The present invention is directed to compounds represented by the following structural formula, and pharmaceutically acceptable salts, solvates and hydrates thereof, R1 is selected from the group consisting of hydrogen, substituted or unsubstituted group selected from C1 C8 alkyl, aryl-C0-4-alkyl, heteroaryl-C0-4-alkyl, and C3 C6 cycloalkylaryl-C0-2-alkyl; W is O or S; X is an optionally substituted C1 C5 alkylene linker wherein one carbon atom of the linker may be replaced with O, NH or S; Y is C, O, S, NH or a single bond; E is C(R3)(R4)A or A ##STR00001##