Nitrones and oxaziridines. XV. Approaches to 3-Oxo-1-pyrroline 1-Oxides by oxidation of 1-Pyrroline 1-Oxides

5,5-Dimethyl-1-pyrroline 1-oxide can be converted either by selenium dioxide or 3-methylbutylnitrite into the related 3-oxo compound, but the reaction is not general for other nitrones. Three 3-ethoxycarbonyl- 1-pyrroline 1-oxides have been prepared by base-catalysed acylation of simple pyrroline oxides, and nitrosation of one of these compounds results in the formation of a 3-oxo-pyrroline. The peracid oxidation of this oxopyrroline affords an oxazinone, the product of ring expansion.