Method of preparation of antiviral compounds and useful intermediates thereof

Abstract

The invention is directed to processes for synthesizing bicyclic nucleoside antiviral compounds and for synthesizing the intermediates used in the process. The invention is also directed to novel intermediate compounds useful in the process. The antiviral compounds are useful in the treatment of herpes zoster (i.e., varicella zoster virus, VZV, shingles) and for the prevention of post herpetic neuralgia (PHN) resulting from this viral infection.

1 . A compound selected from a compound of Formula (V), Formula (VI), Formula (VII), and Formula (VIII): 
       
         
           
           
               
               
           
         
         wherein:
 R 1  is C 1 -C 6  alkyl; 
 R 4  and R 5  are each independently H or C 1 -C 2  alkyl; 
 R 6  is an amino acid protecting group selected from the group consisting of Boc, Fmoc, and Cbz; 
 R 10  is trityl, 4,4′-dimethoxytrityl, diphenylmethylsilyl, tert-butyldimethylsilyl, or tert-butyldiphenylsilyl; and 
 R 11  is selected from
 C 1 -C 6  alkanoyl, 
 halogen substituted alkanoyl, 
 optionally substituted aroyl, 
 optionally substituted benzyl, 
 Cbz, and 
 diphenylmethyl.