Ferrocenyl-penicillin

Edwards El, Epton R, Marr G (1976) 1, l -Ferrocenyldiacetic acid anhydride and its use in the preparation of heteroannularly substituted ferrocenyl-penicillins and -cephalosporins. J Organomet Chem 122 C49-C53... 

Fig. 3 Organometallic complexes of known organic antiproliferation agents designed to overcome drug resistance a ferrocenyl-penicillin derivatives b ferrocenyl-cephalosporin derivatives c rhodium chloroquine complex d ferrocenjd-chloroquine derivative e iri-dium-COD-pentamidine complex...

When the ferrocenyl group is situated too dose sterically to the p-lactam nudeus, where R = FcC(O)-, no antibiotic activity is observed for the modified penicillins and cephalosporins. However, the addition of a methylene spacer to distance the ferrocenyl moiety from the p-lactam nudeus restores the antibiotic activity to the same high levd as that of the controls (Penicillin G and methidUin). Replacement of the methylene by CMe2 increases p-lactamase inhibition and decreases the antibiotic activity. For a recent and exhaustive review of metallic antibiotics in general, see Ming [10]. 

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