The present invention is directed to compounds represented by the following structural formula, and pharmaceutically acceptable salts thereof, Formula I: wherein: (a) R5 is selected from the group consisting of (C.sub.1-C.sub.6) alkyl, (C.sub.1-C.sub.6) alkenyl, substituted aryl(C.sub.0-C.sub.4)alkyl, substituted aryloxy(C.sub.0-C.sub.4)alkyl, substituted arylthio(C.sub.0-C.sub.4)alkyl, unsubstituted aryl(C.sub.0-C.sub.4)alkyl, unsubstituted aryloxy(C.sub.0-C.sub.4)alkyl, and unsubstituted arylthio(C.sub.0-C.sub.4)alkyl; (b) T1 is C or N; (c) Q is selected from the group consisting of O, a single bond, O(CH.sub.2).sub.q and C; (d) q is 1 or 2; (e) W is selected from the group consisting of O, S, (CH.sub.2).sub.rN(R20)(CH.sub.2).sub.k, NHSO.sub.2, C(O)N(R20)(CH.sub.2).sub.r, (CH.sub.2).sub.rN(R20)C(O), and SO.sub.2; (f) X is C.sub.mH.sub.2m; (g) m is 0, 1 or 2; (h) A is an functional group selected from the group consisting of carboxyl, C1-C3 alkylnitrile, carboxamide, and (CH.sub.2).sub.nCOOR19; and (i) R19 is selected from the group consisting of hydrogen, optionally substituted C1-C4alkyl and optionally substituted arylmethyl.