Calcium (3S) tetrahydro-3-furanyl (1S,2R)-3-[[(4-aminophenyl)sulfonyl](isobutyl)amino]-1-benzyl-2-(phos-phonooxy)propylcarbamate

Abstract

The invention relates to calcium (3S) tetrahydro-3-furanyl(1S,2R)-3-[[(4-aminophenyl)sulfonyl](isobutyl)amino]-1-benzyl-2-(phosphonooxy)propylcarb-amate, to processes for its preparation, and to its use in the treatment of diseases caused by retroviruses.

1 . A process for the preparation of a compound of formula (I) in a crystalline form,  
       
         
           
           
               
               
           
         
       
       comprising the reduction of a compound of formula (IV),  
       
         
           
           
               
               
           
         
       
       in the presence of a suitable reducing agent in a suitable solvent, followed by adding water and a source of calcium ions:  
     
     
         2 . A process for the preparation of a compound of formula (I) as claimed in  claim 1 , wherein the reducing agent is hydrogen with a palladium on carbon catalyst.  
     
     
         3 . A process for the preparation of a compound of formula (I) as claimed in  claim 1 , wherein the calcium ion source is calcium acetate.  
     
     
         4 . A process for the preparation of a compound of formula (I) as claimed in  claim 1 , additionally comprising recrystallising the compound from an appropriate solvent.  
     
     
         5 . A process for the preparation of a compound of formula (I) as claimed in  claim 4 , wherein the solvent is a mixture of industrial methylated spirit and water.  
     
     
         6 . A process for the preparation of a compound of formula (I) as claimed in  claim 1 , additionally comprising heating the product in water to a temperature in the range 70 to 99° C. for 2.5 to 6 hours, then cooling to ambient temperature and harvesting to solid.