Reactivity of Pyrrole Pigments, Part 15: On the Oxidation of Bilirubins and Biliverdins

Article abstract of DOI:10.1007/BF00814136

Characteristic oxidation reactions of bilin-1,19-diones (biliverdins) and biladien-ac-1,19-diones (bilirubins) were reinvestigated.These include bromine and iodine oxidation of biliverdin IXα, bilirubin IXα and their Zn(II)complexes, the reaction described by Siedel (1941) of mesobilirubin XIIIα dimethyl ester with nitric acid (Gmelin reaction) and Smith's oxidation (1977) of etiobiliverdin IVγ using Tl triacetate and Pb tetra-acetate.For some of these reaction products new structures were assigned on the basis of their spectrometric data.These structures agreed with the expected reactivity pattern of biliverdins and bilirubins. Keywords: Bilipurpurins; Biliviolins; Electron transfer vs.Electrophilic attack.