Cyclic nitrones. II. Reactions of a cyclic α-keto nitrone with acetic anhydride, acetone, and methyl acetoacetate

Abstract

The cyclic α-keto nitrone 3,4,5,6-tetrahydro-5,5-dimethyl-3-oxopyridine 1-oxide (III) when treated with acetic anhydride and sulphuric acid gave in low yield a compound (XI) having both enol lactone and vinylogous amide functional groups. Hydrolysis and decarboxylation of compound (XI) with aqueous potassium hydroxide gave a vinylogous amide (V), also obtained by acid- or base-catalysed condensation of compound (III) with isopropenyl acetate or acetone. Base-catalysed condensation of (III) with methyl acetoacetate gave an ester (XVII) closely related to compound (V).