Even if a synthetic chemotherapeutic drug has few side effects, it does not implysuccess in clinical use. One mustrealize that chemotherapeutic agents usually are poisons, or at the very least,they are foreign to the body. Thedefence mechanism of the body, the reticuloendothelial system, recognizes themas such and tries to remove them as fast as possible. A fast excretion rate from the body oftenproves detrimental to chemotherapy. Cisplatin, for example, is eliminated from the body in a biphasicexcretion mechanism in such a way that 50% of the initial administered dose isexcreted within 20 hours . After 110hours, 70% of the initial administered amount of drug is removed from the bodyby the reticuloendothelial system. Theprinciple mode of excretion in mice appears primarily to be through the urine,90% of the injected dose being excreted within five days after injection. This quick excretion rate causes large drugconcentration fluctuations in the body, and hence, also unpredictabletherapeutic activity, a highly undesirable situation. The negative impact ofsuch drug concentration fluctuations in the body becomes apparent when onerelates it to 50% lethal dosages ( values), optimum dosages,and a dosage having no influence on the diseased site at all. For cisplatin , the dosage applicable to mice is 14mg/kg mass of test animal, the optimum doseis half of this, 7mg/kg test animal, but 3mg/kg mass of the test animalhas absolutely no influence on the diseased site at all. With the excretion profile that cisplatinshows, it is clear that it is extraordinary difficult to maintain drug levelsin a patient close to the optimum dose level, but still below the value for prolonged times. The initialrequired overdose of drug that is required to maintain useful drug levels inthe body explains muchof the negative side effects of chemotherapeutic drugs.
The mechanism for Pd(II) and Cu(II) porphyrin ring centred electrochemical hydrogen production was proposed consi-sting of a phlorin mediated pathway and a feasible explanation of ferrocene units role was suggested.
Investigating the Synthesis and Reactivity of Ferrocene
A novel nonphosphorus copolymer poly((3,3′-diphenyl diacetylethylenediamino)-1,1′-ferrocene) (PDPFDE) was synthesized, with the aim of reducing the fire hazards of epoxy resin (EP), via an aza-Michael addition reaction and was well characterized. A high char yield of about 62.9 wt % was obtained for PDPFDE from thermogravimetric analysis results, and a charring mechanism has been suggested that involves iron-cored carbon nanotubes as catalysts. An EP composite containing 5.0 wt % PDPFDE reached a low limiting oxygen index value of 29.1% and V-1 rating in the UL-94 test. On comparison with neat EP, the peak of the heat release rate and the total smoke production of the composite were reduced by 36.0% and 24.0%, respectively. Scanning electron microscopy and energy dispersive X-ray analysis results indicated the formation of coherent, dense, and nitrogen-rich char residues due to the incorporation of PDPFDE. Furthermore, the addition of an appropriate amount of PDPFDE improved the mechanical properties compared to pure EP.
What is the mechanism for the Friedel-Crafts acylation …
(2017)Ferrocene-Based Nonphosphorus Copolymer: Synthesis, High-Charring Mechanism, and Its Application in Fire Retardant Epoxy Resin. Industrial & Engineering Chemistry Research . ISSN 1520-5045
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Phosphoramidites that allow the generation of oligonucleotides containing site-specific lesions have been vital components for studying the mechanism of DNA repair. New DNA lesions are still being discovered and the study of their biological consequences will require their site-specific incorporation into oligonucleotides. The authors conclude that the increased availability of phosphoramidites for the synthesis of lesion-containing oligonucleotides should facilitate many future discoveries in the broad area of DNA damage and repair.
Ferrocene may be purified by ..
The general synthetic strategy towards water-soluble biodegradable drug carriers and the properties that they must have are discussed. The syntheses of water-soluble biodegradable copolymers of lysine and aspartic acid as potential drug-delivering devices, having amine-functionalised side chains are then described. Covalent anchoring of carboxylic acid derivatives of the antineoplastic ferrocene and photodynamically active phthalocyanine moieties to the amine-containing drug carrier copolymers under mild coupling conditions has been achieved utilising the coupling reagent O-benzotriazolyl-N,N,N′,N′-tetramethyluronium hexafluorophosphate to promote formation of the biodegradable amide bond. Even though the parent antineoplastic ferrocene and phthalocyanine derivatives are themselves insoluble in water at pH 7, the new carrier-drug conjugates that were obtained are well water-soluble.
319 | Peiwen Wu, Yang Yu, Claire E
The authors note that the detailed studies of the molecular mechanisms of DNA repair pathways were made possible by using site-specifically modified oligonucleotides and that the availability of phosphoramidites to synthesize oligonucleotides with DNA lesions has contributed to the field. They illustrate the article using primarily structural studies in the following examples: