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  • 1
    Electronic Resource
    Electronic Resource
    Reactivity of pyrrole pigments - Part 14. The electrochemical oxidation and reduction of bile pigments
    Amsterdam : Elsevier
    Bioelectrochemistry and Bioenergetics 29 (1992), S. 1-17 
    Details
    ISSN: 0302-4598
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0302-4598(92)80049-M
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The antioxidant role of bile pigments evaluated by chemical tests
    Amsterdam : Elsevier
    Bioorganic and Medicinal Chemistry 2 (1994), S. 181-185 
    Details
    ISSN: 0968-0896
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0968-0896(00)82013-1
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  • 3
    Electronic Resource
    Electronic Resource
    Reactivity of pyrrole pigments, part XVII. Reduction of bile pigments by sodium dithionite (1995)
    Springer
    Monatshefte für Chemie 126 (1995), S. 355-360 
    Details
    ISSN: 1434-4475
    Keywords: Bilirubin ; Biliverdin ; Urobilinogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Bilandione können auf einfache Art aus den entsprechenden alkylsubstituierten Bilin- order Biladien-ac-dionen durch Reduktion mit Natriumdithionit hergestellt werden. Durch Reduktion von vinylsubstituierten Dipyrrinonen mit Natriumdithionit erhält man die entsprechenden alkylsubstituierten 4,5-Dihydrodipyrrinone.
    Notes: Summary Bilanediones can be easily obtained by sodium dithionite reduction of the corresponding alkyl-substituted bilindiones or biladiene-ac-diones. By reduction of vinyl-substituted dipyrrinones with sodium dithionite, the corresponding alkyl-substituted 4,5-dihydrodipyrrinones can be obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00816105
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  • 4
    Electronic Resource
    Electronic Resource
    On the preparation of bilirubins of the natural α series substituted with a propionic acid residue and a hydroxypropyl group (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 85-89 
    Details
    ISSN: 1434-4475
    Keywords: Acylal ; Bile pigment ; Biliverdin ; Cyclic esters ; Selective reduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Reduktion von Mesobiliverdin-XIIIα-propan-1,3-diyl-diester mit NaBH4 liefert Mesobilirubin-XIIIα-propan-1,4-diyl-diester. Die analoge Reaktion des Mesobiliverdin-XIIIα-methylen-diesters führt zu 8-(2-Carboxyäthyl)-3,17-diäthyl-12-(3-hydroxypropyl)-2,7,13,17-tetramethylbiladien-ac-1,19-(21H,24H)-dion (MBR-mc).MBR-mc weist in Lösung (UV/Vis und 1H-NMR Spektren) eine ähnliche Struktur auf wie die der natürlichen Bilirubine der α-Serie.
    Notes: Summary The reduction of mesobiliverdin XIIIα propan-1,3-diyl diester with NaBH4 affords mesobilirubin XIIIα propan-1,3-diyl diester. The same reduction of mesobiliverdin XIIIα methylen diester. The same reduction of mesobiliverdin XIIIα methylen diester affords 8-(2-carboxyethyl)-3,17-diethyl-12-(3-hydroxypropyl)-2,7,13,17-tetramethylbiladien-ac-1,19-(21H, 24H)-dione (MBR-mc). The UV/Vis and1H NMR spectra ofMBR-mc show that its structure in solution is similar to that of the natural bilirubins of the α series.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807412
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  • 5
    Electronic Resource
    Electronic Resource
    Reactivity of pyrrole pigments, XXI: Structure and reactivity of Cu(II) and Zn(II) bilindione chelates (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 1051-1062 
    Details
    ISSN: 1434-4475
    Keywords: Bile pigments ; Transition metal bilindione chelates ; d-π Orbitals interaction ; Metalloporphyrin π cation radical ; Bilindione π neutral radical
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Einige Mn, Cu and Zn Chelate von Etiobiliverdin-IV-γ, Mesobiliverdin-IXα und seinem Dimethylester werden untersucht. Im Komplex koordiniert ein Metallatom (mit der Formalladung II) mit einem Neutralradikal des dreifach NH-deprotonierten Bilindions. Die Reaktivität des Komplexes gegenüber nukleophilen Lösungmitteln entspricht erwartungsgemäß dem eines neutralen π-Radikals; in CH3OH wird er zu Dimethoxybilipurpurin oxidiert. Bei Cu(II)-Etiobiliverdinat-IVγ beobachtet man im festen Zustand neben schwacher, antiferromagnetischer Kupplung zwischen d9Cu und π-Radikal (J=−23 cm−1) auch eine schwache, intermolekulare, antiferromagnetische Wechselwirkung zwischen zwei π-Radikalen (J=−45 cm−1). Dieses magnetische Verhalten wird dem des π-Kationradikals von Metalloporphyrinen gegenübergestellt.
    Notes: Summary Several Mn, Cu, and Zn chelates of etiobiliverdin-IV-γ, mesobiliverdin-IXα, and its dimethyl ester are studied. The results show that the chemical constitution of the Cu biliverdin chelate corresponds to a formal metal oxidation state of (II) coordinated to a neutral radical of the NH trideprotonated biliverdin. The reactivity of the Cu(II) bilindione chelates in nucleophilic solvents agrees with that expected for a π neutral radical structure of the ligand; in CH3OH, they undergo oxidation towards dimethoxybilipurpurins. The magnetic behaviour of Cu(II) etiobiliverdinate-IV-γ in the solid state shows an intramolecular weak antiferromagnetic coupling d9Cu-to-π-radical (J=−23 cm−1) and an intermolecular weak antiferromagnetic coupling π-radical-to-π-radical (J=−45 cm−1). The analogy of this magnetic behaviour to that of the π cation radical of metalloporphyrins is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807578
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  • 6
    Electronic Resource
    Electronic Resource
    Proton-induced dismutation of superoxide in aprotic media by bile pigments (1990)
    Springer
    Cellular and molecular life sciences 46 (1990), S. 63-67 
    Details
    ISSN: 1420-9071
    Keywords: Bile pigments ; bilirubin ; superoxide dismution ; superoxide scavenger
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclic voltammetry of molecular oxygen in aprotic media (dimethylformamide) and in the presence of bilirubin and other bile pigments shows that superoxide anion ( $$O_{\mathop 2\limits^. }^ - $$ ) undergoes proton-induced dismutation. Lactam hydrogens of bile pigments are sufficiently acid to induce $$O_{\mathop 2\limits^. }^ - $$ disproportionation to O2 and H2O2. Because of its characteristic lipophilic behavior, a biological role for natural bilirubin similar to that of other non-enzymatic lipophilic scavengers of $$O_{\mathop 2\limits^. }^ - $$ is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01955417
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  • 7
    Electronic Resource
    Electronic Resource
    Reactivity of pyrrole pigments, XIX. On the structure of Cu(II) and Zn(II) chelates of dipyrrins in solution (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 927-933 
    Details
    ISSN: 1434-4475
    Keywords: Coordination compounds ; Electrospray mass spectrometry ; Dipyrrins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Cu(II)- und Zn(II)-Chelate von 1,2,3,7,9-Pentamethyldipyrrin und 1,2,3,7,9-Pentadimethyl-8-sulfodipyrrin wurden untersucht. Bei Einsatz von Metalldiacetaten für die Komplexbildung wurden Dipyrrinmetallacetate als Vorläufer derbis-Dipyrrinate nachgewiesen.
    Notes: Summary The Cu(II) and Zn(II) chelates of 1,2,3,7,9-pentamethyldipyrrin and 1,2,3,7,9-pentamethyl-8-sulfodipyrrin are studied. When metal acetates are used for the formation of the metal complexes, dipyrrinate metal acetates could be detected as precursors of thebis-dipyrrinates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807032
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  • 8
    Electronic Resource
    Electronic Resource
    Reactivity of pyrrole pigments, XX. On the structure of Cu(II) and Zn(II) tripyrrin-1-one chelates in solution (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 935-946 
    Details
    ISSN: 1434-4475
    Keywords: Coordination compounds ; Bile pigments ; d-π Orbital interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Cu(II)- und Zn(II)-Chelate von 12,14-Dimethyl-2,3,7,8-tetraethyl-15H-tripyrrin-1-on, 12,13-Dimethyl-2,3,7,8-tetraethyl-15H-tripyrrin-1-on und ihrer Sulfonate wurden untersucht. Erwartungsgemäß findet man einen NH-dideprotonotierten Liganden im Chelat; im Zn-Complex von 12,14-Dimethyl-2,3,7,8-tetraethyl-15H-tripyrrin-1-on ist der Ligand nur einfach deprotoniert, und das Lactam ist zur Hydroximinogruppe tautomerisiert.
    Notes: Summary The Cu(II) and Zn(II) chelates of 12,14-dimethyl-2,3,7,8-tetraethyl-15H-tripyrrin-1-one, 12,13-dimethyl-2,3,7,8-tetraethyl-15H-tripyrrin-1-one, and their sulfonate derivatives are studied. The chelates show the expected structure of an NH dideprotonated ligand chelating the metal ion. However, in the case of the Zn chelate of 12,14-dimethyl-2,3,7,8-tetraethyl-15H-tripyrrin-1-one the ligand is only monodeprotonated, and the lactam ring is tautomerized to a hydroximino function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807033
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