Amines biological oxidation

Modeling the biological oxidation of tertiary amines, Audeh and Lindsay-Smith239 prepared perhydropyrido[l,2-a]pyrimidine by the oxidative cyclization of 3-piperidino propylamine by use of potassium hexacyano-ferrate(III) in potassium hydroxide solution. 

Symmetrical dinucleoside phosphoramidates and iV-substituted phosphora-midates (63) and (64) were obtained after oxidative coupling of the symmetrical //-phosphonate diester of AZT with the appropriate amine Biological evaluation on HIV-infected TK-deficient cell lines suggested that such dinucleoside phosphoramidates could not be regarded as pronucleotides, as they were unable to deliver the corresponding 5 -nucleotide inside the cells. 

Functionalization of SWCNTs and MWCNTs was shown to alter significantly the ability of these materials to induce oxidative stress. The addition of polyethylene glycol (PEG), sulfur (SH), or amine (NH2) groups reduced the biological oxidative damage, while it was slightly increased in the presence of carboxylic or hydroxide functionalization [14]. 

Riboflavin in its coenzyme forms (FMN and FAD) plays key metabolic roles in biological oxidation-reduction reactions involving carbohydrates, amino acids and lipids, and in energy production via the respiratory chain. These coenzymes also act in cellular metabolism of other water-soluble vitamins through the production and activation of folate and pyridoxine (vitamin Bg) to their respective coenzyme forms and in the synthesis of niacin (vitamin B3) from tryptophan. In addition, some neurotransmitters and other amines require FAD for their metabolism. Recently, Chocano-Bedoya et al. (2011) suggested a possible benefit of high intakes of riboflavin (about 2.5 mg/ day) from food sources on the reduction of incidence of premenstrual syndrome. 

Chlorination to residual chlorine content of a few tenths of a ppm is the usual treatment for control of biological growths in open recirculated systems. In order to discourage the development of chlorine-resistant strains, it is advisable to surprise the microbes at irregular intervals with other biocides (e.g., quaternary amines). Other oxidizing biocides (e.g., chlorine dioxide and ozone) used in municipal waters are normally too expensive for cooling water systems. 

Reactions. The chemistry of the /V-nitrosamines is extensive and will be only summarized here (8,35,42). Most of the reactions of the nitrosamines, with respect to thek biological or environmental behavior, involve one of two main reactive centers, either the nitroso group itself or the C—H bonds adjacent (a) to the amine nitrogen. The nitroso group can be removed readily by a reaction which is essentially the reverse of the nitrosation reaction, or by oxidation or reduction (68,69). 

A heterocyclic ring may be used in place of one of the benzene rings without loss of biologic activity. The first step in the synthesis of such an agent starts by Friedel-Crafts-like acylation rather than displacement. Thus, reaction of sulfenyl chloride, 222, with 2-aminothiazole (223) in the presence of acetic anhydride affords the sulfide, 224. The amine is then protected as the amide (225). Oxidation with hydrogen peroxide leads to the corresponding sulfone (226) hydrolysis followed by reduction of the nitro group then affords thiazosulfone (227). ... 

One of the biological pathways by which an amine is converted to a ketone involves two steps (1) oxidation of the amine by N.AD+ to give an imine, and (2) hydrolysis of the imine to give a ketone plus ammonia. Glutamate, for instance, is converted by this process into a-ketoglutarate. Show the structure of the imine intermediate, and propose mechanisms for both steps. 

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