Process for the preparation of 2,3-pyridinedicarboximides

Abstract

There is provided a process for the preparation of 2,3-pyridinedicarboximides having the structural formula I The 2,3-pyridinedicarboximides are useful as intermediates in the preparation of herbicidal 2-(2-imidazolin-2-yl)nicotinic acids, esters and salts.

We claim:  
     
         1 . A process for the preparation of a 2,3-pyridinedicarboximide having the structural formula I  
       
         
           
           
               
               
           
         
       
       wherein 
 R is hydrogen, C 1 -C 6 alkyl or C 1 -C 6 alkoxymethyl;  
 R 1  is hydrogen, C 1 -C 6 alkyl, C(O)R 2 , 
 phenyl optionally substituted with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups,  
 benzyl optionally substituted on the phenyl ring with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups, or  
                     
 
 R 2  is C 1 -C 6 alkyl, benzyl or 
 phenyl optionally substituted with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups;  
 
 R 3  and R 4  are each independently C 1 -C 4 alkyl; and  
 R 5  is cyano or CONH 2 ,  
 which process comprises reacting an oxime or hydrazone having the structural formula II  
                     
 wherein  
 R is as described above;  
 R 6  is C 1 -C 6 alkyl;  
 R 7  is OR 8  or NR 9 R 10 ;  
 R 8  is hydrogen, C 1 -C 6 alkyl, C(O)R 11 , 
 phenyl optionally substituted with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups, or  
 benzyl optionally substituted on the phenyl ring with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups;  
 
 R 11  is C 1 -C 6 alkyl, OR 12 , NR 12 R 13 , benzyl or 
 phenyl optionally substituted with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups;  
 
 R 12  and R 13  are each independently hydrogen, C 1 -C 6 alkyl, benzyl or 
 phenyl optionally substituted with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups; and  
 
 R 9  and R 10  are each independently hydrogen, C 1 -C 6 alkyl, benzyl or 
 phenyl optionally substituted with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups,  
 with a maleimide having the structural formula III  
                     
 wherein R 1  is as described above.  
 
 
     
     
         2 . The process according to  claim 1  wherein 
 R is hydrogen, C 1 -C 4 alkyl or C 1 -C 4 alkoxymethyl;  
 R 1  is hydrogen, C 1 -C 4 alkyl, 
 phenyl optionally substituted with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups, or  
                     
 
 R 6  is C 1 -C 4 alkyl;  
 R 7  is OR 8 ; and  
 R 8  is hydrogen or C 1 -C 6 alkyl.  
 
     
     
         3 . The process according to  claim 2  wherein 
 R is hydrogen, methyl, ethyl or methoxymethyl;  
 R 1  is methyl, phenyl or  
                     
 R 6  is methyl or ethyl; and  
 R 8  is hydrogen or methyl.  
 
     
     
         4 . The process according to  claim 1  wherein the formula II oxime or hydrazone is reacted with the formula III maleimide in the presence of a solvent.  
     
     
         5 . The process according to  claim 2  wherein the solvent is selected from the group consisting of an aromatic hydrocarbon, a halogenated aromatic hydrocarbon, a polynuclear aromatic hydrocarbon, a glycol, an alkanoic acid, an alkanoic acid/water mixture, acetonitrile, an acetonitrile/water mixture, and mixtures thereof, and the boiling point of the solvent is at least about 60° C.  
     
     
         6 . The process according to  claim 5  wherein the solvent is selected from the group consisting of toluene, a xylene, mesitylene, acetonitrile, an acetonitrile/water mixture, acetic acid and mixtures thereof.  
     
     
         7 . The process according to  claim 6  wherein the solvent is toluene or acetonitrile.  
     
     
         8 . The process according to  claim 1  wherein the formula II oxime is reacted with the formula III maleimide at a temperature of about 60° C. to 160° C.  
     
     
         9 . The process according to  claim 8  wherein the temperature is about 75° C. to 135° C.  
     
     
         10 . The process according to  claim 1  wherein the formula II hydrazone is reacted with the formula III maleimide at a temperature of about 20° C. to 160° C.  
     
     
         11 . The process according to  claim 10  wherein the temperature is about 20° C. to 135° C.  
     
     
         12 . The process according to  claim 1  further comprising a Lewis acid.  
     
     
         13 . The process according to  claim 12  wherein the Lewis acid is aluminum chloride or titanium(IV) chloride.  
     
     
         14 . The process according to  claim 1  further comprising a base when R is C 1 -C 6 alkoxymethyl.  
     
     
         15 . The process according to  claim 14  wherein the base is selected from the group consisting of a tri(C 2 -C 4 alkyl)amine, an alkali metal acetate and mixtures thereof.  
     
     
         16 . A compound having the structural formula  
       
         
           
           
               
               
           
         
       
       wherein 
 R is hydrogen, C 1 -C 6 alkyl or C 1 -C 6 alkoxymethyl;  
 R 6  is C 1 -C 4 alkyl;  
 R 8  is hydrogen, C 1 -C 6 alkyl, C(O)R 11 . 
 phenyl optionally substituted with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups, or  
 benzyl optionally substituted on the phenyl ring with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or -cyano groups;  
 
 R 11  is C 1 -C 6 alkyl, OR 12 , NR 12 R 13 , benzyl or 
 phenyl optionally substituted with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups; and  
 
 R 12  and R 13  are each independently hydrogen, C 1 -C 6 alkyl, benzyl or 
 phenyl optionally substituted with any combination of from one to four halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, nitro or cyano groups, and  
 the cis and trans isomers thereof.  
 
 
     
     
         17 . The compound according to  claim 16  wherein 
 R is hydrogen, C 1 -C 4 alkyl or C 1 -C 4 alkoxymethyl;  
 R 6  is C 1 -C 4 alkyl; and  
 R 8  is hydrogen or C 1 -C 6 alkyl.  
 
     
     
         18 . The compound according to  claim 17  wherein 
 R is hydrogen, methyl, ethyl or methoxymethyl;  
 R 6  is methyl or ethyl; and  
 R 8  is hydrogen or methyl.  
 
     
     
         19 . The compound according to  claim 18  selected from the group consisting of 
 the O-methyloxime of 3-ethoxy-2-methyl-2-propen-1-one;  
 the O-methyloxime of  3 -methoxy-2-(methoxymethyl)-2-propen-1-one;  
 the oxime of 3-ethoxy-2-methyl-2-propen-1-one; and  
 the oxime of 3-methoxy-2-(methoxymethyl)-2-propen-1-one.  
 
     
     
         20 . A process for the preparation of a herbicidal imidazolinone compound having the formula XII  
       
         
           
           
               
               
           
         
       
       wherein 
 R is as defined in  claim 1;   
 R 14  is C 1 -C 4  alkyl;  
 R 15  is C 1 -C 4  alkyl, C 3 -C 6  cycloalkyl or R 14  and R 15  when taken together with the atom to which they are attached, represent a C 3 -C 6  cycloalkyl group optionally substituted with methyl and  
 R 16  is hydrogen, diloweralkylimino,  
 C 1 -C 12  alkyl optionally substituted with one of the following groups: C 1 -C 3  alkoxy, halogen, hydroxy, C 3 -C 6  cycloalkyl, benzyloxy, furyl, phenyl, halophenyl, lower alkylphenyl, lower alkoxyphenyl, nitrophenyl, carboxyl, loweralkoxycarbonyl, cyano or triloweralkylammonium;  
 C 3 -C 12  alkenyl optionally substituted with one of the following groups: C 1 -C 3  alkoxy, phenyl, halogen or loweralkoxycarbonyl or with two C 1 -C 3  alkoxy groups or two halogen groups;  
 C 3 -C 6  cycloalkyl optionally substituted with one or two C 1 -C 3  alkyl groups; or  
 a cation  
 which process comprises:  
 (a) preparing a compound having the formula I  
                     
 wherein R and R 1  are as defined in  claim 1  by a process as claimed in  claim 1;  and  
 (b) converting the compound having formula I into the compound having the formula XII.