Novel process

Abstract

Compounds of structure (1) are obtained by reduction of compounds of the structures (2a), (2b), (4a), (4b). Compounds of structure (1), especially where Z is a hydrogen atom or a 3,4-methylenedioxyphenyl group, are important intermediates for inter alia paroxetine.

What is claimed is:  
     
         1 . A process for the preparation of 4-aryl-piperidines of structure (1)  
       
         
           
           
               
               
           
         
         in which R is hydrogen or an alkyl, aralkyl, aryl, acyl, alkoxycarbonyl, arylalkoxycarbonyl, aryloxycarbonyl group, and Z′ is a 3,4-methylenedioxyphenyl group,  
         which comprises reduction of a compound of structure (2a) or (2b)  
         
           
             
             
                 
                 
             
           
         
         in which Y is oxygen or sulphur, and 
 R and X are as defined above and Z is hydrogen or an alkyl, aralkyl or aryl group, and where Z is ocher than a 3,4-methylenedioxyphenyl group thereafter converting Z to 3,4-methylenedioxyphenyl.  
 
       
     
     
         2 . A process for the preparation of 4-aryl-piperidines of structure (1)  
       
         
           
           
               
               
           
         
         in which R is hydrogen or an alkyl, aralkyl, aryl, acyl, alkoxycarbonyl, arylalkoxycarbonyl, aryloxycarbonyl group, and Z is hydrogen or an alkyl, aralkyl or aryl group, most suitably where Z is a hydrogen atom or a 3,4-methylenedioxyphenyl group,  
         which comprises reduction of a compound of structure (2a) or (2b)  
         
           
             
             
                 
                 
             
           
         
         in which Y is oxygen or sulphur, and R, X, and Z are as defined above.  
       
     
     
         3 . A process according to  claim 1 , in which the reduction is carried out by catalytic hydrogenation at atmospheric or above atmospheric pressure or using hydride reagents.  
     
     
         4 . A process according to  claim 1 , in which a compound of structure (1) in which Z is alkyl, aralkyl or aryl is prepared by selective reduction of the ester group in a compound of structure (2a) or (2b) in which Z is alkyl, aralkyl or aryl.  
     
     
         5 . A process for the preparation of 4-aryl-piperidines of structure (1)  
       
         
           
           
               
               
           
         
         in which R is hydrogen or an alkyl, aralkyl, aryl, acyl, alkoxycarbonyl, arylalkoxycarbonyl, aryloxycarbonyl group, and Z is hydrogen or an alkyl, aralkyl or aryl group, especially a hydrogen atom or a 3,4-methylenedioxyphenyl group,  
         which comprises reduction of a compound of structure (4a) or (4b)  
         
           
             
             
                 
                 
             
           
         
         where X is one or more of hydrogen or a readily reducible group such as chlorine, bromine or iodine, and 
 R and Z are as defined above.  
 
       
     
     
         6 . A process according to  claim 1 , in which the reduction is accomplished by catalytic hydrogenation at atmospheric or above atmospheric pressure or using hydride reagents.  
     
     
         7 . A compound of structure (2a) or (2b)  
       
         
           
           
               
               
           
         
         in which Y is oxygen or sulphur, and 
 R, X, and Z are as defined in  claim 1 .  
 
       
     
     
         8 . A compound of structure (4a) or (4b)  
       
         
           
           
               
               
           
         
         in which R, X, and Z are as defined in  claim 1   
       
     
     
         9 . A compound of structure (4c) or (4d)  
       
         
           
           
               
               
           
         
         in which R and X are as defined in  claim 1   
       
     
     
         10 . A compound of structure (1)  
       
         
           
           
               
               
           
         
         in which R is hydrogen and Z is 3,4-methylenedioxyphenyl, whenever obtained by  
         (a) a process according to  claim 1 , or  
         (b) condensing a compound in which Z is hydrogen obtained by a process according to  claim 1  with 3,4-methylenedioxyphenol,  
         and where necessary removing a group R that is other than hydrogen.  
       
     
     
         11 . A compound according to  claim 9 , in the form of a hydrochloride salt.  
     
     
         12 . A method of treating the Disorders which comprises administering an effective or prophylactic amount of a compound as claimed in  claim 9  to a person suffering from one or more of the Disorders.