4-benzoyl isoxazoles derivatives and their use as herbicides

Abstract

4-Benzoylisoxazole derivatives of formula (I), wherein R represents hydrogen or ester; R 1 represents alkyl, haloalkyl or optionally substituted cycloalkyl; R 2 represents halogen, optionally halogenated alkyl, alkenyl or alkynyl; alkyl substituted by one or more groups —OR 5 ; nitro, cyano, —CO 2 R 5 , —S(O) p R 6 , —O(CH 2 ) m OR 5 , —COR 5 , —NR 5 R 6 , —N(R 8 )SO q R 7 , —CONR 9 R 10 or —OR 51 ; optionally substituted phenyl; R 3 represents —S(O) q R 7 ; X represents —N(R 8 )—; n represents zero or an integer from one to four; R 5 , R 51 and R 6 independently represent hydrogen, optionally halogenated alkyl, alkenyl or alkynyl; optionally substituted phenyl; or cycloalkyl; R 7 represents alkyl, alkenyl or alkynyl optionally substituted by halogens; cycloalkyl; optionally substituted phenyl; or amino; R 8 represents hydrogen; alkyl, alkenyl or alkynyl optionally substituted by halogens; cycloalkyl; optionally substituted phenyl; or alkoxy; m is 1, 2 or 3; p is 0, 1 or 2; and q is zero or two; and their used as herbicides is described.

1 . A 4-benzoylisoxazole derivative of formula (I):  
       
         
           
           
               
               
           
         
         wherein:  
         R represents the hydrogen atom or a group —CO 2 R 4 ;  
         R 1  represents:— 
         a straight- or branched-chain alkyl group containing up to six carbon atoms which is optionally substituted by one or more halogen atoms; or  
         a cycloalkyl group containing from three to six carbon atoms optionally substituted by one or more R 5  groups or one or more halogen atoms;  
         R 2  represents:— 
         a halogen atom;  
         a straight- or branched-chain alkyl alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
         a straight- or branched-chain alkyl group containing up to six carbon atoms which is substituted by one or more groups —OR 5 ;  
         a group selected from nitro, cyano, —CO 2 R 5 , —S(O) p R 6 , —O(CH 2 ) m OR 5 , —COR 5 , —NR 5 R 6 , -N(R 8 )SO q R 7 , —CONR 9 R 10  and —OR 51 ;  
         phenyl optionally substituted by from one to three groups R 21  which may be the same or different;  
         R 3  represents —S(O) q R 7 ;  
         X represents a group —N(R 8 )—;  
         n represents zero or an integer from one to four; where n is greater than one the groups R 2  may be the same or different;  
         R 4  represents a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
         R 5 , R 51  and R 6 , which may be the same or different, each represents:— 
         the hydrogen atom;  
         a straight- or branched-chain allyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
         phenyl optionally substituted by from one to five groups R 2  which may be the same or different; or  
         a cycloalkyl group containing from three to six carbon atoms;  
         R 7  represents:— 
         a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
         a cycloalkyl group containing from three to six carbon atoms;  
         phenyl or benzyl optionally substituted by from one to five groups R 21  which may be the same or different;  
         or —NR 9 R 10 ;  
         R 8  represents:  
         the hydrogen atom; or  
         a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to ten carbon atoms optionally substituted by one or more halogen atoms;  
         a cycloalkyl group containing from three to six carbon atoms;  
         phenyl optionally substituted by from one to five groups which may be the same or different selected from halogen, nitro, cyano, R 5 , S(O) p R 5  and —OR 5 ; or  
         a group —OR 11 ;  
         R 9  represents:— 
         the hydrogen atom;  
         a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
         or phenyl optionally substituted by from one to five groups R 2  which may be the same or different;  
         R 10  represents a group selected from R 5  and —OR 11 ;  
         or R 9  and R 10 , together with the nitrogen to which they are attached, may form a 5 or 6 membered ring optionally containing an oxygen or nitrogen atom in the ring, wherein the ring is optionally substituted by one or more alkyl groups containing up to 3 carbon atoms;  
         R 11  represents a straight- or branched-chain alkyl group containing up to six carbon atoms;  
         R 21  represents:— 
         a halogen atom;  
         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 nitro, cyano, —S(O) p R 5  and —OR 5 ;  
         m represents one, two or three;  
         p represents zero, one or two; and  
         q represents zero or two;  
         or an agriculturally acceptable salt thereof  
       
     
     
         2 . A compound according to  claim 1  wherein: 
 R represents the hydrogen atom or a group —CO 2 R 4 ;  
 R 1  represents:— 
 a straight- or branched-chain alkyl group containing up to six carbon atoms which is optionally substituted by one or more halogen atoms; or  
 a cycloalkyl group containing from three to six carbon atoms optionally substituted by one or more R 5  groups;  
 R 2  represents:— 
 a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 a straight- or branched-chain alkyl group containing up to six carbon atoms which is substituted by a group —OR 5 ;  
 a halogen atom;  
 phenyl optionally substituted by from one to three groups R 21  which may be the same or different;  
 a group selected from —COR 5 , nitro, cyano, —CO 2 R 5 ; —S(O) p R 6 , —O(CH 2 ) m OR 5 , —N(R 8 )SO 2 R 7 , —CONR 9 R 10  and —OR 51 ;  
 R 3  represents —S(O) q R 7 ;  
 X represents a group —N(R 8 )—;  
 n represents zero or an integer from one to four; where n is greater than one the groups R 2  may be the same or different;  
 R 4  represents a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 R 5  represents:— 
 a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms; or  
 a cycloalkyl group containing from three to six carbon atoms;  
 R 51  represents:— 
 a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 a cycloalkyl group containing from three to six carbon atoms;  
 or phenyl optionally substituted by from one to five groups which may be the same or different elected from a halogen atom, a straight- or branched-chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms; nitro, cyano, —S(O) p R 5  and —OR 5 ;  
 R 6  represents:— 
 a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 a cycloalkyl group containing from three to six carbon atoms;  
 or phenyl optionally substituted by from one to five groups which may be the same or different selected from a halogen atom, a straight- or branched-chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms; nitro, cyano, —S(O) p R 5  and —OR 5 ;  
 R 7  represents:— 
 a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 a cycloalkyl group containing from three to six carbon atoms;  
 phenyl optionally substituted by from one to five groups R 21  which may be the same or different;  
 or —NR 9 R 10 ;  
 R 8  represents:  
 the hydrogen atom; or  
 a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 a cycloalkyl group containing from three to six carbon atoms;  
 phenyl optionally substituted by from one to five groups which may be the same or different selected from a halogen atom, a straight- or branched-chain alkyl group containing up to three carbon atoms optionally substituted by one or more halogen atoms; nitro, cyano, —S(O) p R 5  and —OR 5 ;  
 or a group —OR 11 ;  
 R 9  represents hydrogen or a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 R 10  represents a group selected from R 5  and —OR 11 ;  
 or R 9  and R 10 , together with the nitrogen to which they are attached, may form a 5 or 6 membered ring optionally containing an oxygen or nitrogen atom in the ring, wherein the ring is optionally substituted by one or more alkyl groups containing up to 3 carbon atoms;  
 R 11  represents a straight- or branched-chain alkyl group containing up to six carbon atoms;  
 R 21  represents:— 
 a halogen atom;  
 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 nitro, cyano, —S(O) p R 5  and —OR 5 ;  
 m represents one, two or three;  
 p represents zero, one or two; and  
 q represents two.  
 
     
     
         3 . A compound according to  claim 1  wherein: 
 R represents the hydrogen atom or a group —CO 2 R 4 ;  
 R 1  represents:— 
 a straight- or branched-chain alkyl group containing up to six carbon atoms which is optionally substituted by one or more halogen atoms; or  
 a cycloalkyl group containing from three to six carbon atoms optionally substituted by one or more R 5  groups or one or more halogen atoms;  
 R 2  represents:— 
 a halogen atom;  
 a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 a straight- or branched-chain alkyl group containing up to six carbon atoms which is substituted by one or more groups —OR 5 ;  
 a group selected from nitro, cyano, —CO 2 R 5 , —S(O) p R 6 , —O(CH 2 ) m OR 5 , —COR 5 , —NR 5 R 6 , —N(R 8 )SO q R 7  and —OR 51 ;  
 R 3  represents —S(O)R 7 ;  
 X represents a group —N(R 8 )— 
 n represents zero or an integer from one to four; where n is greater than one the groups R 2  may be the same or different;  
 R 4  represents a straight- or branched-chain alkyl group containing up to six carbon atoms which is optionally substituted by one or more halogen atoms;  
 R 5 , R 51  and R 6 , which may be the same or different, each represents:  
 the hydrogen atom;  
 a straight- or branched-chain alkyl group containing up to six carbon atoms which is optionally substituted by one or more halogen atoms;  
 phenyl optionally substituted by from one to five groups R 2  which may be the same or different;  
 R 7  represents:  
 a straight- or branched-chain alkyl group containing up to six carbon atoms which is optionally substituted by one or more halogen atoms:  
 phenyl optionally substituted by from one to five groups R 21  which may be the same or different; or  
 a group —NR 9 R 10 ;  
 R 8  represents:  
 the hydrogen atom;  
 a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to ten carbon atoms which is optionally substituted by one or more halogen atoms; or  
 phenyl optionally substituted from one to five groups which may be the same or different selected from nitro, halogen, R 5  and —OR 5 ;  
 R 9  and R 10 , which may be the same or different, each represents:— 
 the hydrogen atom;  
 a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 or phenyl optionally substituted by from one to five groups R 2  which may be the same or different;  
 R 21  represents:— 
 a halogen atom;  
 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 nitro, cyano, —S(O) p R 6  and —OR 5 ;  
 p represents zero, 1 or 2;  
 q represents zero or 2; and  
 m represents 1, 2 or 3.  
 
     
     
         4 . A compound according to  claim 1 ,  2  or  3  wherein the 5- and 6- positions of the benzoyl ring are unsubstituted.  
     
     
         5 . A compound according to any one of the preceding claims wherein the 2-position of the benzoyl ring is substituted.  
     
     
         6 . A compound according to any one of claims  1 ,  2 ,  4  and  5  wherein: 
 R 1  represents:— 
 a straight- or branched-chain alkyl group containing up to six carbon atoms which is optionally substituted by one or more halogen atoms; or  
 a cycloalkyl group containing from three to six carbon atoms optionally substituted by one or more methyl groups;  
 R 2  represents:— 
 a halogen atom;  
 a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 a straight- or branched-chain alkyl group containing up to six carbon atoms which is substituted by a group —OR 5 ;  
 phenyl optionally substituted by from one to three groups R 21  which may be the same or different;  
 or a group selected from —COR 5 , cyano, nitro, —CO 2 R 5 , —S(O) p R 6 , —O(CH 2 ) m OR 5 , —N(R 8 )SO 2 R 7  and —OR 51 ;  
 n represents zero or an integer from one to three; where n is greater than one the groups R 2  may be the same or different;  
 R 5  represents:— 
 a straight- or branched-chain alkyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 or a cycloalkyl group containing from three to six carbon atoms;  
 R 51  and R 6 , which may be the same or different, each represents:— 
 a straight- or branched-chain alkyl or alkenyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 a straight- or branched-chain alkynyl group containing from three to six carbon atoms;  
 a cycloalkyl group containing three to six carbon atoms;  
 R 7  represents:— 
 a straight- or branched-chain alkyl or alkenyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 a straight- or branched-chain alkynyl group containing from three to six carbon atoms;  
 a cycloalkyl group containing three to six carbon atoms; or  
 phenyl optionally substituted by from one to three groups R 21  which may be the same or different;  
 R 8  represents:— 
 the hydrogen atom; or  
 a straight- or branched-chain alkyl or alkenyl group containing up to six carbon atoms optionally substituted by one or more halogen atoms;  
 a straight- or branched-chain alkynyl group containing from three to six carbon atoms;  
 or a cycloalkyl group containing three to six carbon atoms;  
 R 21  represents:— 
 a halogen atom;  
 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 nitro, cyano, —S(O) p R 5  and —OR 5 ;  
 q represents two;  
 m represents two or three; and  
 p represents zero, one or two.  
 
     
     
         7 . A compound according to-any one of claims  1 ,  2  and  4  to  6  wherein: 
 R 1  represents:— 
 a straight- or branched-chain alkyl group containing up to three carbon atoms; or  
 a cycloalkyl group containing three or four carbon atoms optionally substituted by a methyl group;  
 R 2  represents:— 
 a chlorine, bromine or fluorine atom; or  
 a straight- or branched-chain alkyl, alkenyl or alkynyl group containing up to four carbon atoms optionally substituted by one or more halogen atoms;  
 a straight- or branched-chain alkyl group containing up to four carbon atoms which is substituted by a group —OR 5 ; or  
 a group selected from —COR 5 , —CO 2 R 5 , —S(O) p R 6 , —O(CH 2 ) m OR 5 , —N(R 8 )SO 2 R 7  and —OR 51 ;  
 R 5  and R 6 , which may be the same or different, each represents:— 
 a straight- or branched-chain alkyl group containing up to four carbon atoms optionally substituted by one or more chlorine, bromine or fluorine atoms; or  
 a cyclopropyl group;  
 R 51  and R 7 , which may be the same or different, each represents:— 
 a straight- or branched-chain alkyl or alkenyl group containing up to four carbon atoms optionally substituted by one or more chlorine, bromine or fluorine atoms;  
 a straight- or branched-chain alkynyl group containing three or four carbon atoms; or  
 a cyclopropyl group;  
 R 8  represents:— 
 the hydrogen atom;  
 a straight- or branched-chain alkyl or alkenyl group containing up to four carbon atoms optionally substituted by one or more chlorine, bromine or fluorine atoms;  
 a straight- or branched-chain alkynyl group containing three or four carbon atoms; or  
 a cyclopropyl group;  
 q represents two;  
 m represents two or three; and  
 p represents zero, one or two.  
 
     
     
         8 . A compound according to any one of claims  1 ,  2  and  4  to  7  wherein: 
 R 1  represents methyl, ethyl, isopropyl, cyclopropyl or 1-methylcyclopropyl;  
 R 2  represents:— 
 a bromine, chlorine or fluorine atom; or  
 a straight- or branched-chain allyl or alkenyl group containing up to four carbon atoms optionally substituted by one or more chlorine, bromine or fluorine atoms;  
 a group selected from —COR 5 , —CO 2 R 5 , —SR 6 , —O(CH 2 ) m OR 5 , —OR 51  and —N(R 8 )SO 2 R 7 ; or  
 a straight- or branched chain alkyl group containing up to four carbon atoms which is substituted by —OR 5 ;  
 R 5  and R 6 , which may be the same or different, each represents a straight- or branched-chain alkyl group containing up to three carbon atoms;  
 R 51  represents:— 
 a straight- or branched-chain alkyl group containing up to four carbon atoms optionally substituted by one or more chlorine, bromine or fluorine atoms;  
 a straight- or branched-chain alkenyl or alkynyl group containing three or four carbon atoms; or  
 a cyclopropyl group;  
 R 7  represents:— 
 a straight- or branched-chain allyl group containing up to three carbon atoms optionally substituted by one or more chlorine, bromine, or fluorine atoms; or I  
 an allyl group optionally substituted by one or more chlorine, fluorine or bromine atoms;  
 R 8  represents:— 
 the hydrogen atom;  
 a straight- or branched-chain alkyl group containing up to three carbon atoms optionally substituted by one or more chlorine, bromine, or fluorine atoms; or  
 an allyl group optionally substituted by one or more chlorine, fluorine or bromine atoms;  
 q represents two; and  
 m represents two or three.  
 
     
     
         9 . A compound according to  claim 1  wherein 
 R represents hydrogen or —CO 2 Et;  
 R 1  represents cyclopropyl;  
 R 2  represents a halogen atom or a group selected from nitro, trifluoromethyl, methyl, trifluoromethoxy, —S(O) p Me and —N(R 8 )SO 2 R 7 ;  
 R 7  represents a straight- or branched-chain allyl group containing up to three carbon atoms, phenyl or benzyl;  
 R 8  represents a straight- or branched-chain alkyl group containing up to four carbon atoms, methoxy or phenyl;  
 p is zero, one or two;  
 n represents zero, one or two; and  
 q represents two.  
 
     
     
         10 . A compound according to any one of the preceding claims wherein a group —XR3 is in the 2- or 4- position of the benzoyl ring.  
     
     
         11 . A compound according to any one of the preceding claims wherein: 
 R 1  represents cyclopropyl;    R 2  represents a halogen atom;    R 7  represents methyl;    R 8  represents hydrogen or methyl; and    n represents zero or one.    
     
     
         12 . The compound according to  claim 1  which is: 
 4-[2-chloro-4-(methylsulphonyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 4-[4-chloro-2-(N-methyl-N-methylphonyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 5-cyclopropyl-4-[2-(N-methyl-N-methylsulphonyl)amino-benzoyl]isoxazole;  
 4-[4-chloro-2-(N-ethyl-N-methylsulphonyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 5-cyclopropyl-4-[2-(N-methyl-N-methylsulphonyl)amino-4-nitro-benzoyl]isoxazole;  
 5-cyclopropyl-4-[4-(N-methyl-N-methylsulphonyl)amino-2-nitro-benzoyl]isoxazole;  
 5-cyclopropyl-4-[4-methyl-2-(N-methyl-N-methylsulphonyl)amino-benzoyl]isoxazole;  
 4-[4-chloro-2-(N-n-propyl-N-methylsulphonyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 5-cyclopropyl-4-[2-(N-ethyl-N-methylsulphonyl)amino-4-methylsulphonylbenzoyl]isoxazole;  
 5-cyclopropyl-4-[3,4-dichloro-2-(N-methyl-N-methylsulphonyl)-aminobenzoyl]isoxazole;  
 5-cyclopropyl4-[2-(N-methyl-N-methylsulphonyl)amino-4-trifluoromethylbenzoyl]isoxazole;  
 5-cyclopropyl4-[2-(N-phenyl-N-methylsulphonyl)amino-benzoyl]isoxazole;  
 4-[4-bromo-2-(N-methyl-4-methylsulphonyl)amino-benzoyl]-5-cyclopropylisoxazole;  
 5-cyclopropyl-4-[2-(N-methyl-N-methylsulphonyl)amino-4-methylsulphonylbenzoyl]isoxazole;  
 ethyl 5-cyclopropyl4-[4-chloro-2-(N-methyl-N-methylsulphonylamino)benzoyl]isoxazole-3-carboxylate;  
 4-[4-chloro-2-(N-methyl-N-ethylsulphonylamino)benzoyl]-5-cyclopropyl-isoxazole;  
 5-cyclopropyl-4-[2,4bis(N-methyl-N-methylsulphonyl)-aminobenzoyl]isoxazole;  
 5-cyclopropyl [2-(N-methyl-N-methylsulphonyl)amino4-fluorobenzoyl]isoxazole;  
 -4-[2-bromo-4-(N-methyl-N-methylsulphonyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 4-[2-chloro-4-(N-methyl-N-methylsulphonyl)aminobenzoyl]-5-cycopropylisoxazole;  
 4-[3-chloro-2-(N-methyl-N-methylsulphonyl)amino-4-trifluoromethoxybenzoyl]-5-cyclopropylisoxazole;  
 5-cyclopropyl-4-[2-(N-methyl-N-methylsulphonyl)amino4-trifluoromethoxybenzoyl]isoxazole;  
 4-[5-chloro-2-(N-methyl-N-methylsulphonyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 5-cyclopropyl-4-[2-fluoro4(N-methyl-N-methylsulphonyl)aminobenzoyl]isoxazole;  
 5-cyclopropyl-4-[3,4-difluoro-2-(N-methyl-N-methylsulphonyl)aminobenzoyl]isoxazole;  
 5-cyclopropyl-4-[4,5-difluoro-2-(N-methyl-N-methylsulphonyl)aminobenzoyl]isoxazole;  
 5-cyclopropyl4-[4-iodo-2-(N-methyl-N-methylsulphonyl)aminobenzoyl]isoxazole;  
 4-[4-chloro-2-(N-isobutyl-N-methylsulphonyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 4-[4-chloro-2-(N-methyl-N-n-propylsulphonyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 4-[4-chloro-2-(N-methyl-N-phenylsulphonyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 4-[4-chloro-2-(N-benzylsulphonyl-N-methyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 4-[4-chloro-2-(N-methyl-N-isopropylsulphonyl)aminobenzoyl]-5-cyclopropylisoxazole;  
 4-[4-chloro-2-(N-methoxy-N-methylsulphonyl)aminobenzoyl]-5-cyclopropylisoxazole; or  
 ethyl 5-cyclopropyl4-[2-(N-methyl-N-methylsulphonyl)amino-4-trifluoromethylbenzoyl]isoxazole-3-carboxylate.  
 
     
     
         13 . A process for the preparation of a compound of formula (I) as defined in  claim 1  which comprises: 
 (a) where R represents hydrogen excluding compounds of formula (I) in which a group —XR 3  is in the ortho position and X is —NH—, reacting a compound of formula (II):  
                     
 wherein L is a leaving group and R 1 , R 2 , R 3 , a and X are as defined in  claim 1  provided that when X is —NH— the group —XR 3  is not in the ortho position of the phenyl ring, with hydroxylamine or a salt of hydroxylamine;  
 (b) where R represents hydrogen, reacting a compound of formula (m):  
                     
 wherein R 1  is as defined in  claim 1  and Y represents a carboxy group or a reactive derivative thereof or a cyano group, with an appropriate organometallic reagent;  
 (c) where R represents a group —CO 2 R 4  excluding compounds of formula (I) in which a group —XR 3  is in the ortho position and X is —NH—, reacting a compound of formula (IV)  
                     
 wherein R 1 , R 2   1  R 3 , X and n are as defined in  claim 1  provided that when X is —NH— the group —XR 3  is not in the ortho position of the phenyl ring, and P is a leaving group, with a compound of formula R 4 O 2 CC(Z)=NOH wherein R 4  is as defined in  claim 1  and Z is a halogen atom;  
 (d) where R represents a group —CO 2 R 4  excluding compounds of formula (I) in which a group —XR 3  is in the ortho position and X is —NH—, reacting a compound of formula (V):  
                     
 wherein R 1 , R 2 , R 3 , X and n are as defined provided that when X is —NH— the group —XR 3  is not in the ortho position of the phenyl ring, with a compound of formula R 4 O 2 CC(Z)=NOH wherein R 4  is as defined in  claim 1  and Z is a halogen atom;  
 (e) where R represents a group —CO 2 R 4  excluding compounds of formula (I) in which a group —XR 3  is in the ortho position and X is —NH—, reacting a salt of a compound of formula (VI):  
                     
 wherein R 1 , R 2 , R 3 , X and n are as defined in  claim 1  provided that when X is —NH— the group —XR 3  is not in the ortho position of the phenyl ring, with a compound of formula R 4 O 2 CC(Z)=NOH wherein R 4  is as defined in claim I and Z is a halogen atom;  
 (f) where X represents —NH—, deprotecting a compound of formula (VII):  
                     
 wherein R, R 1 , R 2  and n are as defined in  claim 1  and A represents —NX 1 R 3  wherein R 3  is as defined in  claim 1  and XI represents a protecting group which can be removed under acidic or neutral reaction conditions  
 (g) where p is one or two and/or q is the oxidation of the sulphur atom of the corresponding compound of formula (I) in which p is 0 or 1 and/or q is zero;  
 optionally followed by the conversion of the compound of formula (I) thus obtained into an agriculturally acceptable salt.  
 
     
     
         14 . A herbicidal composition which comprises as active ingredient a herbicidally effective amount of a 4-benzoylisoxazole derivative of formula (I) as defined in any one of  claims 1  to  11  or an agriculturally acceptable salt-thereof in association with an agriculturally acceptable diluent or carrier and/or surface active agent.  
     
     
         15 . A herbicidal composition according to  claim 14  in the form of an aqueous suspension concentrate, a wettable powder, a water soluble or water dispersible powder, a liquid water soluble concentrate, a liquid emulsifiable suspension concentrate, a granule or an emulsifiable concentrate.  
     
     
         16 . A method for controlling the growth of weeds at a locus which comprises applying to the locus a herbicidally effective amount of a 4-benzoylisoxazole derivative of formula (I) as defined in any one of  claims 1  to  11  or an agriculturally acceptable salt thereof.  
     
     
         17 . A method according to  claim 16  in which the locus is an area used, or to be used, for growing of crops and the compound is applied at an application rate from 0.01 kg to 4.0 kg per hectare.  
     
     
         18 . A compound of formula:  
       
         
           
           
               
               
           
         
         in which R, R 1 , R 2  and n are-as defined in  claim 1  and A represents —NX 1 R 3 , wherein R 3  is as defined in  claim 1  and X 1  represents a protecting group which can be removed under acidic or neutral reaction conditions.