Experiments towards the synthesis of corrins. Part XII. Synthesis and some reactions of β-oxo-Δ1-pyrroline 1-oxides

Abstract

β-Oxo-Δ¹-pyrroline 1-oxides have been synthesised in two ways: (i) by oxidation of the corresponding γ-oxo-N-hydroxypyrrolidine formed by the base-catalysed aldol-type reaction of a nitrone and a methylene ketone, (ii) by the Claisen-type reaction of a 2-alkyl-Δ¹-pyrroline 1-oxide with a carboxylic ester. β-Oxo-nitrones can, in some cases, be reduced to the corresponding β-amino-αβ-unsaturated ketones, which are potential precursors of the AB component of the corrin ring system. Under oxidative conditions β-oxo-nitrones yield dimers in a manner similar to β-dinitrones.