Studies on the 1,4-Oxazepine Ring Formation Reaction Using the Molecular Orbital Method.

1,4-Oxazepine formation reactions of 1,8-naphthyridine derivatives (1-4) with peroxy acid have been studied using a semiempirical MO method (AM1) and an ab initio molecular orbital method (Gaussian 94). The energies of molecules involved in the reaction paths were calculated and the transition states related to experimental products were obtained. For the reactions of 1-3, the calculated energies of the transition states predicted the previously obtained products. However, the calculated values for the reaction of 4 suggested a different type of oxazepine compound, which was verified in further experiments.