Compounds represented by the formula: ##STR00001## A is (CH.sub.2).sub.nR.sub.2, --CH.dbd.CH.sub.2, CH.sub.2--CH.dbd.CH.sub.2, O(CH.sub.2).sub.nR.sub.2, CH(OH)CH.sub.3, CH(OH)CH.sub.2OH, CH.sub.2--CH(OH)CH.sub.3, CH.sub.2CH(OH)CH.sub.2OH, or CH(OH)CH(OH)CH.sub.3, R,R.sub.1 individually is H, NH.sub.2OH, Cl, Br, I, aryl, substituted aryl, heterocycle, NR.sub.3R.sub.4, OR.sub.3 or SR.sub.3, R.sub.2 is H, OH, F, N.sub.3, NH.sub.2, CO.sub.2H, SH, alkyl, substituted alkyl, S-alkyl, O-acyl, CONH.sub.2, or CONH-alkyl, n is 1-3, y is O, S or NH, W is O or S, Z, Z' individually is OR.sub.3, OR.sub.4, O(CH.sub.2).sub.m--O--(CH.sub.2).sub.xCH.sub.3, NH--CH(alkyl)CO.sub.2R.sub.3, alkyl, substituted alkyl, OCH.sub.2CH.sub.2S--C(O)CH.sub.3, OCH.sub.2CH.sub.2S--C(O)CH(CH.sub.3).sub.2, OCH.sub.2CH.sub.2S--C(O)C(CH.sub.3).sub.3, OCH.sub.2CH.sub.2--SC(O)aryl, OCH.sub.2CH.sub.2--S--S--OCH.sub.2CH.sub.2OH, OCH.sub.2OC(O)C(CH.sub.3).sub.3, OCH.sub.2--O--C(O)OCH(CH.sub.3).sub.2, or OCH.sub.2--O--C(O)CH(CH.sub.3).sub.2 R.sub.3, R.sub.4 individually is H, alkyl, substituted alkyl, aryl, or substituted aryl;Both R.sub.3 and R.sub.4 can form a monocyclic ring of 4-7 atoms with N or optionally a further heteroatom in the ring; m is 1-3, x is 0-19; and pharmaceutically acceptable salts thereof and prodrugs thereof are provided.