. . "o; Y is (CH2)1-3, or (CH2)1-3SO2, and Z is (??-(4-pyridyl)(C2???C4alkoxy), (??-((R8)(R9)amino)(C2???C4 alkoxy), an amino acid ester of (??-(HO)(C2???C4))alkoxy, N(R8)CH(R8)CO2H, 1???-D-glucuronyloxy, or OCH2CH2N(CH3)3 +; wherein R8 and R9 are each H, (C1???C3)alkyl or together with N, are a 5- or 6-membered heterocyclic ring having 1???3 N(R8), S or nonperoxide O; or Y-Z is (CH2)1-3R10 wherein R10" . .