Additionally, the methylthiotetrazole side chain inhibits γ-carboxylation of glutamic acid; this can interfere with the actions of vitamin K.[citation needed] It has been described as a third-generation cephalosporin.

Next, displacement with propargyl alcohol in the presence of zinc chloride gives predominanntly the stereochemistry represented by diastereoisomer 3.

The side chain is protected as the phenylacetylamide; the triple bond is partially reduced with a 5% Pd-CaCO3 (Lindlar catalyst) and then epoxidized with mCPBA to give 4.

Jones oxidation followed in turn by ozonolysis (reductive work-up with zinc-AcOH) and reaction with SOCl2 and pyridine give halide 6.

Next a sequence is undertaken of side chain exchange and introduction of a 7-methoxyl group analogous to that which is present in cephamycins and gives them the enhanced beta-lactamase stability.