The Park nucleotide is an important biological building block used in the construction of bacterial cell walls. Herein, we describe the synthesis of a radiolabeled Park nucleotide analog, p-iodophenoxyacyl-Ala-(D)-iso-Glu-Lys-(D)-Ala-(D)-Ala-OH-[I-125], using electrophilic destannylation. Anti-Park nucleotide antibody binding assays using a scintillation proximity assay (SPA) system showed good recognition of the radiolabeled surrogate. This methodology could be used for establishing a screen to identify inhibitors of peptidoglycan biosynthesis.

The synthesis of a series of 3-thiosubstituted carbacephem derivatives is described. The compounds were assayed against penicillin susceptible, intermediate and resistant strains of Streptococcus pneumoniae. Several analogs displayed potent in vitro activity against these organisms.