Process for the preparation of linezolid

Abstract

The present invention relates to an improved process for the preparation of Linezolid. More specifically, the present invention relates to an improved process for preparing (S)—N-[[3-[3-fluoro-4-[4-morpholinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl] phthalimide and (S)-glycidyl phthalimide intermediates, which are used in the preparation of Linezolid.

We claim: 
     
       1. A process for the preparation of the compound of formula (I) 
       
         
           
           
               
               
           
         
         comprising the steps of
 a) reacting a compound of formula (III) with (S)-Glycidylphthalimide of formula (IX) in the presence of an alkali metal iodide or a metal hydride to give the compound of formula (VI) 
 
       
       
         
           
           
               
               
           
         
         wherein R represents hydrogen, C 1 -C 5  alkyl, aryl, or aralkyl
 b) treating the compound of formula (VI) with aqueous methyl amine or hydrazine hydrate, 
 c) acylating the product of step b) with an acylating agent, and 
 d) isolating the compound of formula (I). 
 
       
     
     
       2. The process according to  claim 1 , wherein the alkali metal iodide is selected from the group consisting of lithium iodide, sodium iodide and potassium iodide; wherein the metal hydride is selected from the group consisting of lithium hydride, sodium hydride and magnesium hydride; and wherein the acylating agent is selected from the group consisting of acetic anhydride and acetyl chloride. 
     
     
       3. The process according to  claim 1 , wherein step a) is carried out in the presence of a solvent selected from the group consisting of alcohols, ketones, halogenated solvents, esters, hydrocarbon solvents, ethers, amides, and dimethyl sulfoxide.