Configuration and NMR study of tricyclic oxazines fused to a norbornene or norbornane skeleton

Abstract

Abstract Tricyclic oxazines fused with norbornane or norbornane were synthesized for pharmacological and stereochemical purposes. Analogous oxazin‐2‐ones and ‐2‐thiones were also obtained. The diendo or diexo anellation of the hetero ring to the norbornene or norbornane skeleton was confirmed by 1 H and 13 C spectral data. The assignment of the proton signals was proved and the proton‐proton coupling values were determined by double resonance experiments. With mono‐ and dichloroacetyl chloride, the oxazines fused to norbornene gave azetidinones which are mixtures of two isomers. The mixtures were separated into homogeneous substances, the configuration and conformation of which were determined via differential NOE experiments.