Method for preparing disubstituted piperidine and intermediates

Abstract

The disclosure relates to a method for preparing a compound of formula (I), wherein P 1 and P 2 are groups protecting the carboxylic acid and oxyamine functions, starting from pyroglutamic acid (S). The disclosure also relates to novel intermediates.

1 . A method for preparing the compound of formula (I) 
       
         
           
           
               
               
           
         
         wherein P 1  and P 2  represent groups protecting the carboxylic acid and oxyamine functions, comprising a beta-ketosulfoxonium compound of formula: 
       
       
         
           
           
               
               
           
         
         wherein P 1  is as defined here above and P 3  represents an amine protecting group, is treated with a reagent generating HCl, in order to obtain the compound of formula: 
       
       
         
           
           
               
               
           
         
         wherein P 1  and P 2  are as defined here above, which is treated without isolating it, with hydroxylamine derivative, in order to obtain the compound of formula: 
       
       
         
           
           
               
               
           
         
         wherein P 1  and P 3  are as defined here above and P 2  represents a protecting group of the oxime, the amine of which is de-protected by the action of an acid, in order to obtain the compound of formula: 
       
       
         
           
           
               
               
           
         
         wherein P 1  and P 2  are defined as here above, which is cyclized by the action of a base, in order to obtain the compound of formula: 
       
       
         
           
           
               
               
           
         
         wherein P 1  and P 2  are defined as here above, the oxime function of which is reduced by the action of a reducing agent, in order to obtain the expected compound of formula (I) which, if desired, is salified by the action of an acid. 
       
     
     
         2 . The method according to  claim 1 , wherein P 1  represents a benzyl group. 
     
     
         3 . The method according to  claim 1 , wherein P 3  represents a tert-butoxy-carbonyl group. 
     
     
         4 . The method according to  claim 1 , wherein P 2  represents a benzyl group. 
     
     
         5 . The method according to  claim 1 , wherein the compound of formula (b) is treated with lithium chloride in the presence of methane sulfonic acid. 
     
     
         6 . The method according to  claim 1 , wherein the amine of the compound of formula (III) is de-protected by the action of methane sulfonic acid, without prior isolation of this compound. 
     
     
         7 . The method according to  claim 1 , wherein the cyclization of the compound of formula (IV) is carried out by the action of sodium bicarbonate. 
     
     
         8 - 10 . (canceled)