Processes and intermediates for preparing anti-hiv agents

Abstract

The invention provides synthetic processes and synthetic intermediates that can be used to prepare compounds having useful anti-HIV properties.

1 - 56 . (canceled) 
     
     
         57 . A method of preparing a compound of formula 4a: 
       
         
           
           
               
               
           
         
       
       or a salt thereof, comprising reacting a corresponding compound of formula 2a: 
       
         
           
           
               
               
           
         
       
       with a corresponding compound of formula 3a: 
       
         
           
           
               
               
           
         
       
       or a salt thereof, to provide the compound of formula 4a or the salt thereof, wherein each R 1  is independently —C(═O)(C 1 -C 6 )alkyl, —C(═O)(C 3 -C 7 )cycloalkyl or —C(═O)aryl, wherein —C(═O)(C 3 -C 7 )cycloalkyl or —C(═O)aryl is optionally substituted with 1, 2 or 3 (C 1 -C 6 )alkyl groups; and provided the compound of formula 3a is not a sodium salt of 3a when the R 1  group of the compound of formula 3a is benzoyl. 
     
     
         58 . The method of  claim 57 , wherein R 1  is C(═O)aryl. 
     
     
         59 . The method of  claim 57 , wherein R 1  is benzoyl. 
     
     
         60 . The method of  claim 57 , wherein the compound of formula 2a is compound 2: 
       
         
           
           
               
               
           
         
       
     
     
         61 . The method of  claim 57 , wherein the compound of formula 3a is compound 3: 
       
         
           
           
               
               
           
         
       
     
     
         62 . The method of  claim 57 , wherein the reacting of compound of formula 2a with the compound of formula 3a is carried out in a solvent selected from polar solvent and non-polar solvent, or a combination thereof. 
     
     
         63 . The method of  claim 61 , wherein the solvent is selected from methylene chloride, tetrahydrofuran, N-methylpyrrolidinone, acetonitrile, methyl t-butyl ether, isopropyl acetate, and toluene, or a combination thereof. 
     
     
         64 . The method of  claim 57 , wherein t the reacting of compound of formula 2a with the compound of formula 3a is carried out at a temperature of about 60° C. to 70° C.