Method for producing salts of tolperisone

Abstract

The invention relates to a method for producing an acid addition salt of 2,4′-dimethyl-3-piperidino-propiophenone (tolperisone) with a pharmaceutically acceptable acid, of the formula (I). According to the invention, 4-methylpropiophenone is reacted with piperidine hydrochloride and 1,2-dioxolane in the presence of an acid serving as a catalyst, and the tolperisone obtained in the form of an acid addition salt is separated by filtering after the reaction mixture has cooled down.

1 . Method for manufacturing pharmaceutically acceptable acid addition salts of 2,4′-dimethyl-3-piperidinopropiophenone (tolperisone), of formula (A) 
       
         
           
           
               
               
           
         
       
       said acid addition salts having a formula (B) 
       
         
           
           
               
               
           
         
       
       characterized by the fact that 4-methylpropiophenone of the formula 
       
         
           
           
               
               
           
         
       
       is reacted with piperidine hydrochloride of the formula 
       
         
           
           
               
               
           
         
       
       and 1,2-dioxolane of the formula 
       
         
           
           
               
               
           
         
       
       in presence of an acid serving as a catalyst, and the tolperisone obtained in the form of an acid addition salt is separated by filtering after the reaction mixture has cooled down. 
     
     
         2 . Method according to  claim 1 , characterized by the fact that the reaction is carried out in the presence of catalytic quantities of an acid, in particular aqueous hydrochloric acid. 
     
     
         3 . Method according to  claims 1  or  2 , characterized by the fact that the reaction is carried out in a solvent. 
     
     
         4 . Method according to  claim 3 , characterized by the fact that the reaction is preferably accomplished in 1,2-dioxolane as a solvent in a concentration range from 1 to 6 preferably 3.6 mol/lit. 
     
     
         5 . Method according to  claims 1  to  4 , characterized by the fact that the resulting tolperisone with the inorganic acid, such as hydrochloric acid is converted, into the addition salt. 
     
     
         6 . Method according to  claims 1  to  5 , characterized by the fact that tolperisone is isolated as an addition salt by addition to the reaction mixture of at least a solvent, such as ethyl acetate and methyl tert-butyl-ether.