18922-88-8Relevant academic research and scientific papers
Reactions of Iron Porphyrins with Methyl Radicals
Brault, D.,Neta, P.
, p. 2705 - 2710 (1981)
The reactions of methyl radicals with ferric, ferrous, and iron-free deuteroporphyrin have been investigated in neutral and alkaline water-2-propanol mixtures.Steady-state radiolysis of methyl chloride saturated solutions of ferric deuteroporphyrin, or ch
Porphyrin-linked nitroimidazole antibiotics targeting Porphyromonas gingivalis
Yap, Benjamin C.-M.,Simpkins, Grace L.,Collyer, Charles A.,Hunter, Neil,Crossley, Maxwell J.
, p. 2855 - 2863 (2009)
Periodontal disease is an inflammatory process affecting supporting tissues surrounding the teeth. The anaerobic Gram-negative bacterium Porphyromonas gingivalis is implicated in the disease. This organism requires the uptake of porphyrins most apparently as haem 1 from local haemorrhage and it has a HA2 receptor on the outer membrane for this purpose that provides the opportunity to achieve selective anti-microbial activity. Uniquely, this receptor is based on recognition of porphyrin macrocycle and on a propionic acid side-chain rather than recognition of the coordinated metal ion through chelation, a process used by other organisms with the HasA porphyrin receptor. Porphyrin-antibiotic conjugates 11, 12, 13a and 13b were designed as potential highly selective P. gingivalis inhibitors, a key point being that they are based on the use of free-base porphyrins to render them unpalatable to other organisms. These compounds were synthesised from metronidazole 4 and deuteroporphyrin IX 3. Conjugates 11, 12, 13a and 13b are all recognised by the HA2 receptor of P. gingivalis, bind as strongly as haem 1 to HA2 and are highly effective. For example, the amide-linked mono-metronidazole mono-acid adducts 11 and 12 have the same growth inhibitory activity towards P. gingivalis and both are two-fold more active than metronidazole 4 and ten- to twenty-fold more effective than the metronidazole derivative, amine 5. The methyl esters 9 and 10, in contrast, are not recognised by HA2 and are ineffective in inhibiting P. gingivalis, leading to the conclusion that capture by HA2 may be necessary for activity of the adducts. Preliminary growth inhibition assays involving a range of bacteria have demonstrated the high selectivity of conjugates 13a and 13b towards P. gingivalis.
One-Electron Reduction of Ferrideuteroporphyrin IX and Reaction of the Oxidized and Reduced Forms with Chlorinated Methyl Radicals
Brault, D.,Bizet, C.,Morliere, P.,Rougee, M.,Land, E. J.,et al.
, p. 1015 - 1020 (1980)
α-Hydroxyisopropyl radicals prepared by fast electron irradiation of aqueous solutions containing 2-propanol and acetone were found to reduce monomeric ferrideuteroporphyrin to ferrodeuteroporphyrin with a rate constant of 3.7*108 M-1 s-1.Relaxation of the coordination sphere is found to proceed with a rate constant k > 5*105 s-1.Irradiation of such solution in the added presence of various concentrations of CCl4, CHCl3, or CH2Cl2 enable studies to be made of the reactions of ferri- and ferrodeuteroporphyrin with chlorinated methyl radicals.No reaction of ferrideuterroporphyrin with CCl3 could be detected (k 6 M-1 s-1).For ferrrodeuteroporphyrin it appears that a rapid reaction (k = (2 +/- 1)*109 M-1 s-1) gives a complex (DPFeII-CH3-nCln) which undergoes further reaction as shown by transient spectral modifications.These results suggest that ferrous cytochrome P450 is likely to react rapidly with chlorinated radicals.A model for the toxicity and detoxification of CCl4 is proposed.
