Reactions of acetonedicarboxylic anhydride (tetrahydropyrantrione) and its mono- and di-acetyl derivatives with amines

Abstract

Acetonedicarboxylic acid reacts with acetic anhydride to give acetonedicarboxylic anhydride (I), its α-acetyl derivative (II), and its α,α′-diacetyl derivative (III). With aniline, compounds (I) and (II) reacted to give acetoacetanilide and 3,5-dioxo-4-carboxyhexanilide (IVb), respectively; compound (III) yielded the anils (IXa) and (Xa). Compound (IXa) isomerised in concentrated sulphuric acid to carboxyanilinodehydroacetic acid (XV) which resembles anilinodehydroacetic acid (XII) in several aspects. Compounds (IXa), (Xa), and (XV) underwent similar transannular rearrangements when heated.