Iron-based mediated process

In many respects the apparently analogous reduction of nitroarenes with triruthenium dodecacarbonyl under basic phase-transfer conditions is superior to that of the iron carbonyl-mediated reductions. However, the difference in the dependence of the two processes on the concentration of the aqueous sodium hydroxide and the pressure of the carbon monoxide suggests that they may proceed by different mechanisms. Although the iron-based system is most effective under dilute alkaline conditions in the absence of carbon monoxide, the use of 5M sodium hydroxide is critical for the ruthenium-based system, which also requires an atmosphere of carbon monoxide [11]. The ruthenium-based reduction has been extended to the... 

It should be emphasized that virmaUy all of the above discussion is based on biomimetic chemistry, where the Fe(II) source varies from salts such FeS04 to the more reactive FeCla-THaO as well as heme mimetics (TPP) and ester hematin variants. When heme models are used, since porphyrin alkylation is a favoured process, end-product distributions of products can be very different from when a free ferrous ion source is employed. Furthermore, solvent has been shown to have a profound effect on the rate of reaction and product distributions obtained in iron-mediated endoperoxide degradation. Thus all of these studies are truly only approximate models of the actual events within the malaria parasites. Future work is needed to correlate the results of biomimetic chemistry with the actual situation within the parasite. In general, most workers do accept the role of carbon-centred radicals in mediating the antimalarial activity of the endoperoxides, but the key information defining (a) the chemical mechanism by which these species alkylate proteins and (b) the basis for the high parasite selectivity remains to be unequivocally established. 

It is noteworthy that siroheme is present in the enzymes responsible for catalyzing two out of only three known six-electron processes, and accordingly it is of great interest to try and identify any feature in siroheme that makes it particularly suitable for the mediation of multielectron transfer. A comparison of octaethylporphyrin, octaethylchlorin and octaethylisobacteriochlorin complexes of iron shows that redox potentials and vco of Fe(P)L(CO) and Fe(P)L(CO)2 were nearly independent of the porphyrin. The property that was most dependent upon the macrocycle structure was the potential for ring-based oxidation which increased in the order OEiBC < OEC < OEP.734... 

BIOPLUME III is a public domain transport code that is based on the MOC (and, therefore, is 2-D). The code was developed to simulate the natural attenuation of a hydrocarbon contaminant under both aerobic and anaerobic conditions. Hydrocarbon degradation is assumed due to biologically mediated redox reactions, with the hydrocarbon as the electron donor, and oxygen, nitrate, ferric iron, sulfate, and carbon dioxide, sequentially, as the electron acceptors. Biodegradation kinetics can be modeled as either a first-order, instantaneous, or Monod process. Like the MOC upon which it is based, BIOPLUME III also models advection, dispersion, and linear equilibrium sorption [67]. 

ACD is a hypoprolrferative anemia that has traditionally been associated with infectious or inflammatory processes, tissue injury, or conditions associated with the release of proinflammatory cytokines. Alternative names include anemia of inflammation and cytokine-mediated anemia. The pathogenesis of the anemia of chronic disorders is based on three abnormalities shortened erythrocyte survival, impaired marrow response, and disturbance of iron metabolism. Pathologically, the RBCs have a shortened life span, and the bone marrow s capacity to respond to EPO is inadequate to maintain normal Hgb concentration. The cause of this defect is still uncertain, but appears to involve a block in the release of iron from the reticuloendothelial cells of the marrow. Various cytokines, such as interleukin-1, interferon-y, and tumor necrosis factor released during these illnesses may inhibit the production or action of EPO or the production of RBCs. ... 

The redox chemistry of the Prussian blue family (Table 7) has attracted considerable attention. The generation of thin films of Prussian blue has led to studies of its mediation in electron transfer reactions and of the electrochemical processes involved in its deposition and redox reactions. This work has been spurred by its electrochromic properties which have been used in prototype electronic display devices based, for example, on Prussian blue modified Sn02 electrodes. A recent review deals with the electrochemistry of electrodes modified by depositing thin films of PB and related compounds on them. Interestingly, true Prussian blue is somewhat difficult to process and modern iron blue pigments such as Milori blue are derived from the oxidation of rlin white Fe(NH4)2[Fe(CN)e] to give iron(III) ammonium ferrocyanides. 

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