Zur Reaktivität von C=N-Doppelbindungssystemen, XII¹ über Kupfer(II)- und Nickel(II)-Komplexe von Aminomethylen-1.3-dicarbonylverbindungen / The Reactivity of the C=N-Double Bond System, XII¹ Copper(II) and Nickel(II) Complexes of Aminomethylen-1,3-dicarbonyl Compounds

Abstract

Abstract Reaction of active methylene compounds (2,4-pentanedione, dimedone, 4-hydroxycoumarin, 4-hydroxycarbostyriles) with triethyl orthoformate and primary amines (aniline, o-methylmercapto aniline, cyclohexylamine) yields substituted aminomethylen-1.3-dicarbonyles (1-5), which in their tautomeric form (B) give stable, deeply coloured Cu··- and Ni- --organic complexes (6-27). The same chelates may also be obtained by direct reaction of orthoformate, amine and active methylene in the presence of the metal acetate at 40-50 °C in 65-90% yield. Anilinomethylene-3-methyl-1-phenylpyrazolone in turn does not exhibit any tendency to chelate Cu·· or Ni··. The X-ray crystallography of its o-methylmercaptoderivative shows it to exist in the virtually planar enamin form.