Substituted ester compound of nucleoside analogue

Abstract

A compound having the general formula (II): wherein X is 0, S, NH or CH2, Y is 0, S or NH, Z is 0, S or CH2, R1 is C1-6 alkyl, preferably n-alkyl, e.g., n pentyl or n-hexyl, and one of R2 and R3 is OH, and the other of R3 and R2 is a neutral, non-polar amino acid moiety. Said neutral, non-polar amino acid moiety R2 or R3 may be: in which R4, R5, R6 and R7 are each independently H or C1-2 alkyl. In preferred embodiments, one of R2 or R3 is valine, leucine, isoleucine or alanine, particularly valine.