Beiträge zur Chemie der Pyrrolpigmente, 77. Mitt. Synthese und Struktur vonb-Nor-bilatrienen-abc undb-Nor-biladienen-ac bzw. Bi-9,9′-dipyrrinonylidenen und Bi-9,9′-dipyrrinonylenen

B-Nor-biladienes-ac are prepared by oxidative coupling of dipyrrinones in nearly quantitative yields. Further oxidation of these derivatives yieldsb-nor-bilatrienes-abc. Constitutions, tautomerism, configurations at exocyclic double bonds, and conformations at exocyclic chromophore single bonds are determined for the crystalline state and their states of solution using X-ray structural analysis and spectroscopic methods, respectively.B-nor-biladienes-ac are found to be of (4Z,15Z)5sp,9sc,14sp geometry,b-nor-bilatrienes-abc are planar systems of (4Z,9E,15Z) configuration in the crystal, whereas in solutions there are indications of a more twisted conformation at their exocyclic chromophore single bonds.

Herr Dipl.-Ing.Heinz Flödl hat uns am 11. April 1988 für immer verlassen — wir trauern um ihn.