Methanesulfonate salts of abiraterone-3-esters and recovery of salts of abirater one-3-esters from solution in methyl tert-butyl ether

Abstract

A salt of a compound of formula (I) may be made with methanesulfonic acid. The salt and salts with other acids may be prepared by recovering from methyl tert-butyl ether (MTBE).

1 . The salt of a compound of formula (I): 
       
         
           
           
               
               
           
         
         where R′ represents a lower acyl group having 2 to 4 carbon atoms and R represents a hydrogen atom or an alkyl group of 1-4 carbon atoms; 
         with methanesulfonic acid. 
       
     
     
         2 . A salt as claimed in  claim 1  in which R′ represents a lower acyloxy group. 
     
     
         3 . A salt as claimed in  claim 1  in which R represents a hydrogen atom. 
     
     
         4 . A process for the preparation of a salt as claimed in  claim 1  by recovering the salt from a solution of the free base in any suitable solvent by treating the solution with methanesulfonic acid. 
     
     
         5 . A process as claimed in  claim 4  in which the solvent comprises an ester or an ether. 
     
     
         6 . A process as claimed in  claim 5  in which the solvent comprises methyl tert-butyl ether (MTBE). 
     
     
         7 . A process for the preparation of a compound of formula (I): 
       
         
           
           
               
               
           
         
         where R′ represents hydrogen or a lower acyl group having 2 to 4 carbon atoms and R represents a hydrogen atom or an alkyl group of 1-4 carbon atoms; 
         or a pharmaceutically acceptable salt thereof; 
         including the step of recovering a salt of the compound, where R′ represents a lower acyl group having 2 to 4 carbon atoms and R is as defined above, from methyl tert-butyl ether (MTBE). 
       
     
     
         8 . A process as claimed in  claim 7  in which the acid is hydrochloric, sulfuric or toluoyltartaric or methanesulfonic acid. 
     
     
         9 . A salt as claimed in  claim 7  in which R′ represents a lower acyloxy group. 
     
     
         10 . A salt as claimed in  claim 7  in which R represents a hydrogen atom.