synthesis of ?-pyroneimine n-oxide a novel nitrone with electron releasing substituent

n-oxidation of 1,4-dihydro-2,6-dimethyl-1- phenyliminopyridine (7) with several peracids was attempted. the main compound obtained was l-phenyl- 2,6-dimethyl-4-pyridone (8), instead of the expected n-oxide (2). the reaction of phenylhydroxylamine with dimthylrnethoxypyroxonium perchlorate, however, successfully gave the n-oxide (3), which belongs to a class of nitrones in which the diazomethine n-oxide group is conjugated with an electron releasing center.