Process for preparing pure anastrozole

Abstract

The present invention discloses two new related substances (6) and (7) of Anastrozole synthesis from Q.A. Salt (5) as in Scheme-1 and purification procedures to get Anastrozole (1) free from (6) and (7).

1 .- 5 . (canceled) 
     
     
         6 . A compound consisting essentially of Anastrozole with related substances of structural formula (6) and (7) removed therefrom, 
       
         
           
           
               
               
           
         
         the compound prepared by a process comprising the steps of:
 a. dissolving Anastrozole in an alcoholic solvent; 
 b. adding hydrocarbon to the alcoholic solution; and 
 c. isolating pure Anastrozole. 
 
       
     
     
         7 . A compound consisting essentially of Anastrozole, the compound prepared by a process comprising the steps of
 a. dissolving Anastrozole in an alcoholic solvent;   b. adding hydrocarbon to the alcoholic solution; and   c. isolating pure Anastrozole,   
       in which the impurity content of related substances of structures (6) & (7) is less than 0.1% 
       
         
           
           
               
               
           
         
       
     
     
         8 . The compound of  claim 7 , wherein the hydrocarbons added to the alcoholic solution are anti-solvent and are selected from a group consisting of aromatic hydrocarbons, and aliphatic hydrocarbons. 
     
     
         9 . The compound of  claim 8 , wherein the hydrocarbons are selected from a group consisting of C 1 -C 10 , straight chain, branched and cyclic hydrocarbons.