Herbicidally active pyridyl-/pyrimidyl-pyrazine derivatives

Abstract

The present invention relates to herbicidally active pyridyl-/pyrimidyl-pyrazine derivatives, as well as to processes and intermediates used for the preparation of such derivatives. The invention further extends to herbicidal compositions comprising such derivatives, as well as to the use of such compounds and compositions in controlling undesirable plant growth: in particular the use in controlling weeds, in crops of useful plants.

1 . A compound of Formula (I) 
       
         
           
           
               
               
           
         
       
       (I) or a salt thereof,
 wherein: 
 X 1  is N or CR 1 ; 
 R 1  is selected from the group consisting of halogen, cyano, C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 1 -C 6 alkoxy, —C(O)OC 1 -C 6 alkyl, —S(O) p C 1 -C 6 alkyl, NR 6 R 7 , C 1 -C 6 haloalkoxy and C 1 -C 6 haloalkyl; 
 R 2  is selected from the group consisting of halogen, cyano, nitro, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, trimethylsilylC 2 -C 6 alkynyl-, C 3 -C 6 cycloalkyl, C 5 -C 6 cycloalkenyl, —C(O)OC 1 -C 6 alkyl, —S(O) p (C 1 -C 6 alkyl), C 1 -C 6 alkoxy, C 1 -C 6 haloalkoxy, —O—(CR a R b ) q R 9 , or phenyl; 
 R 3  is selected from the group consisting of hydrogen, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 2 -C 6 haloalkenyl, C 1 -C 6 alkoxyC 1 -C 3 alkyl-, C 1 -C 6 haloalkyl- and —(CR a R b ) q R 5 ; 
 R a  is hydrogen or C 1 -C 2  alkyl; 
 R b  is hydrogen or C 1 -C 2  alkyl; 
 R c  is hydrogen or C 1 -C 4 alkyl; 
 R 4  is selected from the group consisting of hydrogen, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 2 -C 6 haloalkenyl, C 1 -C 6 alkoxyC 1 -C 3 alkyl-, C 1 -C 6 haloalkyl- and —(CR a R b ) q R 5 ; 
 R 5  is hydroxy, —C(O)OC 1 -C 6 alkyl, —C 3 -C 10 cycloalkyl, -aryl and -heteroaryl wherein said aryl and heteroaryl are optionally substituted by 1 to 3 independent R 8 ; 
 or R 3  and R 4  together with the nitrogen to which they are attached, form a saturated or partially unsaturated 4-6 membered ring system optionally containing 1 or 2 further heteroatoms independently selected from S, O and N, wherein said ring is optionally substituted by 1 to 3 R 8 ; 
 R 6  and R 7  are independently selected from the group consisting of hydrogen, C 1 -C 6 alkyl and —C(O)OC 1 -C 6 alkyl; 
 each R 8  is independently selected from the group consisting of halogen, C 1 -C 6  alkyl and C 1 -C 6 alkoxy-, C 1 -C 6  haloalkyl, C 1 -C 6  haloalkoxy-, cyano and S(O) p (C 1 -C 6 alkyl); 
 R 9  is —C(O)OR c , —OC(O)R c , —C 3 -C 6 cycloalkyl, or an -aryl, -aryloxy, -heteroaryl, -heteroaryloxy or -heterocyclyl ring, wherein said ring is optionally substituted by 1 to 3 independent R 8 ; 
 n is 0 or 1; 
 p is 0, 1, or 2; and 
 q is 0, 1, or 2; 
 with the proviso that the compound of formula (I) is not: 
 (iii) methyl 6-(5-methyl-3-pyridyl)-3-morpholino-pyrazine-2-carboxylate, or 
 (iv) methyl 3-amino-6-(3-pyridyl)pyrazine-2-carboxylate. 
 
     
     
         2 . The compound of formula (I) according to  claim 1 , wherein X 1  is N. 
     
     
         3 . The compound of Formula (I) according to  claim 1 , wherein X 1  is CR 1  and R 1  is selected from the group consisting of cyano, fluoro, chloro, methoxy-, difluoromethoxy, and trifluoromethyl. 
     
     
         4 . The compound of Formula (I) according to  claim 1 , wherein R 2  is halogen, cyano, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 2 -C 4 alkenyl, C 2 -C 4 alkynyl, trimethylsilylC 2 -C 4 alkynyl-, —C(O)OC 1 -C 4 alkyl, —O—(CR a R b ) q R 9 , or phenyl. 
     
     
         5 . The compound of Formula (I) according to  claim 1 , wherein R 3  and R 4  are each independently selected from the group consisting of hydrogen, C 1 -C 4 alkyl, C 2 -C 4 alkenyl, C 2 -C 4 alkynyl, C 2 -C 4 haloalkenyl, C 2 -C 4 alkoxyC 1 -C 3 alkyl-, C 1 -C 4 haloalkyl- and —(CR a R b ) q R 5 . 
     
     
         6 . The compound of Formula (I) according to  claim 5 , wherein R 3  is hydrogen or methyl, and R 4  is selected from hydrogen, hydrogen, C 1 -C 4 alkyl, or —(CR a R b ) q R 5 . 
     
     
         7 . The compound of Formula (I) according to  claim 6 , wherein R 5  is hydroxy, C 3 -C 6 cycloalkyl, phenyl or a 5-10-membered heteroaryl ring system, wherein said phenyl or heteroaryl ring system is optionally substituted by 1-3 R 8 . 
     
     
         8 . The compound of Formula (I) according to  claim 7 , wherein R 5  hydroxy. 
     
     
         9 . The compound of Formula (I) according to  claim 1 , wherein R 3  and R 4  together with the nitrogen atom to which they are joined, form a saturated or partially unsaturated 5- or 6-membered ring system optionally containing from 1 or 2 further heteroatoms independently selected from S, O and N, wherein said ring is optionally substituted by 1 to 3 independent R 8 . 
     
     
         10 . The compound of Formula (I) according to  claim 9 , wherein R 3  and R 4  together with the nitrogen atom to which they are joined form a pyrrolinyl, pyrrolidinyl, pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, triazolyl, piperidyl, morpholinyl, thiomorpholinyl, and piperazinyl ring, each optionally substituted by 1 to 3 independent R 8 . 
     
     
         11 . A herbicidal composition comprising a compound of Formula (I) as defined in  claim 1  and an agriculturally acceptable formulation adjuvant. 
     
     
         12 . The herbicidal composition according to  claim 11 , further comprising at least one additional pesticide.