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The formation of a 2-oxo-azetidine from N-phenyl-N-chloroacetyl-4-fluoro-phenacylamine, and 3-oxo-morpholines from corresponding 4-bromo-derivatives 2 indicates the possibility of the existence of dπ-acceptor resonance between the aromatic ring and the bromo-substituent. H-NMR studies of some morpholines reported earlier 3 indicate a planar heterocyclic structure with a rapidly inverting N₋aryl substituent. Where the rotation of the N-aryl group is strongly hindered 16, the C2 methylene protons show a geminai coupling of -14.5 Hz4. The 2-oxo-azetidine (4) shows an ABX coupling pattern for its ring protons. Preliminary work attempting to extend the synthesis of morpholines to azepines has resulted instead in the formation of a pyrrolidone.

Two new derivatives of the 1,4-oxazine ring system (3a and 3b) derived from p-aminobenz-amides have been synthesized. The uv absorption spectra of sixteen representative 1,4-oxazines all show two high intensity bands (ϵ ∼ 105) between 220-400 ran. The positions and intensities of the absorption maxima have been correlated with the steric and electronic effects of the oxazine ring substituents.

The preparation and antimicrobial activity of a series of beta-lactams (3a-f) are described. These compounds were prepared from the 2+2 cycloaddition of beta,beta-disubstituted enamines with aryl isocyanates; compounds 3a-f underwent facile beta-lactam ring fission between aminal carbon atom C4 and the lactam nitrogen N1. The resisting formylacetanilide derivatives were devoid of antibiotic activity.

The preparation and antimicrobial activity of a series of beta-lactams (3a-f) are described. These compounds were prepared from the 2+2 cycloaddition of beta,beta-disubstituted enamines with aryl isocyanates; compounds 3a-f underwent facile beta-lactam ring fission between aminal carbon atom C4 and the lactam nitrogen N1. The resisting formylacetanilide derivatives were devoid of antibiotic activity.