Synthesis of 2, 6-dicarbonylpyridines

Abstract

Synthesis of 2,6-dicarbonylpyridines in solution in a hydrocarbon medium is described. The hydrocarbon medium solutions of 2,6-dicarbonylpyridines may be used directly in further syntheses.

I claim:  
     
         1 . A process for the synthesis of 2,6-dicarbonylpyridine which comprises: 
 (i) converting 2,6-pyridine dicarboxylic acid to a solution of 2,6-pyridine dicarboxylic acid dichloride in a hydrocarbon;    (ii) treating said step (i) hydrocarbon solution of 2,6-pyridine dicarboxylic dichloride with a preformed mixture of bis(2-alkoxy alkyl) amine and trialkyl amine, 
 wherein a reaction mixture comprising a solution of 2,6-pyridine dicarboxamide in said step (i) hydrocarbon is produced;  
   (iii) treating said step (ii) reaction mixture solution with a compound of formula MZ, 
 wherein M is an alkali metal and Z is an alkyl or aryl group, and trialkylsilyl halide,  
 wherein a step (iii) reaction mixture is produced; and  
   (iv) treating said step (iii) reaction mixture with water 
 wherein a biphasic step (iv) reaction mixture is produced;  
 wherein said step (iv) reaction mixture comprises a lower aqueous layer and an upper organic layer, and  
 wherein said upper organic layer comprises a hydrocarbon solution of 2,6-dicarbonylpyridine.  
   
     
     
         2 . The method of  claim 1  further comprising a step 
 (v) utilizing said step (iv) hydrocarbon solution of 2,6-dicarbonylpyridine directly in a further synthesis.  
 
     
     
         3 . The method of  claim 1  wherein said step (i) converting is accomplished by treating said 2,6-pyridine dicarboxylic acid with a sulfonyl halide.  
     
     
         4 . The method of  claim 1  wherein said step (ii) preformed mixture contains about 2.0 mol of bis(methoxyethyl) amine and about 2.5 mol of ethyl amine.  
     
     
         5 . The method of  claim 1  wherein the lower aqueous layer and the upper organic layer of said step (iv) biphasic reaction mixture are separated, and wherein the separated lower aqueous layer is washed with toluene to extract 2,6-dicarbonylpyridine therefrom.  
     
     
         6 . A method which comprises: 
 (i) treating a 2,6-pyridine dicarboxylic dihalide in solution in a hydrocarbon medium with a bis(2-alkoxyalkyl) amine and a trialkyl amine, 
 wherein a reaction mixture containing 2,6-pyridine dicarboxamide in said hydrocarbon medium is produced.  
   
     
     
         7 . A method which comprises: 
 (i) treating a 2,6-pyridine dicarboxamide in solution in a hydrocarbon medium with a compound of formula MZ in which M is any alkali metal and Z is any alkyl or aryl group, 
 wherein a first reaction mixture is produced,  
   (ii) treating said step (i) first reaction mixture with a trialkylsilyl halide, 
 wherein a second reaction mixture is produced, and  
   (iii) treating said step (ii) second reaction mixture with water, 
 wherein a biphasic solution having an organic upper layer and an aqueous lower layer is produced, and  
 wherein said organic upper layer comprises a solution of a 2,6-dicarbonylpyridine in said step (i) hydrocarbon medium.  
   
     
     
         8 . A method which comprises: 
 (i) providing a slurry of 2,6-pyridine dicarboxylic acid in toluene;    (ii) converting said 2,6-pyridine dicarboxylic acid in situ in solution in said toluene to 2,6-pyridine diacetyl dichloride, 
 wherein a solution of 2,6-pyridine diacetyl dichloride in toluene is produced;  
   (iii) converting said step (ii) solution to a step (iii) solution of 2,6-pyridine dicarboxamide in said toluene; and    (iv) converting said step (iii) 2,6-pyridine dicarboxamide in situ in solution in said step (iii) toluene to 2,6-diacetylpyridine.    
     
     
         9 . The method of  claim 8  further comprising a step 
 (v) treating said 2,6-diacetylpyridine in situ in said step (iv) toluene solution with a 2,4,6-alkyl aniline.