Preparation of terpyridines

Abstract

The present invention provides processes for preparing terpyridine compounds. In particular, the present invention provides a process for the preparation of a C 1 -C 4 -alkyl pyridine-2-carboxylate compound, a 1,5-bis(2-pyridyl)pentane-1,3,5-trione compound, and a 2,6-bis(2-pyridyl)-4(1H)pyridinone compound.

1 .- 7 . (Cancelled).  
     
     
         8 . A process for preparing a C 1 -C 4 -alkyl pyridine-2-carboxylate compound of the formula a  
       
         
           
           
               
               
           
         
       
       in which 
 R is hydrogen or a C 1 -C 12 -alkyl or C 1 -C 12 -alkox radical and  
 n is 0, 1, 2, 3 or 4,  
 by acid hydrolysis of a 2-cyanopyridine compound of the formula a′ 
                     
 by means of an anhydrous inorganic acid or its anhydride in the presence of water and a C 1 -C 4 -alkanol, wherein an equimolar amount of water is added to the 2-cyanopyridine compound of the formula a′ prior to addition of the anhydrous inorganic acid or its anhydride.  
 
     
     
         9 . A process for preparing a 1,5-bis(2-pyridyl)pentane-1,3,5-trione compound of the formula b  
       
         
           
           
               
               
           
         
       
       in which 
 R are hydrogens or identical C 1 -C 12 -alkyl or C 1 -C 12 -alkoxy radicals and  
 n is 0, 1, 2, 3 or 4 and is the same for both sets of radicals R,  
 by condensation of the C 1 -C 4 -alkyl pyridine-2-carboxylate compound of the formula a  
                     
 with acetone in an aprotic solvent in the presence of an alkali metal C 1 -C 4 -alkoxide or alkaline earth metal C 1 -C 4 -alkoxide as base.  
 
     
     
         10 . A process as claimed in  claim 9 , wherein the base used is an alkali metal C 1 -C 4 -alkoxide.  
     
     
         11 . A process as claimed in  claim 9 , wherein the base used is sodium C 1 -C 4 -alkoxide.  
     
     
         12 . A process as claimed in  claim 9 , wherein the base used is sodium methoxide.  
     
     
         13 . A process for preparing a 2,6-bis(2-pyridyl)-4(1H)pyridinone compound of the formula c  
       
         
           
           
               
               
           
         
       
       in which 
 R are hydrogens or identical C 1 -C 12 -alkyl or C 1 -C 12 -alkoxy radicals,  
 n is 0, 1, 2, 3 or 4 and is the same for both sets of radicals R,  
 Z is NH or NH 2   ⊕ [Y 1/q ] ⊖ and  
 Y is the anion of a q-basic acid H q Y,  
 by reacting the 1,5-bis(2-pyridyl)pentane-1,3,5-trione compound of the formula b  
                     
 with ammonia or ammonium salts (NH 4 ) q Y with removal of the water of reaction formed, wherein the removal of the water of reaction is carried out using a C 1 -C 4 -alkanol as entrainer.  
 
     
     
         14 . A process as claimed in  claim 13 , wherein the removal of the water of reaction is carried out using ethanol, n-propanol, i-propanol or n-butanol as entrainer.  
     
     
         15 . A process as claimed in  claim 13 , wherein the removal of the water of reaction is carried out using ethanol as entrainer.  
     
     
         16 .- 17 . (Cancelled)