Pyrazole derivative, intermediate therefor, processes for producing these, and herbicide containing these as active ingredient

Abstract

The present invention provides a pyrazole derivative of the general formula (1), which has an excellent efficacy as an active component for a herbicide, an intermediate for the production thereof, processes for the production thereof, and a herbicide containing the derivative as an active ingredient.

1 . A pyrazole derivative of the general formula (2), 
     
       
         
         
             
             
         
       
       wherein R 1  is a hydrogen atom, 
       an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted cycloalkyl group having 3 to 8 carbon atoms, 
       an alkyloxycarbonyl group having 1 to 6 carbon atoms or 
       an optionally substituted phenyl group, 
       R 2  is a hydrogen atom, 
       a halogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and 
       R 5  is an optionally substituted phenyl group or 
       an optionally substituted pyridyl group. 
     
   
   
       2 . A process for the preparation of a pyrazole derivative of  claim 1 ,
 which comprises reacting a 3-hydroxypyrazole derivative of the general formula (3),   
     
       
         
         
             
             
         
       
       and a compound of the general formula (4), wherein R 1  is a hydrogen atom, 
       an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted cycloalkyl group having 3 to 8 carbon atoms, 
       an alkyloxycarbonyl group having 1 to 6 carbon atoms or 
       an optionally substituted phenyl group, and wherein R 2  is a hydrogen atom, 
       a halogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and
   R 5 —Z  (4) 
 wherein R 5  is an optionally substituted phenyl group or 
 
       an optionally substituted pyridyl group, and wherein Z is a leaving group, 
       in the presence of a base. 
     
   
   
       3 . The process of  claim 2 , wherein R 5  in the general formula (4) is a phenyl group or a pyridyl group substituted with an electron-withdrawing group such as a halogen atom, a haloalkyl group, a cyano group or a nitro group. 
   
   
       4 . A process for the preparation of a pyrazole derivative of the general formula (1a) in the present invention, 
     
       
         
         
             
             
         
       
     
     wherein
 R 1  is a hydrogen atom, 
 an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted cycloalkyl group having 3 to 8 carbon atoms, 
 an alkyloxycarbonyl group having 1 to 6 carbon atoms or 
 an optionally substituted phenyl group, 
 R 2  is a hydrogen atom, 
 a halogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and 
 R 5a  is an optionally substituted phenyl group or an optionally substituted pyridyl group, 
 Y is an oxygen atom or a sulfur atom, and 
 R 3a  is an optionally substituted alkyl group having 1 to 12 carbon atoms, 
 an optionally substituted cycloalkyl group having 3 to 8 carbon atoms, 
 an optionally substituted aralkyl group having 7 to 11 carbon atoms, 
 an optionally substituted alkenyl group having 3 to 6 carbon atoms, 
 an optionally substituted alkynyl group having 3 to 6 carbon atoms, 
 an optionally substituted phenyl group, 
 an optionally substituted alkyloxy group having 1 to 6 carbon atoms, 
 an optionally substituted cycloalkyloxy group having 3 to 8 carbon atoms, 
 an optionally substituted aralkyloxy group having 7 to 11 carbon atoms, 
 an optionally substituted alkenyloxy group having 3 to 6 carbon atoms, 
 an optionally substituted alkynyloxy group having 3 to 6 carbon atoms or 
 an optionally substituted phenyloxy group,
 which comprises reacting a pyrazole derivative of the general formula (2c), 
 
 
     
       
         
         
             
             
         
       
       
         wherein R 1 , R 2  and R 5a  are as defined above, 
       
       and isocyanate or isothiocyanates of the general formula (5),
   R 3a —NCY  (5) 
 wherein R 3a  and Y are as defined above, 
 
       optionally in the presence of a base.