Metal-catalysed highly selective synthesis of α-amido-β-cyanoenaminones from acetoacetamides and cyanogen: physicochemical properties and solid-state conversion into pyrroline isomers

Abstract

Acetoacetamides add quantitatively to cyanogen in aprotic media at ambient conditions in the presence of [M(acac)₂](M = Cu or Ni; acac = acetylacetonate) complexes to give selectively 1 : 1 addition compounds. Products are amidic cyanoenaminones which can be converted thermally both in solution and in solid state into pyrrolinic cycloisomers. A variety of physicochemical methods including X-ray analysis, thermal analysis, ¹³C n.m.r. and ¹H n.m.r. has been employed for characterizing the new compounds and monitoring the isomerization reactions.