In recent years, the ability to prepare 4-substituted (3-lactams (2-azetidinones) has become a major synthetic objective. Monocyclic p-lactams bearing a heteroatom at C4 are of particular interest, especially as potential precursors of novel bicyclic p-lactams. The introduction of 4-alkyl groups into monobactams results in an increase in activity against Gramnegative bacteria and enhanced p-lactamase stability. Among a variety of methods for construction of the p-lactam ring, formation of the N-C4 bond is known to be a biomimetic process. Chemical syntheses of the 2-azetidinone ring by NC4 lactamisation mostly involve nucleophilic attack by N at C4, with displacement of a good leaving group, or intramolecular dehydration of p-hydroxy amide derivatives by application of the Mitsunobu reaction. Base-induced N-C4 cyclisation of azoacetates derived from pnitrophenylhydrazones of acetoacetanilides was envisaged as a potential route to novel 4-azo- 4-methyl-p-lactams. Lead (IV) acetate oxidation of acetoacetanilide p-nitrophenylhydrazones gave, in most cases, the expected azoacetates. With a-unsubstituted substrates, the usual intramolecular acétoxylation was not observed using acetic acid as solvent, and Z-azoalkenes were formed exclusively. a-Methyl derivatives afforded diastereomeric azoacetates in a stereoselective manner consistent with a Cram-type mechanism, as determined by X-ray crystallographic analysis. Mercury (II) acetate oxidation of a-unsubstituted acetoacetanilide p-nitrophenylhydrazones furnished the corresponding azoalkenes as mixtures of E- and Z-isomers. The configuration of each olefin was established through 1H NMR studies. Metallic acetate oxidation of toluene-p-sulfonylhydrazones derived from acetoacetanilides was perceived as a possible new synthesis of 4-methyl-2-azetidinones involving N-C4 cyclisation of a carbenic intermediate. Mercury (II) acetate oxidation of aunsubstituted substrates resulted in the unexpected formation of acetylenic amides. A system of model compounds was examined in order to gain insight into the reactivity of the acetoacetanilide-derived azoacetates and the conditions which might be employed to induce N-C4 dehydroacetoxylation. 1H NMR was used to determine the stereochemistry of model 3,4-dimethyl-2-azetidinones, where the trans-p-lactam was formed in preference to the cis-isomer. A variety of bases were identified which enable the conversion of acetoacetanilidederived azoacetates to novel 4-azo-4-methyl-2-azetidinones, The transformation is believed to involve an unstable Intermediate azoalcohol in some cases. The monocyclic 3-lactams prepared are important since they possess both an alkyl group and a heteroatom substituent in the 4-position.