Thermal decomposition of tert-butyl o-(phenoxy)- and o-(anilino)phenyliminoxyperacetates

Abstract

Some o-phenoxy- and o-anilino-substituted aryliminyl radicals have been generated by thermal decomposition of suitable tert-butyl iminoxyperacetates. The iminyls show no disposition to give 7-membered cyclisation on the phenyl group. In some cases, products have been found that can be rationalised through a 1,6-spirocyclisation of the iminyl radicals followed by homolytic 1,5-migration of the phenyl group from the aminic to the iminic nitrogen: this seems to be the first instance of such a process. Evidence has been found for the formation of imines through hydrogen abstraction by the iminyls; with two o-phenoxy-substituted peresters these imines have been unexpectedly isolated. The reactions have also afforded significant—in some cases major—amounts of other products (acridine, quinazolinone and indole derivatives) presumably deriving from carbon radicals: mechanisms are suggested to account for the formation of these compounds. The structure of the quinazolinone compound has been determined by X-ray crystallographic analysis.