Synthesis of 2H-1,3-oxazin-2-ones

Abstract

Treatment of C-substituted ternary maleisoimidium perchlorates (5), (18), and (24) with sodium azide gave the corresponding maleamic acid azides, which on heating underwent a Curtius rearrangement, followed by electrocyclisation, to yield 6-dialkylamino-derivatives of the novel 1,3-oxazin-2-one system. The action of sodium azide on maleisoimidium salts derived from secondary and tertiary maleamic acids resulted in the formation of the corresponding fumaramic acid azides.