Abstract: Compounds of formula (I) and pharmaceutically acceptable salts thereof: ##STR1## wherein R.sub.1 is hydrogen or hydroxy; andR.sub.2 is C.sub.1-6 alkyl;which are pro-drugs for 9-(3-hydroxyprop-1-oxy)guanine having antiviral activity, a process for their preparation and their use as pharmaceuticals.

Abstract: Compounds of formula (II): ##STR1## wherein R.sub.4 ' is R.sub.4 whereinR.sub.4 is hydrogen, hydroxy, amino or OR.sub.5 whereinR.sub.5 is C.sub.1-6 alkyl, phenyl or phenyl C.sub.1-2 alkyl either of which phenyl moieties may be substituted by one or two halo, C.sub.1-4 alkyl or C.sub.1-4 alkoxy groups;or R.sub.4 ' is a group or atom convertible to R.sub.4 ; andR.sub.x is amino or protected amino;which are useful intermediates in the preparation of purine derivatives having antiviral activity.

Abstract: Compounds of formula (I), and pharmaceutically acceptable salts thereof: ##STR1## wherein R.sub.1 is hydrogen or CH.sub.2 OH;R.sub.2 is hydrogen or, when R.sub.1 is hydrogen, hydroxy or CH.sub.2 OH;R.sub.3 is CH.sub.2 OH or, when R.sub.1 and R.sub.2 are both hydrogen, CH(OH)CH.sub.2 OH;R.sub.4 is hydrogen, hydroxy, amino or OR.sub.5 whereinR.sub.5 is C.sub.1-6 alkyl, phenyl or phenyl C.sub.1-2 alkyl either of which phenyl moieties may be substituted by one or two halo, C.sub.1-4 alkyl or C.sub.1-4 alkoxy groups;and in which any OH groups in R.sub.1, R.sub.2 and R.sub.3 may be in the form of O-acyl, phosphate, cyclic acetal or cyclic carbonate derivatives thereof; having antiviral activity.

Abstract: A process for the preparation of compounds of formula (I), and pharmaceutically acceptable salts thereof: ##STR1## wherein R.sub.1 is hydrogen or CH.sub.2 OH;R.sub.2 is hydrogen or, (when R.sub.1 is hydrogen), hydroxy or CH.sub.2 OH;R.sub.3 is CH.sub.2 OH or, (when R.sub.1 and R.sub.2 are both hydrogen), CH(OH)CH.sub.2 OH;R.sub.4 is hydrogen, hydroxy, amino or OR.sub.5whereinR.sub.5 is C.sub.1-6 alkyl, phenyl or phenyl C.sub.1-2 alkyl either of which phenyl moieties may be substituted by one or two halo, C.sub.1-4 alkyl or C.sub.1-4 alkoxy groups;and in which any OH groups in R.sub.1, R.sub.2 and/or R.sub.3 may be in the form of O-acyl, phosphate, cyclic acetal or cyclic carbonate derivatives thereof;which process comprises the reaction of a compound of formula (II): ##STR2## wherein R.sub.4 ' is R.sub.4 or a group or atom convertible thereto and R.sub.x is amino or protected amino; with a compound of formula (III):R.sub.3 'CHR.sub.2 'CHR.sub.1 'Q (III)wherein Q is a leaving group and R.sub.1 ', R.sub.