Compounds represented by the formula 1: ##STR00001## A is selected from the group consisting of ##STR00002## wherein each R individually is H or acyl, Y is X, N.sub.3, NH.sub.2, monoalkylamino, or dialkylamino; Z is O or S; and X is selected from the group consisting of hydrogen, halo, hydroxy, alkoxy, alkyl, haloalkyl, alkenyl, haloalkenyl, alkynyl, amino, monoalkylamino, dialkylamino, thioaryl, thioalkyl, allylamino, cyano and nitro; tautomers thereof; and pharmaceutically acceptable salts thereof are provided along with methods for their fabrication. Various of these compounds can be used as anticancer agents, or antiviral agents or to inhibit DNA replication.