Phosphonoderivative of purine with antiviral activity.

摘要

The (R)-isomer or the (S)-isomer of a compound of formula (IA), optionally in admixture with up to 45% of the mixture by weight of the corresponding (S)-isomer or the (R)-isomer respectively: <CHEM> wherein R1<1> is hydroxy or amino; R2<1> is amino or hydrogen; R3<1> is hydroxymethyl or acyloxymethyl; and R4 is a group of formula: <CHEM> wherein R5 and R6 are independently selected from hydrogen, C1-6 alkyl and optionally substituted phenyl; or R3 and R4 together are: <CHEM> wherein R6 is as defined above; having antiviral activity, a process for their preparation and their use in the treatment of viral infections or neoplastic diseases.