A compound represented by Formula I, or a polymorph, ester, tautomer, enantiomer, pharmaceutically acceptable salt or prodrug thereof: ##STR00001## wherein: R.sup.1 is halogen, --OR.sup.1, --SR.sup.11 or lower alkyl; R.sup.2 is --NHR.sup.8; R.sup.3 is selected from the group consisting of hydrogen, halogen, --SR.sup.8, --OR.sup.8, --CN, --C(O)R.sup.9, --CO.sub.2H, --NO2, --NR.sup.8R.sup.10, lower alkyl, lower alkenyl, lower alkynyl, lower perhaloalkyl, aryl, heteroaryl, alicyclic and heterocyclic, all optionally substituted, wherein: the aryl, heteroaryl, alicyclic and heterocyclic groups are optionally mono-, bi- or tri-cyclic, R.sup.4 is --CHR.sup.12--, --C(O), --C(S), --S(O)--, or --SO.sub.2--; R.sup.5 is aryl, heteroaryl, alicyclic, or heterocyclic, wherein the aryl group is substituted with 3 to 5 substituents, the heteroaryl group is substituted with 2 to 5 substituents, the alicyclic group is substituted with 3 to 5 substituents, the heterocyclic group is substituted with 3 to 5 substituents.