WO1999003845A1 - 2-benzoylcyclohexane-1,3-dione derivatives as herbicides and intermediates - Google Patents

Abstract

Compounds of formula (I) wherein: R1 represents a group of formula (II), (III), (IV) or (V) or a corresponding formula (IVa) or (Va) in which the position of the carbonyl group and the group Q are reversed and the double bond in the ring is attached to the carbon atom attached to the group Q; R3 represents a 5-membered heteroaromatic ring of formula (VI) and their use as herbicides.

Description

-BENZOYLCYCLOHEXANE-1.3-DIONE DERIVAΗVES AS HERBICIDES AND INTERMEDIATES

This invention relates to novel 2-benzoylcyclohexane-l,3-dione and related derivatives, compositions containing them, processes for their preparation, intermediates in their preparation and their use as herbicides.

Herbicidal 2-benzoylcyclohexane-l,3-diones are described in US Publication numbers 4,780,127 and 5,536,703, and WO 9626192 as well as EP 0666254. amongst other references. However none of the above publications disclose or suggest the presence of an aromatic heterocyclic ring linked by a ring nitrogen atom (optionally via a methylene) to the benzoyl ring.

The present invention provides 2-benzoylcyclohexane-l,3-dione derivatives of formula (I):

(I) wherein: R.1 represents a group of formula (II), (III), (IV) or (V):

(IV) (V) or a corresponding formula (IVa) or (Va):

(IVa) (Va) in which the position of the carbonyl group and the group Q are reversed and the double bond in the ring is attached to the carbon atom attached to the group Q;

R² represents :- halogen; lower alkyl which is substituted by one or more groups -OR¹⁰; a cycloalkyl group containing from three to six carbon atoms; or a group selected from nitro, cyano, -CO2R¹⁰, -NR^R¹ 1 , -S(O)_pR¹²,

-O(CH₂)_mOR¹⁰, -COR¹⁰, -N(Rl 3)SO₂R¹², -OR¹², -OH, -OSO₂R¹²,

-(CR¹⁴R¹⁵)_tS(O)_qR¹², -CONR^R¹1, -N(R¹³)-C(Z)=Y,

-C(R¹⁴R¹⁵)NR¹³R¹⁶, -CH₂P(O)R^10aR^10b, R¹⁷, SF5 and benzyl optionally substituted by from one to five groups R ^ which may be the same or different; or two groups R², together with adjacent carbon atoms of the phenyl ring form a second phenyl ring or a 5- or 6-membered saturated or unsaturated heterocyclic ring which is fused to the first ring and contains one or two oxygen or sulphur atoms and is optionally substituted by one or more halogen , lower alkyl, lower haloalkyl or lower alkoxy groups, or one of the ring carbon atoms of the heterocyclic ring forms part of a carbonyl group or an oxime or lower alkoxyimine derivative thereof; (examples of the optionally substituted fused ring systems when formed include thiochroman, chroman, 2H-thiochromene, 2H-chromene, 4H-thiochromene, 4H-chromene, isothiochroman, isochroman, isothiochromene, isochromene, 1,3-benzodithiole, 1,3- benzodioxole, 1,3-benzoxathiole, 1 ,4-benzodithiin, 1 ,4-benzoxathiin, 1 ,4-benzoxathian, 1,3-benzoxathian, 3,1-benzoxathian and 1,3- benzodithian); n represents zero or an integer from one to three; where n is greater than one the groups R² may be the same or different; m represents one, two or three; p and q represent zero, one or two; t represents one, two, three or four (preferably one); when t is more than one R¹⁴ and R¹ ^ may be the same or different;

X represents -(CR¹⁴R¹⁵)_V-; v represents zero or one;

R³ represents a 5-membered heteroaromatic ring of formula (VI)

— N

(VI) in which D, E, G and J independently represent CR¹^ or a nitrogen atom, with at least one of D, E, G and J representing CR¹^ (when more than one CR ^ group is present they may be the same or different); or two adjacent groups may form a phenyl or a 5- to 7- membered heteroaromatic ring which is fused to the first ring and is optionally substituted by one or more groups R²⁰, and when present the 5- to 7- membered heterocyclic ring may contain from one to four heteroatoms in the ring which may be the same or different selected from nitrogen, oxygen and sulphur; z represents one or two; when z represents two the -XR³ groups may be the same or different;

Q represents hydroxy, lower alkoxy, OR²¹, SR²¹ or SR²²; L represents oxygen or NR ⁴;

R⁴, R^4a, R^4b, R⁵, R^5a, R^5b, R6, R6a _R6b_{5 R}7_{? R}7a _R7b_{? R}8, R^8a, R^8b, R9, R9a _an(\ _R9b represent the same or different groups selected from hydrogen, R¹⁷, -(CH₂)_uCO₂R¹⁴, halogen, cyano, lower alkoxy, -(CH₂)_X- [phenyl optionally substituted by from one to five groups R 8 which may be the same or different], and cycloalkyl containing from three to six carbon atoms optionally substituted by lower alkyl or -S(O)_pR²² ; u represents zero, one or two; x represents zero or one;

RlO and R¹ which may be the same or different, each represents hydrogen or R¹⁷;

R^10a and R ^0b which may be the same or different, each

5 represents lower alkyl or lower alkoxy;

R¹² represents:-

R¹⁷; or a cycloalkyl group containing from three to six carbon atoms; or a group -(CH₂)_W- [phenyl optionally substituted by from one to five groups R^{1 8} which may be the same or different]; l o w represents zero or one;

R ³ represents :- hydrogen, R¹² or OR²²;

R¹⁴ and R¹^ independently represent hydrogen, lower alkyl or lower haloalkyl (preferably containing up to three carbon atoms); 15 R¹⁶ represents -SO₂R¹² or -C(Z)=Y;

R¹⁷ represents :- lower alkyl, lower haloalkyl, lower alkenyl, lower haloalkenyl, lower alkynyl or lower haloalkynyl;

R¹⁸ represents a group selected from halogen, R²³, nitro, cyano, 20 -CO2R¹ °, -S(O)_pR²², -OR²² and -NR¹ OR¹ * ;

R ^ represents :- a group selected from hydrogen, halogen, R²³, nitro, cyano, -CO₂R¹⁰, -S(O)_pR²², -OR²², -NR^R¹ 1 and cyclopropyl;

R²⁰ represents halogen or R ⁷; 25 R²¹ represents phenyl optionally substituted by from one to five groups selected from halogen, lower alkyl, lower haloalkyl, lower alkoxy and nitro;

_R22 represents lower alkyl or lower haloalkyl; R²³ represents a straight- or branched- chain alkyl group 30 containing one to three carbon atoms optionally substituted by one or more halogen atoms;

Y is oxygen or sulphur (preferably Y represents oxygen); Z represents a group selected from R¹⁷, -NR² R²^, -SR¹² and -OR¹²; 35 R²⁴ and R²^ independently represent hydrogen or R ²; and agriculturally acceptable salts and metal complexes thereof, which possess valuable herbicidal properties.

Compounds of formula (I) may exist in enolic tautomeric forms that may give rise to geometric isomers around the enolic double bond. Furthermore in certain cases the above substituents may contribute to optical isomerism and/or stereoisomerism. All such forms and mixtures are embraced by the present invention.

It is to be understood that in this specification compounds comprising a cyclohexane ring corresponding to formula (IV) or (V) or a precursor thereof include the compounds with the corresponding formula (IVa) or (Va) or precursors thereof.

In the description unless otherwise specified the following terms are generally defined thus:-

'lower alkyl' means a straight- or branched- chain alkyl group having one to six carbon atoms;

'lower haloalkyl' means a straight- or branched- chain alkyl group having one to six carbon atoms, substituted by one or more halogens;

'lower alkoxy' means a straight- or branched- chain alkoxy group having one to six carbon atoms; 'lower haloalkoxy' means a straight- or branched- chain alkoxy group having one to six carbon atoms, substituted by one or more halogens;

'lower alkenyl' means a straight- or branched- chain alkenyl group having two to six carbon atoms; 'lower haloalkenyl' means a straight- or branched- chain alkenyl group having two to six carbon atoms, substituted by one or more halogens;

'lower alkynyl' means a straight- or branched- chain alkynyl group having three to six carbon atoms; 'lower haloalkynyl' means a straight- or branched- chain alkynyl group having three to six carbon atoms, substituted by one or more halogens;

'halogen' means a fluorine, chlorine, bromine or iodine atom. By the term "agriculturally acceptable salts" is meant salts the cations or anions of which are known and accepted in the art for the formation of salts for agricultural or horticultural use. Preferably the salts are water-soluble. Suitable salts with bases include alkali metal (eg. sodium and potassium), alkaline earth metal (eg. calcium and magnesium), ammonium and amine (eg. diethanolamine, triethanolamine, octylamine, morpholine and dioctylmethylamine) salts. Suitable acid addition salts, formed by compounds of formula (I) containing an amino group, include salts with inorganic acids, for example hydrochlorides, sulphates, phosphates and nitrates and salts with organic acids, for example acetic acid.

By the term "metal complexes" is meant compounds wherein Q represents hydrogen (or a tautomer thereof) in which one or more of the oxygen atoms of the 2-benzoylcyclohexane-l ,3-dione derivatives of formula (I) act as chelating agents to a metal cation. Examples of such cations include zinc, manganese, cupric, cuprous, ferric, ferrous, titanium and aluminium. The compounds of the invention, in certain aspects of their properties, for example their high levels of herbicidal activity, show advantageous properties over known compounds.

Compounds wherein one XR³ group is present are preferred

(preferably the XR³ group is at the 2- or 4- position of the phenyl ring). Compounds wherein X represents -(CH )_V- are preferred

(compounds in which v represents zero are especially preferred).

Compounds wherein Q represents hydroxy or -S-phenyl are preferred (compounds in which Q represents hydroxy are especially preferred). Compounds of formula (I) in which the 2- and 4-positions of phenyl are substituted are also preferred.

Preferably R³ is selected from pyrazol-1-yl, imidazol-1-yl,

1,2,4-triazol-l-yl, 1,2,3-triazol-l-yl, l,2,3-triazol-2-yl, 1,2,3,4-tetrazol-l-yl and benzimidazol-1-yl (1,2,3-triazol-l-yl, l,2,3-triazol-2-yl are more preferred, and 1,2,4-triazol-l-yl is most preferred).

Preferably R³ is a ring of formula (VI) wherein R¹^ represents hydrogen, halogen or R²³.

In formula (I) above, preferably the 5- and 6- positions of phenyl are unsubstituted.

Preferably R represents a group of formula (II). Preferably R² represents halogen, a straight- or branched- chain alkyl group containing up to four carbon atoms optionally substituted by one or more halogen atoms; or a group selected from nitro, cyano, -S(O)pR¹², -OR¹², -CH₂S(O)_qR¹² wherein R¹² represents lower alkyl or lower haloalkyl; or benzyl optionally substituted by -S(O)_pR²² wherein R²² represents lower alkyl; or two groups R² together with adjacent carbon atoms of the phenyl ring form a second phenyl ring. Preferably n represents one or two.

A preferred class of compounds of formula (I) above are those wherein:-

R¹ is selected from: a group of formula (II) wherein R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ represent hydrogen or lower alkyl; or a group of formula (III) wherein R^4b, R^5b, R^6b, R^7b, R^8b and R^9b represent hydrogen or lower alkyl; or a group of formula (IV) wherein R^8a and R^9a represent hydrogen or lower alkyl; and a group of formula (V) wherein R ^a, R^^a, R6a _and _R7a represent hydrogen or lower alkyl, and L represents NH; Q represents hydroxy or -S-phenyl;

R² represents :- a straight- or branched- chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms; or a group selected from halogen, nitro, -S(O)_pR¹², -OR¹², -CH₂S(O)_qR¹², -CH2NR¹³Rl6, -N(R¹ )SO₂R¹², -N(R¹³)CO₂R¹² and benzyl optionally substituted by -S(O)_pR²²; n represents zero, one or two; X represents -(CH₂)_V-;

R³ represents a 5 -membered heteroaromatic ring of formula (VI) which is selected from pyrazol-1-yl, imidazol-1-yl, 1,2,4-triazol-l-yl,

1,2,3-triazol-l-yl, l,2,3-triazol-2-yl, 1,2,3,4-tetrazol-l-yl and benzimidazol-1-yl, the ring systems of which are substituted by one or two R¹⁹ groups; z represents one; R¹² and R¹³ independently represent lower alkyl or lower haloalkyl;

R¹⁶ represents -SO₂R¹² or CO₂R¹²;

R¹⁹ represents hydrogen or a straight- or branched- chain alkyl group containing up to three carbon atoms; and

R²² represents lower alkyl.

A particularly preferred class of compounds of formula (I) above are those wherein :-

R¹ is selected from: a group of formula (II) wherein R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ represent hydrogen, methyl or ethyl; or a group of formula (III) wherein R^4b, R^5b, R^6b, R^7b, R^8b and R ^b represent hydrogen, methyl or ethyl; or a group of formula (IV) wherein R^8a and R^9a represent hydrogen, methyl or ethyl; and a group of formula (V) wherein R^4a, R^^a, R6a nd _R7a represent hydrogen, methyl or ethyl, and L represents NH; Q represents hydroxy or -S-phenyl; R² represents :- halogen, a straight- or branched- chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms; or a group selected from -S(O)_pCH3, -CH₂S(O)_qCH3, -OCH3 and benzyl optionally substituted by -S(O)_pCH3;

X represents a bond; R³ represents a pyrazol-1-yl, imidazol-1-yl, 1,2,3-triazol-l-yl, l ,2,3-triazol-2-yl, 1,2,4-triazol-l-yl or 1,2,3,4-tetrazol-l-yl ring substituted by one or two R¹ groups, wherein R¹⁹ represents hydrogen, halogen or optionally halogenated methyl; z represents one; and n represents 0, 1 or 2.

A further particularly preferred class of compounds of formula (I) above are those wherein: -

R¹ represents a group of formula (II) wherein R⁴, R^, R6, R⁷, R⁸ and R⁹ represent hydrogen, methyl or ethyl; Q represents hydroxy or -S-phenyl; R² represents :- halogen, a straight- or branched- chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms; or a group selected from -S(O)_pCH3, -CH₂S(O)_qCH3, -OCH3 and benzyl optionally substituted by -S(O)_pCH3;

X represents a bond;

R³ represents a pyrazol-1-yl, imidazol-1-yl, 1,2,3-triazol-l-yl, l,2,3-triazol-2-yl, 1,2,4-triazol-l-yl or 1,2,3,4-tetrazol-l-yl ring substituted by one or two R¹⁹ groups, wherein R¹⁹ represents hydrogen, halogen or optionally halogenated methyl; z represents one; and n represents 0, 1 or 2.

A further particularly preferred class of compounds of formula (I) above are those wherein: - R¹ represents a formula (II) wherein wherein R⁴, R^, R⁸ and R⁹ represent hydrogen;

R6 and R⁷ represent hydrogen or methyl; R² represents :- optionally halogenated methyl; Q represents hydroxy or -S-phenyl;

X represents a bond;

R³ represents a 1,2,4-triazol-l-yl ring; and z and n represent one.

Particularly preferred compounds of the invention include: 2-[4-(l,2,4-triazol-l-yl)-2-trifluoromethylbenzoyl]cyclohexane-

1,3-dione (Compound 1);

3-phenylthio-2-[4-(l,2,4-triazol-l-yl)-2- trifluoromethylbenzoyl]cyclohex-2-ene-l-one (Compound 2); and 5,5-dimethyl-2-[4-(l,2,4-triazol-l-yl)-2- trifluoromethylbenzoyl]cyclohexane-l ,3-dione (Compound 3)

2-[2-chloro-4-( 1 ,2,4-triazol- 1 -yl)benzoyl] cyclohexane- 1 ,3-dione (Compound 31)

2-[2-methyl-4-(l,2,4-triazol-l-yl)benzoyl]cyclohexane-l,3-dione (Compound 32) 2-[2-methylthio-4-( 1 ,2,4-triazol- 1 -yl)benzoyl]cyclohexane- 1 ,3- dione (Compound 42) 5-methyl-2-[4-(l ,2,4-triazol-l -yl)-2- trifluoromethylbenzoyl]cyclohexane-l,3-dione (Compound 88)

5-methyl-2-[2-chloro-4-(l,2,4-triazol-l-yl)benzoyl]cyclohexane- 1,3-dione (Compound 99)

5,5-dimethyl-2-[2-chloro-4-(l,2,4-triazol-l- yl)benzoyl]cyclohexane-l,3-dione (Compound 166).

The following compounds of formula (I) in which R represents a group of formula (II); R⁴, R^, R⁸ and R⁹ represent hydrogen, and the group (XR³)_Z is attached either to the 4-position of the phenyl ring

(Table 1), or to the 2-position of the phenyl ring (Table 2), or to the 3- position of the phenyl ring (Table 3), form part of the present invention.

In the Tables that follow, Me means methyl, Et means ethyl, Pr means propyl, and Ph means phenyl. Where subscripts do not appear in the

Tables it will be understood that in appropriate cases they are present (e.g. CF3 means CF3 etc.).

TABLE 1

TABLE 2

TABLE 3

Compounds of formula (I) may be prepared by the application or adaptation of known methods (i.e. methods heretofore used or described in the literature), for example as hereinafter described.

In the following description where symbols appearing in formulae are not specifically defined, it is to be understood that they are "as hereinbefore defined" in accordance with the first definition of each symbol in the specification.

It is to be understood that in the descriptions of the following processes the sequences may be performed in different orders, and that suitable protecting groups may be required to achieve the compounds sought.

According to a feature of the present invention compounds of formula (I) wherein the various symbols are as defined above and Q represents hydroxy may be prepared by the rearrangement of a compound of formula (VII), (VIII), (IX) or (X):

(IX) (X) wherein the various symbols are as defined above, by reaction with a source of cyanide in the presence of a base. Cyanide sources include metal cyanides for example alkali metal cyanides such as sodium cyanide, hydrogen cyanide, or cyanhydrins of dialkyl ketones preferably acetone cyanhydrin. Generally up to 0.5 equivalent (preferably 0.1 equivalent) of cyanide source is employed. Suitable bases include trialkylamines such as triethylamine, or pyridine or alkali metal carbonates such as potassium carbonate. Generally 1 -4 equivalents (preferably 2 equivalents) of the base is used. Solvents which may be used include toluene, acetonitrile, dichloromethane or preferably 1 ,2- dichloroethane. The reaction is generally performed at a temperature of from 0°C-60°C (generally at 20°C-30°C).

The above ester intermediates of formula (VII), (VIII), (IX) or (X) may be prepared by the reaction of the corresponding cyclohexane- 1,3- dione derivatives of formula (XI), (XII), (XIII) or (XIV) (which are represented here as the enol tautomer forms):

wherein the various symbols are as defined above, with an acid chloride of formula (XV):

wherein R², R³, X, z and n are as defined above. The reaction is generally performed in the presence of a base preferably a trialkylamine such as triethylamine, or an alkali metal carbonate such as potassium carbonate, in a solvent such as dichloromethane, dichloroethane, 5 acetonitrile, N,N-dimethylformamide or tetrahydrofuran. One to 1.1 equivalents of the base is generally employed and the reaction is generally conducted at a temperature of from about -20°C to about 50°C (preferably 0°C to 30°C). Compounds of formula (VII), (VIII), (IX) and (X) are novel and as such constitute a further feature of the invention, l o Optionally the reaction to form a compound of formula (I) by the reaction of a compound of formula (XV) with a compound of formula (XI), (XII), (XIII) or (XIV) to give ester intermediates of formula (VII), (VIII), (IX) or (X), and the subsequent reaction with a source of cyanide may be performed in one pot. In such cases the intermediate esters are 15 not isolated but are treated in situ with the additional base and cyanide source required for the rearrangement process to occur, and according to the above process description.

It is understood that when unsymmetrical diones of formulae (XI), (XII), (XIII) and (XIV) are employed in the above reaction, that the 20 isomeric esters in which the position of the ring carbonyl and ester groups is reversed may be formed, and that the process is applicable for the formation of all such isomeric forms.

According to a further feature of the present invention compounds of formula (I) wherein the various symbols are as defined above and Q 25 represents SR²¹ or SR²² may be prepared by reaction of the corresponding compound of formula (I) wherein Q represents hydroxy with a chlorinating agent, generally oxalyl chloride, in an inert solvent such as dichloromethane and preferably in the presence of a catalyst such as N,N-dimethylformamide and at a temperature of from -20°C to 30 50°C (preferably from 0°C to 30°C) to give the intermediate chloride of formula (I) wherein Q is replaced by a chlorine atom. These intermediates are not generally isolated and are reacted in situ with a thiophenol of formula (XVI) or thiol of formula (XVII):

R²¹SH (XVI) R ²SH (XVII)

35 wherein R²¹ and R²² are as defined above, in the presence of a base such as a trialkylamine, for example triethylamine, in an inert solvent such as dichloromethane or tetrahydrofuran, and at a temperature of from -20°C to 50°C (preferably from 0°C to 30°C).

According to a further feature of the present invention compounds in which p or q is one or two may be prepared by the oxidation of the sulphur atom of the corresponding compounds in which p or q is 0 or 1.

The oxidation of the sulphur atom is generally carried out using for example 3-chloroperoxybenzoic acid in an inert solvent such as dichloromethane at a temperature from -40°C to room temperature. Compounds of formula (XV) may be prepared by the reaction of the corresponding benzoic acid derivative of formula (XVIII):

(XVIII) with a chlorinating agent such as thionyl chloride or oxalyl chloride according to known procedures. Certain benzoic acids of formula (XVIII) are novel and as such constitute a further feature of the invention.

Compounds of formula (XI), (XII), (XIII) and (XIV) are known or may be prepared by known methods.

The following non-limiting Examples illustrate the preparation of compounds of formula (I) and the Reference Examples illustrate the preparation of intermediates in their synthesis. NMR Spectra are recorded as d (ppm) in deuterochloroform as solvent (unless ortherwise stated).

Example 1 To a solution of 3-[4-(l,2,4-triazol-l-yl)-2- trifluoromethylbenzoyloxy]cyclohex-2-en-l-one (2.90g) in acetonitrile was added triethylamine (1.67g) and acetone cyanohydrin (0.3ml) at 20°C. The mixture was stirred for 3 days, evaporated and the residue diluted (ethyl acetate and aqueous citric acid). The organic layer was dried (magnesium sulfate), evaporated and the residue purified by chromatography eluting with ethyl acetate/hexane to give 2-[4-( 1,2,4- triazol-l-yl)-2-trifluoromethylbenzoyl]cyclohexane-l,3-dione as a colourless solid (Compound 1 , 1.75g), NMR 2.06(m,2H), 2.42(t,2H), 2.82(t,lH), 7.36(d,lH), 7.90(m,lH), 8.05(s,lH), 8.15(s,lH), 8.65(s,lH). By proceeding in a similar manner the following compounds were 5 also prepared:

5,5-dimethyl-2-[4-(l ,2,4-triazol-l-yl)-2- trifluoromethylbenzoyl] cyclohexane- 1, 3 -dione (Compound 3), NMR 1.24(6H,s), 2.29(2H,s), 2.68(2H,s), 7.34(lH,d), 7.89(lH,d), 8.05(lH,s), 8.14(lH,s), 8.66(lH,s); 5-methyl-2-[4-(l,2,4-triazol-l-yl)-2- o trifluoromethylbenzoyl]cyclohexane- 1 ,3-dione (Compound 88), NMR

1.12 (d, IH), 1.70 (s, IH), 2.11-2.46 (m, 3H), 2.67-2.80 (m, 2H), 7.36 (d, 1H9, 7.92 (d, IH), 8.08 (s, IH), 8.16 (s, IH), 8.73 (s, IH);

2-[2-chloro-4-( 1 ,2,4-triazol- 1 -yl)benzoyl]cyclohexane- 1 ,3-dione (Compound 31), NMR 2.08 (m, 2H), 2.48 (m, 2H), 2.81 (m, 2H), 7.36 5 (d, IH), 7.67 (d, IH), 7.79 (s, IH), 8.12 (s, IH), 8.60 (s, IH);

5,5-dimethyl-2-[2-chloro-4-(l,2,4-triazol-l- yl)benzoyl]cyclohexane-l,3-dione (Compound 166), NMR 1.43 (s, 6H), 2.35 (s, 2H), 2.68 (s, 2H), 7.37 (d, IH), 7.67 (d, IH), 7.78 (s, IH), 8.12 (s, IH), 8.61 (s, IH); 0 5-methyl-2-[2-chloro-4-(l ,2,4-triazol-l -yl)benzoyl]cyclohexane-

1,3-dione (Compound 99), NMR 1.14 (d, 3H), 1.65 (s, IH), 2.26-2.40 (m, IH), 2.47-2.60 (m, 2H), 2.78-2.92 (m, 2H), 7.36 (d, IH), 7.67 (d, IH), 7.78 (s, IH), 8.12 (s, IH), 8.60 (s, IH);

2-[2-methylthio-4-(l ,2,4-triazol-l-yl)benzoyl]cyclohexane-l,3- 5 dione (Compound 42), NMR 2.0(m,2H), 2.3(m,2H), 2.4(s,2H),

2.7(m,2H), 7.2(d,lH), 7.4(d,lH), 7.6(s,lH), 8.0(s,lH), 8.6(s,lH); and 2- [2-methyl-4-( 1 ,2,4-triazol- 1 -yl)benzoyl]cyclohexane- 1 ,3-dione (Compound 32), NMR 2.0(m,2H), 2.3(s,2H), 2.4(m,2H), 2.8(m,2H), 7.2(d,lH), 7.5(d,lH), 7.6(s,lH), 8.1(s,lH), 8.6(s,lH) . 30 Example 2

To a solution of 2-[4-(l,2,4-triazol-l-yl)-2- trifluoromethylbenzoyl]cyclohexane-l,3-dione (1.42g) in dry dichloromethane was added a catalytic amount of N,N- dimethylformamide followed by oxalyl chloride (0.9ml) dropwise at 35 20°C. The mixture was stirred until a clear solution was obtained and then evaporated. To a suspension of the residue in dry tetrahydrofuran was added thiophenol (0.5 lg) and triethylamine (0.93g) dropwise at 0 °C. The mixture was stirred at 20°C for one day, then aqueous citric acid and ethyl acetate added. The organic layer was dried (magnesium sulfate), evaporated and the residue purified by chromatography eluting with ethyl acetate/hexane to give 3-phenylthio-2-[4-(l ,2,4-triazol-l -yl)-

2-trifluoromethylbenzoyl]cyclohex-2-ene-l-one (Compound 2, 0.93g) as a yellow solid, NMR 1.92(m,2H), 2.36(t,2H), 2.48(t,2H), 7.40- 7.62(m,6H), 7.92(dd,lH), 8.04(d,lH),8.15(s,lH),8.66(s,lH). Reference Example 1 To a suspension of 4-( 1 ,2,4-triazol- 1 -yl)-2-trifluoromethylbenzoic acid (3.32g) and a catalytic amount of N,N-dimethylformamide in dichloromethane was added oxalyl chloride (2.5ml) dropwise at 20°C. The mixture was stirred for 3 hours and evaporated. To a suspension of the residue in dichloromethane was added a solution of 1 ,3- cyclohexanedione ( 1.52g) in dichloromethane and triethylamine (4.16g) dropwise at 0°C. The reaction mixture was warmed to 20°C, stirred for 0.5 hour, diluted (ethyl acetate) and washed with aqueous citric acid. The organic layer was dried (magnesium sulfate), evaporated and the residue purified by chromatography to give 3-[4-(l,2,4-triazol-l-yl)-2- trifluoromethylbenzoyloxy]cyclohex-2-en-l-one as a yellow solid

(3.05g), NMR 2.15(m,2H), 2.50(t,2H), 2.70(t,2H), 6.10(s,lH), 8.03(m,lH), 8.12(d,lH), 8.19(s,lH), 8.22 (s,lH), 8.73(s,lH).

By proceeding in a similar manner the following compounds were also prepared: 5,5-dimethyl-3-[4-(l,2,4-triazol-l-yl)-2- trifluoromethylbenzoyloxy]cyclohex-2-en-l-one, which was used directly in the following stage;

5-methyl-3-[4-(l,2,4-triazol-l-yl)-2- trifluoromethylbenzoyloxy]cyclohex-2-en-l-one, NMR 1.17 (d, 3H), 2.15-2.30 (m, 2H), 2.35-2.75 (m, 3H), 6.08 (s, IH), 8.00-8.27 (m, 4H),

8.78 (s, IH);

5,5-dimethyl-3-[2-chloro-4-(l ,2,4-triazol-l - yl)benzoyloxy]cyclohex-2-en-l-one, NMR 1.18 (s, 6H), 2.35 (s, 2H), 2.60 (s, 2H), 6.08 (s, IH), 7.75 (d, IH), 7.97 (s, IH), 8.10-8.20 (m, 2H), 8.76 (s, IH); 3-[2-chloro-4-(l,2,4-triazol-l-yl)benzoyloxy]cyclohex-2-en-l-one; 5-methyl-3-[2-chloro-4-(l,2,4-triazol-l-yl)benzoyloxy]cyclohex-2-en-l- one;

3-[2-methylthio-4-(l,2,4-triazol-l-yl)benzoyloxy]cyclohex-2-en- 1-one; and

3-[2-methyl-4-( 1 ,2,4-triazol- 1 -yl)benzoyloxy]cyclohex-2-en- 1 - one.

Reference Example 2 To a solution of methyl 4- (l,2,4-triazol-l-yl)-2-trifluoromethylbenzoate (5.07g) in methanol was added aqueous sodium hydroxide (1.50g) at 20°C. The mixture was stirred for 4 hours, partially evaporated and extracted with ether. The aqueous layer was acidified (aqueous citric acid) and extracted with ethyl acetate. The organic layer was dried (magnesium sulfate), and evaporated to give 4-( 1 ,2,4-triazol- 1 -yl)-2-trifluoromefhylbenzoic acid

(3.32g), NMR 8.25(1H), 8.34-8.42(3H), 10.00(s,lH).

By proceeding in a similar manner the following compounds were also prepared:

2-chloro-4-(l,2,4-triazol-l-yl)benzoic acid, NMR 7.71 (d, IH), 7.93 (s, IH), 8.05-8.18 (m, IH), 8.82 (s, IH);

2-methylthio-4-(l ,2,4-triazol-l-yl)benzoic acid, NMR 2.5(s,3H), 7.7(m,2H), 8.0(d,lH), 8.3(s,lH), 9.5(s,lH), 13.2(bs,lH); and

2-methyl-4-(l,2,4-triazol-l-yl)benzoic acid, NMR 2.6(s,3H), 7.8(d,lH), 7.9(s,lH), 8.0(d,lH), 8.3(s,lH), 9.4(s,lH), 13.0(bs,lH). Reference Example 3

To a solution of methyl 4-fluoro-2-trifluoromethylbenzoate (4.95g) in N,N-dimethylformamide was added 1 ,2,4-triazole (2.0g) and potassium carbonate (4.0g) at 20°C and the mixture stirred for 4 hours at 60°C. The mixture was diluted (ether), washed (aqueous citric acid) and dried (magnesium sulfate). The residue was purified by chromatography to give methyl 4-(l,2,4-triazol-l-yl)-2- trifluoromethylbenzoate (5.07g), NMR 3.98(s,3H),7.94- 8.05(2H),8.15(2H),8.71(s,lH).

By proceeding in a similar manner the following compounds were also prepared: methyl 2-chloro-4-(l,2,4-triazol-l-yl)benzoate, NMR 3.97 (s, 3H), 7.68 (d, IH), 7.89 (s, IH), 8.02 (s, IH), 8.14 (s, IH), 8.70 (s, IH); methyl 2-methylthio-4-(l,2,4-triazol-l-yl)benzoate, mpl55- 156°C; and 5 methyl 2-methyl-4-(l,2,4-triazol-l-yl)benzoate, mρl06-107°C.

According to a feature of the present invention, there is provided a method for controlling the growth of weeds (i.e. undesired vegetation) at a locus which comprises applying to the locus a herbicidally effective o amount of at least one 2-benzoylcyclohexane- 1 ,3 -dione derivative of formula (I) or an agriculturally acceptable salt or metal complex thereof. For this purpose, the 2-benzoylcyclohexane- 1,3 -dione derivatives are normally used in the form of herbicidal compositions (i.e. in association with compatible diluents or carriers and/or surface active agents suitable 5 for use in herbicidal compositions), for example as hereinafter described.

The compounds of formula (I) show herbicidal activity against dicotyledonous (i.e. broad-leafed) and monocotyledonous (i.e. grass) weeds by pre- and/or post-emergence application. 0 By the term "pre-emergence application" is meant application to the soil in which the weed seeds or seedlings are present before emergence of the weeds above the surface of the soil. By the term "post- emergence application" is meant application to the aerial or exposed portions of the weeds which have emerged above the surface of the soil. 25 For example, the compounds of formula (I) may be used to control the growth of: broad-leafed weeds, for example, Abutilon theophrasti. Amaranthus retroflexus, Bidens pilosa. Chenopodium album, Galium aparine, Ipomoea spp. e.g. Ipomoea purpurea. Sesbania exaltata. Sinapis 30 arvensis. Solanum nigrum and Xanthium strumarium, and grass weeds, for example Alopecurus mvosuroides, A vena fatua. Digitaria sanguinalis, Echinochloa crus-galli. Sorghum bicolor, Eleusine indica and Setaria spp, e.g. Setaria faberii or Setaria viridis. and sedges, for example, Cvperus esculentus. 35 The amounts of compounds of formula (I) applied vary with the nature of the weeds, the compositions used, the time of application, the climatic and edaphic conditions and (when used to control the growth of weeds in crop-growing areas) the nature of the crops. When applied to a crop-growing area, the rate of application should be sufficient to control the growth of weeds without causing substantial permanent damage to the crop. In general, taking these factors into account, application rates from 0.01kg to 2kg of active material per hectare give good results. However, it is to be understood that higher or lower application rates may be used, depending upon the particular problem of weed control encountered. The compounds of formula (I) may be used to control selectively the growth of weeds, for example to control the growth of those species hereinbefore mentioned, by pre- or post-emergence application in a directional or non-directional fashion, e.g. by directional or non- directional spraying, to a locus of weed infestation which is an area used, or to be used, for growing crops, for example cereals, e.g. wheat, barley, oats, maize and rice, soya beans, field and dwarf beans, peas, lucerne, cotton, peanuts, flax, onions, carrots, cabbage, oilseed rape, sunflower, sugar beet, and permanent or sown grassland before or after sowing of the crop or before or after emergence of the crop. For the selective control of weeds at a locus of weed infestation which is an area used, or to be used, for growing of crops, e.g. the crops hereinbefore mentioned, application rates from 0.01kg to 1.0kg, and preferably from 0.025kg to 0.25kg, of active material per hectare are particularly suitable. The compounds of formula (I) may also be used to control the growth of weeds, especially those indicated above, by pre- or post- emergence application in established orchards and other tree-growing areas, for example forests, woods and parks, and plantations, e.g. sugar cane, oil palm and rubber plantations. For this purpose they may be applied in a directional or non- directional fashion (e.g. by directional or non-directional spraying) to the weeds or to the soil in which they are expected to appear, before or after planting of the trees or plantations at application rates from 0.25kg to 2.0kg, and preferably from 0.25kg to 1.0kg of active material per hectare. The compounds of formula (I) may also be used to control the growth of weeds, especially those indicated above, at loci which are not crop-growing areas but in which the control of weeds is nevertheless desirable.

Examples of such non-crop-growing areas include airfields, industrial sites, railways, roadside verges, the verges of rivers, irrigation and other waterways, scrublands and fallow or uncultivated land, in particular where it is desired to control the growth of weeds in order to reduce fire risks. When used for such purposes in which a total herbicidal effect is frequently desired, the active compounds are normally applied at dosage rates higher than those used in crop-growing areas as hereinbefore described. The precise dosage will depend upon the nature of the vegetation treated and the effect sought.

Pre- or post-emergence application, and preferably pre-emergence application, in a directional or non-directional fashion (e.g. by directional or non-directional spraying) at application rates from 0.5kg to 2.0kg, and preferably from 0.5kg to 1.0kg, of active material per hectare are particularly suitable for this purpose.

When used to control the growth of weeds by pre-emergence application, the compounds of formula (I) may be incorporated into the soil in which the weeds are expected to emerge. It will be appreciated that when the compounds of formula (I) are used to control the growth of weeds by post-emergence application, i.e. by application to the aerial or exposed portions of emerged weeds, the compounds of formula (I) will also normally come into contact with the soil and may also then exercise a pre-emergence control on later-germinating weeds in the soil. Where especially prolonged weed control is required, the application of the compounds of formula (I) may be repeated if required.

According to a further feature of the present invention, there are provided compositions suitable for herbicidal use comprising one or more of the 2-benzoylcyclohexane- 1,3 -dione derivatives of formula (I) or an agriculturally acceptable salt or metal complex thereof, in association with, and preferably homogeneously dispersed in, one or more compatible agriculturally- acceptable diluents or carriers and/or surface active agents [i.e. diluents or carriers and/or surface active agents of the type generally accepted in the art as being suitable for use in herbicidal compositions and which are compatible with compounds of formula (I)]. The term "homogeneously dispersed" is used to include compositions in which the compounds of formula (I) are dissolved in other components. The term "herbicidal compositions" is used in a broad sense to include not only compositions which are ready for use as herbicides but also concentrates which must be diluted before use. Preferably, the compositions contain from 0.05 to 90% by weight of one or more compounds of formula (I).

The herbicidal compositions may contain both a diluent or carrier and surface-active (e.g. wetting, dispersing, or emulsifying) agent. Surface-active agents which may be present in herbicidal compositions of the present invention may be of the ionic or non-ionic types, for example sulphoricinoleates, quaternary ammonium derivatives, products based on condensates of ethylene oxide with alkyl and polyaryl phenols, e.g. nonyl- or octyl-phenols, or carboxylic acid esters of anhydrosorbitols which have been rendered soluble by etherification of the free hydroxy groups by condensation with ethylene oxide, alkali and alkaline earth metal salts of sulphuric acid esters and sulphonic acids such as dinonyl- and dioctyl-sodium sulphonosuccinates and alkali and alkaline earth metal salts of high molecular weight sulphonic acid derivatives such as sodium and calcium lignosulphonates and sodium and calcium alkylbenzene sulphonates.

Suitably, the herbicidal compositions according to the present invention may comprise up to 10% by weight, e.g. from 0.05% to 10% by weight, of surface-active agent but, if desired, herbicidal compositions according to the present invention may comprise higher proportions of surface-active agent, for example up to 15% by weight in liquid emulsifiable suspension concentrates and up to 25% by weight in liquid water soluble concentrates.

Examples of suitable solid diluents or carriers are aluminium silicate, talc, calcined magnesia, kieselguhr, tricalcium phosphate, powdered cork, absorbent carbon black and clays such as kaolin and bentonite. The solid compositions (which may take the form of dusts, granules or wettable powders) are preferably prepared by grinding the compounds of formula (I) with solid diluents or by impregnating the solid diluents or carriers with solutions of the compounds of formula (I) in volatile solvents, evaporating the solvents and, if necessary, grinding the products so as to obtain powders. Granular formulations may be prepared by absorbing the compounds of formula (I) (dissolved in suitable solvents, which may, if desired, be volatile) onto the solid diluents or carriers in granular form and, if desired, evaporating the solvents, or by granulating compositions in powder form obtained as described above. Solid herbicidal compositions, particularly wettable powders and granules, may contain wetting or dispersing agents (for example of the types described above), which may also, when solid, serve as diluents or carriers.

Liquid compositions according to the invention may take the form of aqueous, organic or aqueous-organic solutions, suspensions and emulsions which may incorporate a surface-active agent. Suitable liquid diluents for incorporation in the liquid compositions include water, glycols, tetrahydrofurfuryl alcohol, acetophenone, cyclohexanone, isophorone, toluene, xylene, mineral, animal and vegetable oils and light aromatic and naphthenic fractions of petroleum (and mixtures of these diluents). Surface-active agents, which may be present in the liquid compositions, may be ionic or non-ionic (for example of the types described above) and may, when liquid, also serve as diluents or carriers. Powders, dispersible granules and liquid compositions in the form of concentrates may be diluted with water or other suitable diluents, for example mineral or vegetable oils, particularly in the case of liquid concentrates in which the diluent or carrier is an oil, to give compositions ready for use. Liquid concentrates in which the diluent or carrier is an oil may be used without further dilution using the electrostatic spray technique.

Herbicidal compositions according to the present invention may also contain, if desired, conventional adjuvants such as adhesives, protective colloids, thickeners, penetrating agents, spreading agents, stabilisers, sequestering agents, anti-caking agents, colouring agents and corrosion inhibitors. These adjuvants may also serve as carriers or diluents.

Herbicidal compositions according to the present invention may also comprise the compounds of formula I in association with, and preferably homogeneously dispersed in, one or more other pesticidally active compounds and, if desired, one or more compatible pesticidally acceptable diluents or carriers, surface-active agents and conventional adjuvants as hereinbefore described.

Examples of other pesticidally active compounds which may be included in, or used in conjunction with, the herbicidal compositions of the present invention include herbicides, for example to increase the range of weed species controlled for example alachlor [2-chloro-2,6'- diethyl-N-(methoxy-methyl)-acetanilide], atrazine [2-chloro-4- ethylamino-6-isopropylamino-l,3,5-triazine], bromoxynil [3,5-dibromo- 4-hydroxybenzonitrile], chlortoluron [N'-(3-chloro-4-methylphenyl)- N,N-dimethy lurea] , cy anazine [2-chloro-4-( 1 -cyano- 1 - methylethylamino)-6-ethylamino-l,3,5-triazine], 2,4-D [2,4- dichlorophenoxy-acetic acid], dicamba [3,6-dichloro-2-methoxybenzoic acid], difenzoquat [1,2- dimethyl-3,5-diphenyl-pyrazolium salts], flampropmethyl [methyl N-2-(N- benzoyl-3-chloro-4-fluoroanilino)- propionate], fluometuron [N'-(3-trifluoro- methylphenyl)-N,N- dimethylurea], isoproturon [N'-(4-isopropylphenyl)-N,N-dimethylurea], insecticides, e.g. synthetic pyrethroids, e.g permethrin and cypermethrin, and fungicides, e.g. carbamates, e.g. methyl N-(l-butyl-carbamoyl- benzimidazol-2-yl)carbamate, and triazoles e.g. 1 -(4-chloro-phenoxy)- 3 ,3-dimethyl- 1 -( 1 ,2,4-triazol- 1 -y l)-butan-2-one.

Pesticidally active compounds and other biologically active materials which may be included in, or used in conjunction with, the herbicidal compositions of the present invention, for example those hereinbefore mentioned, and which are acids, may, if desired, be utilised in the form of conventional derivatives, for example alkali metal and amine salts and esters.

The following Examples illustrate herbicidal compositions according to the present invention. The following trade marks appear in the Examples: Synperonic, Solvesso, Arylan, Arkopon, Sopropon, Tixosil, Soprophor, Attagel, Rhodorsil.

Example Cl:

An emulsifiable concentrate is formed from: Active ingredient (Compound 1) 20% w/v N-Methylpyrrolidinone (NMP) 25% w/v

Calcium dodecylbenzenesulphonate (70%) (CaDDBS) (Arylan CA) 4% w/v

Nonylphenol ethylene oxide propylene oxide condensate (NPEOPO) (Synperonic NPE 1800) 6% w/v Aromatic solvent (Solvesso) to 100 volumes by stirring NMP, active ingredient (Compound 1), CaDDBS,

NPEOPO and Aromatic solvent until a clear solution is formed, and adjusting to volume with Aromatic solvent.

Example C2 A wettable powder is formed from:

Active ingredient (Compound 1) 50% w/w

Sodium dodecylbenzenesulphonate (Arylan SX85) 3% w/w

Sodium methyl oleoyl taurate (Arkopon T) 5% w/w

Sodium polycarboxylate (Sopropon T36) 1 % w/w Microfine silicon dioxide (Tixosil 38) 3% w/w

China clay 38% w/w by blending the above ingredients together and grinding the mixture in an air jet mill.

Example C3

A suspension concentrate is formed from:

Active ingredient (Compound 1) 50% w/v Antifreeze (Propylene glycol) 5% w/v

Ethoxylated tristyrylphenol phosphate (Soprophor FL) 0.5% w/v

Nonyl phenol 9 mole ethoxylate (Ethylan BCP) 0.5% w/v Sodium polycarboxylate (Sopropon T36) 0.2% w/v

Attaclay (Attagel) 1.5% w/v

Antifoam (Rhodorsil AF426R) 0.003% w/v

Water to 100 volumes by stirring the above ingredients together and milling in a bead mill. Example C4

A water dispersible granule is formed from: Active ingredient (Compound 1) 50% w/w

Sodium dodecylbenzenesulphonate (Arylan SX 85) 3% w/w

Sodium methyl oleoyl taurate (Arkopon T) 5% w/w

Sodium polycarboxylate (Sopropon T36) 1% w/w

Binder (Sodium lignosulphonate) 8% w/w

China clay 30% w/w Microfine silicon dioxide (Tixosil 38) 3% w/w by blending the above ingredients together, grinding the mixture in an air jet mill and granulating by addition of water in a suitable granulation plant (e.g. Fluid bed drier) and drying. Optionally the active ingredient may be ground either on its own or admixed with some or all of the other ingredients.

The compounds of the invention have been used in herbicidal applications according to the following procedures.

METHOD OF USE OF HERBICIDAL COMPOUNDS: TEST METHOD A a) General

Appropriate quantities of the compounds used to treat the plants were dissolved in acetone to give solutions equivalent to application rates of up to 250g test compound per hectare (g/ha). These solutions were applied from a standard laboratory herbicide sprayer delivering the equivalent of 290 litres of spray fluid per hectare. b) Weed control : Pre-emergence

The seeds were sown in 70 mm square, 75 mm deep plastic pots in non-sterile soil . The quantities of seed per pot were as follows:-

Weed species Approx number of seeds/pot

1 Broad-leafed weeds

Abutilon theophrasti 10

Amaranthus retroflexus 20

Galium aparine 10

Ipomoea purpurea 10

Xanthium strumarium 2

2) Grass weeds

Alopecurus myosuroides 15

Avena fatua 10

Echinochloa crus-galli 15

Setaria viridis 20

3) Sedges

Cyperus esculentus 3

Crop

1) Broad-leafed

Cotton 3

Soya 3

2) Grass

Maize 2

Rice 6

Wheat 6 The compounds of the invention were applied to the soil surface, containing the seeds, as described in (a). A single pot of each crop and each weed was allocated to each treatment, with unsprayed controls and controls sprayed with acetone alone.

After treatment the pots were placed on capillary matting kept in a glass house, and watered overhead . Visual assessment of crop damage was made 20-24 days after spraying. The results were expressed as the percentage reduction in growth or damage to the crop or weeds, in comparison with the plants in the control pots. c Weed control : Post-emergence

The weeds and crops were sown directly into John Innes potting compost in 75 mm deep, 70 mm square pots except for Amaranthus which was pricked out at the seedling stage and transferred to the pots one week before spraying. The plants were then grown in the greenhouse until ready for spraying with the compounds used to treat the plants. The number of plants per pot were as follows :- \) Broad leafed weeds

Weed species Number of plants per pot Growth stage

Abutilon theophrasti 3 1-2 leaves

Amaranthus retroflexus 4 1 -2 leaves

Galium aparine 3 1 ^st whorl

Ipomoea purpurea 3 1 -2 leaves

Xanthium strumarium 1 2-3 leaves

2) Grass weeds Weed species Number of plants per pot Growth stage

Alopecurus myosuroides 8-12 1-2 leaves Avena fatua 12-18 1 -2 leaves Echinochloa crus-galli 4 2-3 leaves

Setaria viridis 15-25 1-2 leaves.

3) Sedges Weed species Number of plants per pot Growth stage

Cyperus esculentus 3 3 leaves.

H Broad leafed Crops Number of plants per pot Growth stage

Cotton 2 l leaf

Soya 2 2 leaves.

2) Grass

Crops Number of plants per pot Growth stage

Maize 2 2-3 leaves

Rice 4 2-3 leaves

Wheat 5 2-3 leaves.

The compounds used to treat the plants were applied to the plants as described in (a). A single pot of each crop and weed species was allocated to each treatment, with unsprayed controls and controls sprayed with acetone alone.

After treatment the pots were placed on capillary matting in a glass house, and watered overhead once after 24 hours and then by controlled sub-irrigation. Visual assessment of crop damage and weed control was made 20-24 days after spraying. The results were expressed as the percentage reduction in growth or damage to the crop or weeds, in comparison with the plants in the control pots.

TEST METHOD B

Paddy post-emergence application in greenhouse

Paddy field soil was filled in 170 cm² plastic pots, a suitable amount of water and chemical fertilisers were added thereto and kneaded to convert it to a state of a paddy.

Paddy rice plants (variety; Koshihikari), that had been grown in advance in a greenhouse to a stage of two leaves, were transplanted to each pot (two seedlings per pot). Then in each pot there were sown predetermined amounts of seeds of Echinochloa orvzicola. Monochoria vaginalis, Lindernia procumbens and Scirpus juncoides respectively, and water was added to a depth of 3 cm.

After having grown the plants in a greenhouse until Echinochloa orvzicola reached a stage of 1.5 leaves, solutions were prepared in 100% acetone using compounds described in the Examples so that they contained active ingredients in an amount equivalent to 75, 300 and 1200 g/ha. The solutions were applied by dropping with a pipette. After 21 days from the application with the chemicals, herbicidal effects on each weed and phytotoxicity on paddy rice plants were visually assessed, and the results expressed as the percentage reduction in growth or damage to the crop or weeds in comparison with the plants in the control pots.

When applied pre- or post-emergence in Test Method A at 250g/ha or less compounds 1, 3, 32, 42, 99 and 166 of the invention gave at least 90% reduction in growth of one or more of the weed species; at levels of application toxic to the weeds this compound was selective in at least one of the crop species.

When applied at 1200 g/ha or less, in Test Method B, compounds 1-3, 31, 88, 99 and 166 of the invention gave at least 90% reduction in growth of one or more of the weed species listed above.

Claims

1. A 2-benzoylcyclohexane- 1 ,3 -dione derivative of formula

(I):

(I) wherein:

R¹ represents a group of formula (II), (III), (IV) or (V):

(IV) (V) or a corresponding formula (IVa) or (Va):

(IVa) (Va) in which the position of the carbonyl group and the group Q are reversed and the double bond in the ring is attached to the carbon atom attached to the group Q; R² represents :- halogen; lower alkyl which is substituted by one or more groups -OR¹⁰; a cycloalkyl group containing from three to six carbon atoms; or a group selected from nitro, cyano, -CO₂R¹⁰, -NR^R^{1 1}, -S(O)_pR¹²,

-O(CH₂)_mOR¹⁰, -COR¹⁰, -N(R¹³)SO₂R¹², -OR¹², -OH, -OSO₂R¹², -(CR¹⁴R¹⁵)_tS(O)_qR¹², -CONR^R¹ !, -N(R¹³)-C(Z)=Y,

-C(R¹⁴R¹⁵)NR¹³R¹⁶, -CH₂P(O)R¹⁰ R^10b, R¹⁷, SF₅ and benzyl optionally substituted by from one to five groups R¹ which may be the same or different; or two groups R², together with adjacent carbon atoms of the phenyl ring form a second phenyl ring or a 5- or 6-membered saturated or unsaturated heterocyclic ring which is fused to the first ring and contains one or two oxygen or sulphur atoms and is optionally substituted by one or more halogen , lower alkyl, lower haloalkyl or lower alkoxy groups, or one of the ring carbon atoms of the heterocyclic ring forms part of a carbonyl group or an oxime or lower alkoxyimine derivative thereof; (examples of the optionally substituted fused ring systems when formed include thiochroman, chroman, 2H-thiochromene, 2H-chromene, 4H-thiochromene, 4H-chromene, iso hiochroman, isochroman, isothiochromene, isochromene, 1,3-benzodithiole, 1,3- benzodioxole, 1,3-benzoxathiole, 1 ,4-benzodithiin, 1 ,4-benzoxathiin,

1 ,4-benzoxathian, 1,3-benzoxathian, 3,1-benzoxathian and 1,3- benzodithian); n represents zero or an integer from one to three; where n is greater than one the groups R² may be the same or different; m represents one, two or three; p and q represent zero, one or two; t represents one, two, three or four (preferably one); when t is more than one R¹⁴ and R¹ * may be the same or different; X represents -(CR¹⁴R¹⁵)_V-; v represents zero or one;

R³ represents a 5-membered heteroaromatic ring of formula (VI)

ΓÇö _N

(VI) in which D, E, G and J independently represent CR¹ or a nitrogen atom, with at least one of D, E, G and J representing CR¹⁹ (when more than one CR¹⁹ group is present they may be the same or different); or two adjacent groups may form a phenyl or a 5- to 7- membered heteroaromatic ring which is fused to the first ring and is optionally substituted by one or more groups R²⁰, and when present the 5- to 7- membered heterocyclic ring may contain from one to four heteroatoms in the ring which may be the same or different selected from nitrogen, oxygen and sulphur; z represents one or two; when z represents two the -XR³ groups may be the same or different;

Q represents hydroxy, lower alkoxy, OR²¹, SR²¹ or SR²²;

L represents oxygen or NR¹⁴; R⁴, R^4a, R^4b, R⁵, R^5a, R^5b, R⁶, R^6a, R6^b, R⁷, R^7a R^7b, R⁸,

R ^a, R⁸ , R⁹, R ^a and R ^b represent the same or different groups selected from hydrogen, R¹⁷, -(CH₂)_uCO₂R¹⁴, halogen, cyano, lower alkoxy, -(CH₂)_x-[phenyl optionally substituted by from one to five groups R¹⁸ which may be the same or different], and cycloalkyl containing from three to six carbon atoms optionally substituted by lower alkyl or -S(O)_pR²² ; u represents zero, one or two; x represents zero or one;

R¹⁰ and R^{1 1} which may be the same or different, each represents hydrogen or R 1⁷ ; 10a nd RlOb ich may be the same or different, each represents lower alkyl or lower alkoxy;

R¹² represents :-

R¹⁷; or a cycloalkyl group containing from three to six carbon atoms; or a group -(CH₂)_w-[phenyl optionally substituted by from one to five groups R¹⁸ which may be the same or different]; w represents zero or one; R¹³ represents :- hydrogen, R¹² or OR²²; R¹⁴ and R¹^ independently represent hydrogen, lower alkyl or lower haloalkyl (preferably containing up to three carbon atoms); R¹⁶ represents -SO₂R¹² or -C(Z)=Y;

R¹⁷ represents :- lower alkyl, lower haloalkyl, lower alkenyl, lower haloalkenyl, lower alkynyl or lower haloalkynyl;

R¹⁸ represents a group selected from halogen, R²³, nitro, cyano, -CO₂R¹⁰, -S(O)_pR²², -OR²² and -NR¹⁰R 1;

R¹⁹ represents :- a group selected from hydrogen, halogen, R²³, nitro, cyano,

-CO₂R¹⁰, -S(O)_pR²², -OR²², -NR¹⁰R^╧Ç and cyclopropyl;

R²⁰ represents halogen or R¹⁷;

R²¹ represents phenyl optionally substituted by from one to five groups selected from halogen, lower alkyl, lower haloalkyl, lower alkoxy and nitro;

R²² represents lower alkyl or lower haloalkyl;

R²³ represents a straight- or branched- chain alkyl group containing one to three carbon atoms optionally substituted by one or more halogen atoms; Y is oxygen or sulphur (preferably Y represents oxygen);

Z represents a group selected from R¹⁷, -NR²⁴R²^, -SR¹² and -OR¹²; and

R²⁴ and R²* independently represent hydrogen or R¹ ; or an agriculturally acceptable salt or metal complex thereof.

2. A compound according to claim 1 in which one

XR³ group is present.

3. A compound according to claim 1 or 2 in which X represents -(CR¹⁴R¹^)_V- and v represents zero.

4. A compound according to any one of the preceding claims in which Q represents hydroxy.

5. A compound according to any one of the preceding claims in which R³ is selected from pyrazol-1-yl, imidazol-1-yl,

1,2,4-triazol-l-yl, 1,2,3-triazol-l-yl, l,2,3-triazol-2-yl, 1,2,3,4-tetrazol-l-yl and benzimidazol-1-yl.

6. A compound according to any one of the preceding claims in which R¹ represents a group of formula (II).

7. A compound according to any one of the preceding claims in which R² represents halogen, a straight- or branched- chain alkyl group containing up to four carbon atoms optionally substituted by one or more halogen atoms; or a group selected from nitro, cyano, -S(O)_pR¹², -OR¹², -CH S(O)_qR¹² wherein R¹² represents lower alkyl or lower haloalkyl; or benzyl optionally substituted by -S(O)_pR²² wherein R²² represents lower alkyl; or two groups R² together with adjacent carbon atoms of the phenyl ring form a second phenyl ring.

8. A compound according to any one of the preceding claims in which R¹ is selected from: a group of formula (II) wherein R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ represent hydrogen or lower alkyl; or a group of formula (III) wherein R^4b, R^5b, R^6b, R^7b, R^8b and

R ^b represent hydrogen or lower alkyl; or a group of formula (IV) wherein R^8a and R^9a represent hydrogen or lower alkyl; and a group of formula (V) wherein R^4a, R^^a, R*>^a and R^7a represent hydrogen or lower alkyl, and L represents NH;

Q represents hydroxy or -S-phenyl;

R² represents :- a straight- or branched- chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms; or a group selected from halogen, nitro, -S(O)_pR¹², -OR¹²,

-CH₂S(O)_qR¹², -CH2NR¹3R16_J -N(R¹³)SO₂R¹², -N(R¹³)CO₂R¹² and benzyl optionally substituted by -S(O)pR²²; n represents zero, one or two; X represents -(CH₂)_V-; R³ represents a 5-membered heteroaromatic ring of formula (VI) which is selected from pyrazol-1-yl, imidazol-1-yl, 1,2,4-triazol-l-yl, 1,2,3-triazol-l-yl, l,2,3-triazol-2-yl, 1,2,3,4-tetrazol-l-yl and benzimidazol-1-yl, the ring systems of which are substituted by one or two R¹⁹ groups; z represents one; R¹² and R¹³ independently represent lower alkyl or lower haloalkyl;

R¹⁶ represents -SO₂R¹² or CO₂R¹²;

R¹⁹ represents hydrogen or a straight- or branched- chain alkyl group containing up to three carbon atoms; and

R²² represents lower alkyl.

9. A compound according to any one of the preceding claims in which R¹ represents a group of formula (II) wherein R⁴, R^,

R6, R⁷, R⁸ and R⁹ represent hydrogen, methyl or ethyl; Q represents hydroxy or -S-phenyl;

R² represents :- halogen, a straight- or branched- chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms; or a group selected from -S(O)_pCH3, -CH₂S(O)_qCH3, -OCH3 and benzyl optionally substituted by -S(O)_pCH3;

X represents a bond;

R³ represents a pyrazol-1-yl, imidazol-1-yl, 1,2,3-triazol-l-yl, l,2,3-triazol-2-yl, 1,2,4-triazol-l-yl or 1,2,3,4-tetrazol-l-yl ring substituted by one or two R¹⁹ groups, wherein R¹ represents hydrogen, halogen or optionally halogenated methyl; z represents one; and n represents 0, 1 or 2.

10. A herbicidal composition comprising an effective amount of a 2-benzoylcyclohexane- 1,3 -dione derivative according to any one of claims 1 to 9 or an agriculturally acceptable salt or metal complex thereof, in association with an agriculturally acceptable diluent or carrier and/or surface active agent.

11. A method for the control of weeds at a locus which comprises applying to said locus an effective amount of a 2- benzoylcyclohexane- 1,3 -dione derivative according to any one of claims

1 to 9 or an agriculturally acceptable salt or metal complex thereof or a herbicidal composition according to claim 10.

12. A method according to claim 1 1 wherein the locus is an area used, or to be used, for the growing of crops and the 2- benzoylcyclohexane- 1,3 -dione derivative or salt or metal complex thereof is applied at an application rate of from 0.01kg to 1 kg/ha.

13. A process for the preparation of a 2- benzoylcyclohexane- 1,3 -dione derivative of formula (I) as defined in claim 1 which comprises the rearrangement of a compound of formula (VII), (VIII), (IX) or (X):

(VII) (VIII)

(IX) (X) or of an isomeric ester in which the position of the ring carbonyl and ester groups of formula (IX) or (X) is reversed; and wherein the various symbols are as defined in claim 1, with a source of cyanide in the presence of a base.

14. A compound of formula (VII), (VIII), (IX) and (X):

(IX) (X) or an isomeric ester in which the position of the ring carbonyl and ester groups of formula (IX) or (X) is reversed; and wherein the various symbols are as defined in claim 1.