Description: Cefoxitin contains the same C-7 side chain as cephalothin and the same C-3 side chain as cefuroxime. The most novel chemical feature of cefoxitin is the possession of an-oriented methoxyl group in place of the normal H-atom at C-7. This increased steric bulk conveys very significant stability against -lactamases. The inspiration for these functional groups was provided by the discovery of the naturally occurring antibiotic cephamycin C derived from fermentation of Streptomyces lactamdurans. Cephamycin C itself has not seen clinical use but, rather, has provided the structural clue that led to useful agents such as cefoxitin. Agents that contain this 7 methoxy group are commonly referred to as cephamycins. Ingenious chemical transformations now enable synthetic introduction of such a methoxy group into cephalosporins lacking this feature.