar. It was partitioned between methylene chloride and water, the organic phase was dried, sucked through a suction filter with silica gel and concentrated in vacuo. 8.7 g (43.7% of theory) were obtained.

40 Th.) Of the title compound of mp 79 - 80 ° C.

Example 7

2 -Chlor -4 -fluor- 5- (3 -fluor- 5- trifluoromethylpyridin-2-yl) -phenol 45 [Table 1, la. 249] 8.5 g (0.0263 mol) of 3-fluoro-2- (4-chloro-2-fluoro -5-methoxyphenyl) -5-trifluoromethylpyridine were added with stirring to 110 ml of 47% hydrobromic acid and under for 2 hours Reflux cooked. After cooling, the clear solution was poured onto 500 ml of water and extracted with methylene chloride. The organic phase was extracted with 1N sodium hydroxide solution, the extract acidified and extracted with ethyl acetate. After drying and concentrating, 6.7 g (82.1% of theory) of the title compound of

Mp 94-96 ° C.

Example 8

(R) -2- (2-chloro-4-fluoro-5 (3-fluoro-5-trifluoromethylpyridin-2-yl) phenoxy) propionic acid methyl ester [Table 1, la. 54]

A mixture of 0.62 g (0.002 mol) of the compound from Example 7, 0.29 g (0.0024 mol) of methyl S- (-) -2-chloropropionate and 0.55 g (0.004 mol) of potassium carbonate powder in 20 ml of DMF was stirred for 1.5 h at 60-70 ° C under HPLC control. After cooling, 100 ml of water were added and 3 times with methyl tert. -butyl ether extracted. The organic phase was dried, suction filtered through silica gel and concentrated in vacuo. 0.78 g (98.6% of theory) of the title compound were obtained as a viscous resin. NMR (360 MHz, CDC1 ₃ ): 7.75 d / 1 (Pyr), 8.8 s / 1 (Pyr), 7.18 d / 1 (Ph), 7.25 m / 1 (Ph), 4 , 8 q / 1 (CH), 3.75 s / 1 (0-CH ₃ ), 1.7 d / 3 (CH ₃ ). After the addition of TFAE shift reagent, the enantiomer ratio was R: S = 93: 7.

Example 9

(R) -2- (2-chloro-4-fluoro-5 (3-fluoro-5-trifluoromethylpyridine -2 -yl) phenoxy) propionic acid isobutyl ester [Table 1, la. 265]

According to the method of example 8, starting from 4.7 g (0.0152 mol) of the compound from example 7, 3.0 g (0.0182 mol) of isobutyl L-chloropropionate and 4.2 g (0.05 03 mol) of potassium carbonate powder 6.5 g (97.8% of theory) of the title compound with n = 1.5061.

Example 10

(R) -2- (2-chloro-4-fluoro-5- (3 - fluoro-5-trifluoromethylpyridin-2-yl) - phenoxy) propionic acid [Table 1, la. 261]

2.0 g (0.0046 mol) of the compound from Example 9 were stirred for 3 hours at 80 ° C. in a mixture of 35 ml of glacial acetic acid and 15 ml of 2N hydrochloric acid. After cooling, was between methylene chloride and Distributed water, the organic phase dried and concentrated. 1.6 g (91.7% of theory) of the title compound of mp 48-50 ° C. were obtained.

Example 11

R-2- (2-chloro-4-fluoro-5- (3-fluoro-5-trifluoromethyl) pyridin-2-yl) phenoxy) propionic acid chloride

1.0 g (0.0026 mol) of the compound from Example 10 and 0.5 g

(0.0042 mol) of thionyl chloride in 10 ml of 1,2-dichloroethane were stirred at 83 ° C. for 2 h. After concentration of the reaction mixture, 1.0 g (95.4% of theory) of the title compound was obtained as a colorless oil.

Example 12

R-2- (2-chloro-4-fluoro -5 - (3-fluor- 5 - trifluoromethylpyridin- 2 -yDphe- noxy-propionic acid propargylic ester [Table 1, la. 266]

A mixture of 0.13 g (0.0013 mol) of triethylamine and 1 ml

Propargyl alcohol was added at 20-29 ° C. with stirring to a solution of 0.5 g (0.00125 mol) of the compound from Example 11 in 10 ml of 1,2-dichloroethane and stirred at 23 ° C. for 1 hour. The reaction mixture was partitioned between methylene chloride and water and the organic phase was dried. After concentration in vacuo, 0.5 g (95.3% of theory) of the title compound was obtained as a colorless resin.

H-NMR (270 MHz, CDC1 ₃ ) 7.75 d / 1 (Pyr), 8.8 s / 1 (Pyr.). 7.18 d / 1 (Ph), 7.25 m / 1 (Ph), 4.85 q / 1 (CH), 4.75 d / 2 (CH ₂ ), 2.4 m / 1 (CH) , 1.7 d / 3 (CH ₃ )

Example 13

2-chloro-4-fluoro-5- (3-fluoro-5-trifluoromethylpyridin-2-yl) -phenyl-propargyl ether [Table 1, la. 5]

A mixture of 0.25 g (0.808 mmol) of the compound from Example 7, 0.12 g (0.97 mmol) of propargyl bromide and 0.22 g (1.62 mmol) of potassium carbonate powder in 10 ml of DMF was added for 2 hours Stirred 65 - 70 ° C. After cooling, 50 ml of water were added, 3 times with methyl tert. -butyl ether extracted and dried. After concentration, 0.28 (100% of theory) of the title compound of mp 68-70 ° C. was obtained. Example 14

5-chloro-3-fluoro-2- (4-chloro-2-fluoro-5-methoxyphenyl) pyridine [Table 1, la. 63]

A Grignard solution of 12.9 g (0.049 mol) of 4-chloro-2-fluoro-5-methoxyphenylmagnesium bromide in 60 ml of THF was added within 10 min. added to a solution of 10 g (0.0392 mol) of 5-chloro-3-fluoro-2-phenylsulfinyl-pyridine in 150 ml of THF while stirring at 23-30 ° C. and stirred at 23 ° C. for 4 h. The reaction mixture was concentrated in vacuo, taken up in methylene chloride and extracted successively with 1N hydrochloric acid, 1N sodium hydroxide solution and with water and dried. After suction filtration over a suction filter with silica gel, concentration, stirring with pentane, suction filtration and drying, 5.7 g (50.1% of theory) of the title compound of mp. 120-122 ° C.

Examples of use (herbicidal activity)

The herbicidal activity of the 2-phenylpyridines of the formula I was demonstrated by greenhouse tests:

Plastic pots with loamy sand with about 3.0% humus served as the culture vessels. The seeds of the test plants were sown separately according to species.

In pre-emergence treatment, the active ingredients suspended or emulsified in water were applied directly after sowing using finely distributing nozzles. The vessels were lightly sprinkled to promote germination and growth, and then covered with clear plastic covers until the plants had grown. This cover causes the test plants to germinate evenly, unless this was affected by the active ingredients.

For the purpose of post-emergence treatment, the test plants, depending on the growth habit, were first grown to a height of 3 to 15 cm and only then treated with the active ingredients suspended or emulsified in water. For this purpose, the test plants were either sown directly and grown in the same containers or they were first grown separately as seedlings and transplanted into the test containers a few days before the treatment. The application rate for post-emergence treatment was 1.9 and 0.9 g / ha a. S.

The plants were kept at temperatures of 10 - 25 ° C or 20 - 35 ° C depending on the species. The trial period lasted 2 to 4 weeks. During this time, the plants were cared for, and their response to each treatment was evaluated.

Evaluation was carried out on a scale from 0 to 100. 100 means no emergence of the plants or complete destruction of at least the aerial parts and 0 means no damage or normal growth.

The plants used in the greenhouse experiments are composed of the following types:

Examples 8 and 9 according to the invention listed in Table C were compared with the corresponding compounds from WO 95/02580.

Table C: Comparison of compounds for determining the herbicidal activity in greenhouse tests using the post-emergence method

The comparison showed a significantly higher herbicidal activity of the compounds according to the invention with better tolerance in crop plants such as rice.

Examples of use (desiccative / defolian effectiveness)

Young, 4-leafed (without cotyledons) cotton plants served as test plants, which were grown under greenhouse conditions (relative humidity 50 to 70%; day / night temperature 27/20 ° C.).

The young cotton plants were drip-treated with aqueous preparations of the active ingredients (with the addition of 0.15% by weight of the fatty alcohol alkoxylate Plurafac® LF 700, based on the spray mixture). The amount of water applied was the equivalent of 1000 l / ha. After 13 days, the number of leaves dropped and the degree of defoliation in% were determined.

No leaf infestation occurred in the untreated control plants.

Claims

claims

1. Substituted 2-phenylpyridines of the formula I.

in which the substituents and index m have the following meanings:

m 0 or I;

R ¹ halogen, -C-C ₄ haloalkyl, C1-C4 haloalkoxy,

Cι-C ₄ alkylthio, Cι-C alkylsulfinyl, Ci-C ₄ alkylsulfonyl, C ₁ -C haloalkylthio or cyano;

R ^{2 is} fluorine or trifluoromethyl;

R ^{3 is} hydrogen or halogen;

R ⁴ halogen or cyano;

R ⁵ CO ₂ R ⁶ , OR ⁷ , SR ⁷ , C (R ⁸ ) = N-0-R ⁷ or C (R ⁸ ) = C (R ⁸ ) -CO-OR ⁶ , where

R ^{6 is} hydrogen, an unsubstituted or halogen-substituted Ci-Cβ-alkyl, C ₃ -C ₆ alkenyl or C ₃ -C ₆ alkynyl radical; C ₁ -C ₄ alkoxy-Ci -C ₄ -alkyl, -C-C ₆ -alkoxy-carbonyl-Cι-C ₄ -alkyl, C ₃ -C ₄ -alkenyloxycarbonyl -Cχ-C ₄ -alkyl, C - C ₄ alkynyloxycarbonyl -C ₁ -C ₄ alkyl or

C ₁ -C ₄ alkoxy- (Ci -C ₄ alkoxy) carbonyl -C ₁ -C ₄ alkyl;

R ^{7 can have} the meaning of R ⁶ or for CH ₂ -C0 ₂ [-C -alkylene] -C0 ₂ R ⁹ and CH [C ₁ -C ₄ -alkyl] -C0 ₂ - [-C-C ₄ -alkylene ] -C0 ₂ R ⁹ ;

R ^{8 is} hydrogen, halogen or C ₁ -C ₄ alkyl and

R ^{9 represents} hydrogen or C ₁ -C ₄ alkyl, and the agriculturally useful salts of the compounds I.

2. Substituted 2-phenylpyridines of formula I according to claim 1, wherein the substituents and index m have the following meanings:

m 0,

R ¹ -C ₃ -C ₃ fluoroalkyl, chlorine, methylsulfonyl or cyano;

R ^{2 is} fluorine or trifluoromethyl;

R ³ fluorine or chlorine;

R ⁴ chlorine;

R ⁵ C0 ₂ R ⁶ , OR ⁷ or SR ⁷ , where

R ^{6 is} hydrogen, -CC ₅ alkyl, C ₃ -C ₄ -alkenyl, 3-chloroprop-2-ene, C ₃ -C ₄ -alkynyl, -C-C ₃ alkoxy -CC-C ₂ alkyl , Ci - C ₆ alkoxycarbonyl -Ci - C ₂ - alkyl, propargyloxycarbonyl ₁ - Ci - C - alkyl, C - C ₃ alkoxy- Ci - C ₃ - alkoxycarbonyl - Ci - C - alkyl means;

R ^{7 can have} the meaning of R ⁶ or for CH ₂ -C0 ₂ [-C-C ₂ -alkylene] C0 ₂ R ⁹ and CH [-C-C ₂ -alkyl] -C0 ₂ [-C-C ₂ -alkylene] C0 ₂ R ⁹ is;

R ^{8 is} hydrogen, halogen or C ₁ -C ₄ alkyl and

R ⁹ denotes hydrogen or C1-C ₄ alkyl,

and the agriculturally useful salts of the compounds I.

3. Process for the preparation of substituted 2-phenylpyridines - of the formula I according to claim 1, characterized in that substituted pyridines of the formula II

in which R ¹ and R ^{2 have} the meaning given in claim 1,

n denotes 1 or 2 and

i Z represents an aliphatic radical or an aryl radical,

with an aryl compound of formula III or IV

in which X is halogen and R ³ , R ⁴ and R ^{5 have} the meaning given in Claim 1.

4. Substituted thiopyridines of the general formula II

in the

n 0, 1 or 2;

R 1 -C ₃ fluoroalkyl, chlorine, methylsulfonyl or cyano;

R ² fluorine or trifluoromethyl and

Z is an unsubstituted or substituted by halogen, _{Cι-C4-alkoxy,} Cι-C hydroxyalkyl, C ₁ -C ₄ alkoxycarbonyl, di _(Cι-C4 alkyl amino) carbonyl, cyano or by nitro 0 Cι- Cιo-alkyl, C ₂ -Cιo-alkenyl or C ₂ -Cιo-alkynyl radical, a C ₃ -C ₈ cycloalkyl radical or one unsubstituted in the phenyl or naphthyl part or by halogen, Cι-C ₃ alkyl, Cι-C ₃ -alkoxy, trifluoromethyl, cyano or nitro substituted C- _1. -C ₄ -alkyleneph.enyl, phenyl or 5 naphthyl radical.

5. Substituted thiopyridines of the general formula II

in the

n 1 or 2;

Ri trifluoromethyl, chlorine, methylsulfonyl or cyano;

R ² fluorine or trifluoromethyl and

Z is an unsubstituted or substituted by chlorine or methoxy -CC ₈ alkyl radical, a benzyl or phenyl radical which is unsubstituted in the phenyl part or is substituted by halogen, methyl, Ci-C ₃ alkoxy, trifluoromethyl, cyano or nitro.

6. Herbicidal composition containing a herbicidally effective amount of at least one substituted 2-phenylpyridine of the formula I or an agriculturally useful salt of I, according to claim 1, and at least one inert liquid and / or solid carrier and, if desired, at least one adjuvant.

7. Agent for the desiccation and / or defoliation of plants, containing a desiccant and / or defoliantly effective amount of at least one substituted 2-phenylpyridine of the formula I or an agriculturally useful salt of I, according to claim 1, and at least one inert liquid and / or solid carrier and, if desired, at least one adjuvant.

8. A method for controlling undesirable plant growth, characterized in that a herbicidally effective amount of at least one substituted 2-phenylpyridine of the formula I or an agriculturally useful salt of I, according to claim 1, is allowed to act on plants, their habitat or on seeds.

9. A process for the desiccation and / or defoliation of plants, characterized in that a desiccant and / or defoliantly effective amount of at least one substituted 2-phenylpyridine of the formula I or an agriculturally useful salt of I, according to claim 1, can act on plants.