Process for preparation of benzylpiperidine compounds

Abstract

According to the process as shown in the following scheme having a step for reacting Compound (I) with Compound (II) to produce Compound (III), benzylpiperidine compounds useful as synthesis starting materials of pharmaceutical agents, agricultural chemicals and the like can be produced conveniently by a short step: wherein R 1 is a hydrogen atom or an amino-protecting group, R 2 is a hydrogen atom, a hydrocarbon group optionally having substituents, an alkoxy group optionally having substituents or a heterocyclic group optionally having substituents, and R 3 is a lower alkyl group.

1 . A process for the preparation of a compound represented by the formula:  
     
       
         
         
             
             
         
       
     
     wherein 
 R 2  is a hydrogen atom, a hydrocarbon group optionally having substituents, an alkoxy group optionally having substituents or a heterocyclic group optionally having substituents, and  
 R 3  is a lower alkyl group,  
 or a salt thereof, which comprises reacting a compound represented by the formula:  
                     
 wherein X 1  is a halogen atom and R 2  is as defined above, or a salt thereof, with a trialkyl phosphite represented by the formula:  
                     
 wherein R 3  is as defined above.  
 
   
   
       2 . The process of  claim 1 , wherein the compound represented by the formula (IV) or a salt thereof is reacted with the compound represented by the formula (V) in the presence of alkali metal iodide.  
   
   
       3 . The process of  claim 2 , wherein the alkali metal iodide is potassium iodide.  
   
   
       4 . A process for the preparation of a compound represented by the formula:  
     
       
         
         
             
             
         
       
     
     wherein 
 G 1  is a bond, CO or SO 2 ,  
 X 3  is a leaving group,  
 R 4  is a hydrogen atom, a hydrocarbon group optionally having substituents, a heterocyclic group optionally having substituents, an alkoxy group optionally having substituents, an aryloxy group optionally having substituents or an amino group optionally having substituents, and  
 R 5  is a cyclic hydrocarbon group optionally having substituents or a heterocyclic group optionally having substituents,  
 or a salt thereof, which comprises reacting a compound represented by the formula:  
                     
 wherein X 3  and R 5  are as defined above, or a salt thereof, with a compound represented by the formula:  
                     
 wherein G 1  and R 4  are as defined above, or a salt thereof.