Dimers of 5,15-dioxoporphodimethenes with direct links between methine bridge carbon atoms

1981 ◽  
Vol 103 (19) ◽  
pp. 5854-5861 ◽  
Author(s):  
Juergen Hinrich Fuhrhop ◽  
Ehrenfried Baumgartner ◽  
Hans Bauer
Keyword(s):  
Bridge Carbon

Methene bridge carbon atom elimination in oxidative heme degradation catalyzed by heme oxygenase and NADPH-cytochrome P-450 reductase

1984 ◽  
Vol 235 (2) ◽  
pp. 657-664 ◽  
Author(s):  
John C. Docherty ◽  
Gay D. Firneisz ◽  
Brent A. Schacter
Keyword(s):  
Carbon Atom ◽  
Heme Oxygenase ◽  
Nadph Cytochrome ◽  
Heme Degradation ◽  
Bridge Carbon ◽  
Cytochrome P 450

Theory of oxygenated polymers with bridge carbon atom. The electronic structure

1997 ◽  
Vol 85 (1-3) ◽  
pp. 1139-1140
Author(s):  
O.A. Ponomarev ◽  
E.S. Shikhovtseva
Keyword(s):  
Electronic Structure ◽  
Carbon Atom ◽  
Bridge Carbon

scholarly journals Stereospecific haem cleavage. A model for the formation of bile-pigment isomers in vivo and in vitro

1976 ◽  
Vol 159 (1) ◽  
pp. 23-27 ◽  
Author(s):  
S B Brown
Keyword(s):  
Oxygen Molecule ◽  
Model Systems ◽  
Ring Cleavage ◽  
Bile Pigment ◽  
New Approach ◽  
Reaction Specificity ◽  
Bridge Carbon ◽  
Haem Iron

A new approach is suggested for an explanation of sterospecific haem degradation to biliverdin and bilirubin. A model is proposed in which an oxygen molecule, bound to the haem iron atom, attacks a methene-bridge carbon atom in an intramolecular reaction. Specificity of macrocyclic ring cleavage is explained on the basis of the different accessibilities of the bound oxygen molecule to the four methene bridges. The consequences of these ideas are assessed in relation to coupled oxidation in model systems and to haem catabolism.

Substituent effects on the chemical shifts of the bridge protons of benzonorbornenes

1967 ◽  
Vol 45 (11) ◽  
pp. 1185-1193 ◽  
Author(s):  
Naoki Inamoto ◽  
Shozo Masuda ◽  
Kazuo Tori ◽  
Katsutoshi Aono ◽  
Hiroshi Tanida
Keyword(s):  
Benzene Ring ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Electron System ◽  
Electronic Interaction ◽  
Orbital System ◽  
Significant Difference ◽  
Bridge Carbon ◽  
Hammett Relationship ◽  
Good Agreement

The substituent effects on the chemical shifts of the C9 bridge protons in a series of 6-substituted benzonorbornenes and benzonorbornadienes, and on those of the C2 protons in 5-substituted 2-indanols, were investigated. They were linearly correlated with the modified Hammett relationship τR − τH = ρ (σm + σp)/2. The ρ values obtained from the anti-C9 protons in the bornenes and bornadienes were slightly but significantly larger than those from the corresponding syn protons, whereas no significant difference was observed between the ρ values obtained from syn-9-benzonorbornenols and the indanols. The larger ρanti values were explained in terms of a stereospecific electronic interaction between the π-electron system of the benzene ring and the orbital system of the bridge carbon. In addition, it was shown that the above modified Hammett relationship gives generally a good agreement with the substituent effects on the aliphatic constituents of benzocyclenes and analogous compounds.

scholarly journals Loss of haem from cytochrome P-450 caused by lipid peroxidation and 2-allyl-2-isoprophylacetamide. An abnormal pathway not involving production of carbon monoxide

1977 ◽  
Vol 168 (3) ◽  
pp. 417-422 ◽  
Author(s):  
F De Matteis ◽  
A H Gibbs ◽  
A Unseld
Keyword(s):  
Lipid Peroxidation ◽  
Carbon Monoxide ◽  
Significant Extent ◽  
Haem Oxygenase ◽  
Bridge Carbon ◽  
Cytochrome P 450

1. Microsomal preparations undergoing lipid peroxidation produce CO and lose haem from cytochrome P-450. 2. The amount of CO produced does not correlate with the amount of haem lost and, after pre-labelling of microsomal haem in its bridges with 5-amino[5-14C]laevulinate, the radioactivity lost from haem is not recorved as CO. 3. Similarly, when pre-labelled microsomal haem is destroyed by the action of 2-allyl-2-isopropylacetamide, no radioactivity is recovered as CO. In clear contrast, on degradation of haem by the haem oxygenase system, CO is produced in an amount equimolar to the haem lost. 4. It is concluded that (a) the CO produced during lipid peroxidation originates from a source different from haem and (b) the degradations of haem caused by lipid peroxidation and 2-allyl-2-isopropylacetamide do not involve to any significant extent evolution of the methene-bridge carbon of haem as CO.

Conductivity of oxygenated polymers with bridge carbon atom in external a-c field. Consideration of the dissipation

1997 ◽  
Vol 85 (1-3) ◽  
pp. 1103-1104 ◽  
Author(s):  
E.S. Shiichovtseva ◽  
O.A. Ponomarev
Keyword(s):  
Carbon Atom ◽  
Bridge Carbon

BIOSYNTHETIC INCORPORATION OF ONE-CARBON UNITS INTO BERBERINE AND HYDRASTINE

1965 ◽  
Vol 43 (1) ◽  
pp. 133-144 ◽  
Author(s):  
Ram Nath Gupta ◽  
Ian D. Spenser
Keyword(s):  
Hydrastis Canadensis ◽  
Methyl Group ◽  
Lactone Group ◽  
Bridge Carbon ◽  
Tracer Experiments

The utilization of one-carbon precursors in the biosynthesis of hydrastine and berberine was investigated by tracer experiments with plants of Hydrastis canadensis L. The lactone group of hydrastine and the bridge carbon of berberine are shown to be derived from the S-methyl group of methionine.

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