Hydroxymethyl cyclobutyl purines

A compound having the formula ##STR47## and its pharmaceutically acceptable salts wherein R.sub.1 is ##STR48## wherein R.sub.2 is hydrogen, --PO.sub.3 H.sub.2, or ##STR49## wherein R.sub.3 is hydrogen, alkyl, substituted alkyl, or aryl, and R.sub.4 is alkyl wherein the term alkyl refers to both straight and branched chain groups having one to ten carbon atoms;

• the term substituted alkyl refers to alkyl groups having one or more substituents wherein the substituent is halogen, amino, azido, hydroxy, cyano, trialkylammonium (wherein each alkyl group has 1 to 6 carbons), alkoxy of 1 to 6 carbons, aryl and carboxy;
• the term aryl refers to phenyl and phenyl substituted with one, two or three substituents wherein the substituent is alkyl of 1 to 6 carbons, alkoxy of 1 to 6 carbons, halogen, trifluoromethyl, amino, alkylamino, dialkylamino, nitro, cyano, alkanoyloxy of 2 to 11 carbons, carboxy, carbamoyl and hydroxy.