4H-3,1-Benzoxazine derivatives

Abstract

4H-3,1-Benzoxazine derivatives of the formula ##STR1## where R 1 , R 2 and Y have the meanings given in the specification, and their use for controlling unwanted plant growth in numerous crops, such as cereals, Indian corn, soybeans and cotton.

We claim: 
     
       1. 4H-3,1-Benzoxazine derivatives of the formula ##STR526## where Y is oxygen or sulfur, .Iadd.R 2  is .Iaddend.Ar(R 6 ) n , Ar denoting phenyl, R 6  denoting haloalkoxy or haloalkylmercapto, each of 1 to 4 carbon atoms, and n being 1 or 2. 
     
     
       2. 2-(p-Trifluoromethoxy-phenyl)-3,1-benzoxazin-4-one. 
     
     
       3. 2-(m-Trifluoromethoxy-phenyl)-3,1-benzoxazin-4-one. 
     
     
       4. 2-(m-1',1',2',2'-Tetrafluoroethoxy-phenyl)-3,1-benzoxazin-4-one. 
     
     
       5. A herbicide comprising a solid and/or liquid inert carrier and a 4H-3,1-benzoxazine derivative of the formula I as claimed in claim 1. 
     
     
       6. A process for combating unwanted plant growth, wherein the plants or the soil are treated with a herbicidally effective amount of a 4H-3,1-benzoxazine derivative of the formula I as claimed in claim 1. 
     
     
       7. A compound as set forth in claim 1 wherein n is 1. 
     
     
       8. 2-(m-chlorodifluoromethoxy-phenyl)-3,1-benzoxazin-4-one. 
     
     
       9. 2-(m-trifluoromethylmercapto-phenyl)-3,1-benzoxazin-4-one. 
     
     
       10. 2-(m-chlorodifluoromethylmercapto-phenyl)-3,1-benzoxazin-4-one. .Iadd. 
     
     
       11.  4H-3,1-Benzoxazine derivatives of the formula ##STR527## where R 1  is fluorine or chlorine, Y is oxygen or sulfur and R 2  is phenyl. .Iaddend. .Iadd. 
     
     
       12.  A 4H-3,1-Benzoxazine derivative as in claim 1, wherein R 1  is fluorine and Y is oxygen. .Iaddend. .Iadd.13. A 4H-3,1-Benzoxazine derivative as in claim 1, wherein R 1  is chlorine and Y is oxygen. .Iaddend.