Photochemical Oxidations

Also iron(II) bearing minerals such as pyrite may be oxidized photochemically in the absence of oxygen according to the following reaction scheme (Jaegermann and Tributsch, 1988) ... 

Foley S, Crowley C, Smaihi M, Bonfils C, Erlanger BF, Seta P, Larroque C (2002) Cellular localisation of a water-soluble fullerene derivative. Biochem Biophys Res Commun 294 116-119. Foote CS (1991) Definition of Type-I and Type-II photosensitized oxidation. Photochem Photobiol 54 659-659. 

H-3,l-Benzoxazines and -benzothiazines can be made by the cyclization of benzyl alcohols thus, the benzoxazine (176) is obtained by the oxidative photochemical ring closure of the pyrrole derivative (175) (78JOC3415). The amides (177) and (179) can be cyclized to benzothiazines (178) with phosphorus pentasulfide or pentachloride respectively (1894CB3509). 

Moreover, there is considerable evidence that PPO is not active as a phenol oxidase in chloroplasts, but is limited as a phenol oxidase by latency or lack of substrate [18]. The latent form of the enzyme can be activated by a wide variety of treatments, including detergents [19], fatty acids [20] trypsin [21] and Ca2+ [22]. The results of Tolbert [21] indicated that light could activate latent PPO because polyphenols can be oxidized photochemically by chloroplast membranes in the absence of other... 

Foote CS (1991) Definition of type-I and type-II photosensitized oxidation. Photochem Photobiol 54 659-659... 

Aggregation of metallotriazole hemiporphyrazines possessing crown ethers was induced by alkali cations [95CC419] and the first examples of 2,2 -tethered bifluorenylidene crown ethers were synthesized using an oxidative photochemical cyclization process [95JOC7380]. 

Oxidative photochemical coupling of the anil (116) gives 3,4 7,8-dibenzophenanthridine (117),158 the structure of which was confirmed (as shown) by an independent synthesis from l,2 7,8-dibenzofluoren-one oxime (118).158... 

E. Ochiai, Aromatic Amine Oxides. Am. Elsevier, New York, 1967. V-Oxides, photochemical reactions of aromatic amine ... 

Corunnine, Nandazurine, ( )-Caaverine, ( )-Isoboldine, ( )-Thalicmi-dine, and ( )-Domesticine. Relative to the aporphine synthesis by enamide photocyclization, Kupchan and O Brien (141) have developed the oxidative photochemical synthesis of aporphine alkaloids. 

C(6>-acetylation, 184 bromination, 184 chlorinatiou, 184 chloromethylation, 184 dehydrogenation, xSg deuteration, 183 huorination, 184 formylation (Vdsmeier), 184 methylation, 184 oxidation (peroxy-acid), 184 oxidation (photochemical), 447 photolysis, 431... 

The study of the kinetics of oxidation (photochemical oxidation in particular) of aldehydes in liquid phase by dissolved oxygen has generally been carried out by measuring, as a function of time, the volume of oxygen absorbed at constant pressure. In experiments of this kind, the rate of dissolution of oxygen is governed by the chemical phenomenon and not by a physical phenomenon of diffusion, provided the two following conditions are fulfilled simultaneously (cf. references 5a and 5b) ... 

Slow oxidation of gaseous methanol. INIany authors have studied the slow oxidation, photochemical or thermal, of gaseous formaldehyde. This reaction is much more complex than that of the acetic or propionic aldehydes the peracid (performic acid) no longer constitutes the principal product of the reaction, and this reaction implies the occurrence of heterogeneous processes (on the vessel walls). It follows (cf. references 2 and 45-47) that this complex oxidation cannot be represented by so simple a mechanism as that which has previously been discussed with regard to other aldehydes. 

Bolland, Gee, et al. (cf. reference 48) to interpret the oxidation (photochemical, induced, or thermal) of ethylenic hydrocarbons in solution ... 

Debiais, Niclause, Horstmann, and Letort to represent the oxidation (photochemical or induced) of dibenzyl ether in liquid phase ... 

Total Organic Carbon (TOC) Combustion catalytic oxidation, combustion oxidation, photochemical oxidation, ozonation oxidation... 

Photochemical oxidants Photochemically produced oxidizing agents capable of causing damage to plants and animals. 

Chemical Stability Chemical degradation of the drug includes reactions such as hydrolysis, dehydration, oxidation, photochemical degradation, or reaction with excipients. The constant presence of water and oxygen in our environment means that exposure to moisture or oxygen can affect the chemical stability of a compound. Chemical stability is very important, not only because a sufficient amount of the dmg is needed at the time of administration for therapeutic purposes, but also because chemical degradation products may adversely affect the properties of the formulated product and may even be toxic. 

Several of the condensations with aromatic aldehydes have been used in the synthesis of alkaloid systems. 2-Nitrobenzaldehydes have been used in synthetic routes to 7-hydroxyaporphines/°° and 2-iodobenzaldehydes have been used in oxidative photochemical routes to the aporphines and oxoapor-phines caaverine, isoboldine, corunnine, and nandazurine. ° The aldehyde 46 has been used with the anion of the Reissert compound derived from... 

C.S. Foote (1991). Definition of Type I and Type II photosensitized oxidation. Photochem. PhotobioL, 54,659. 

Polypyrroles (PPy s) are formed by the oxidation of pyrrole or substituted pyrrole monomers. In the vast majority of cases, these oxidations have been carried out by either (1) electropolymerization at a conductive substrate (electrode) through the application of an external potential or (2) chemical polymerization in solution by the use of a chemical oxidant. Photochemically initiated and enzyme-catalyzed polymerization routes have also been described but are less developed. These various approaches produce polypyrrole (PPy) materials with different forms—chemical oxidations generally produce powders, whereas electrochemical synthesis leads to films deposited on the working electrode, and enzymatic polymerization gives aqueous dispersions. The conducting polymer products also possess different chemical/electrical properties. These alternative routes to PPy s are therefore discussed separately in this chapter. 

Hall, R.D., Buettner, G.R., and Chignell, C.F. (1991) The biphotonic photoionization of chlorpromazine during conventional flash photolysis spin trapping results with 5,5-dimethyl-1 -pyrrol inc-W-oxide, Photochem. Photobiol., 54, 167-173. 

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