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Oxidation photosensitized

Completely different results from those obtained in the photooxidation of 2.4.6-tri-tert-butyl-X phosphorin 24 (p. 54) are obtained in the photooxidation of 1.1-dimethoxy-2.4.6-tri-tert-butyl-X -phosphorin 183, as Schaffer has found. In this case the 2-hydroxy-endoxy-phosphinic acid methyl ester 213 can be isolated in about 20% yield. Its formation can be explained by assuming normal 1.4-addition to 212 as the primary product which is transformed to 213 by hydrolytic ring cleavage of the peroxide bridge, followed by loss of methanol. [Pg.126]


Cyclic 1,2,4-trioxanes (18 and 19) have been obtained from the photosensitized oxidation of fiirans (10,44,163). These compounds are... [Pg.118]

Imidazole rings also survive most oxidation conditions, but photosensitized oxidation of imidazoles can give diarylbenzamidines through a hydroperoxide (136) (70AHC(12)103). [Pg.60]

Photochemical synthesis of sulphoxides was reported for the first time by Foote and Peters111 in 1971. They found that dialkyl sulphides undergo smoothly dye-photosensitized oxidation to give sulphoxides (equation 32). This oxidation reaction has been postulated to proceed through an intermediate adduct 63, which could be a zwitterionic peroxide, a diradical or cyclic peroxide, which then reacts with a second molecule of sulphide to give the sulphoxide (equation 33). [Pg.251]

Depending on the relative concentration of reactive substrate and dissolved molecular oxygen ( 02), RF is able to induce photosensitized oxidation of molecular targets by either Type I (electron-transfer) or Type II (energy-transfer) processes (Foote, 1991). In Type I... [Pg.11]

Foote, C. S. (1991). Definition of Type I and Type II Photosensitized Oxidation. [Pg.21]

Lu, C. Lin, W. Wang, W. Han, Z. Yao, S. Lin, N. (2000). Riboflavin-(VB2) photosensitized oxidation of 2 -deoxyguanosine-5 -mono-phosphate (dGMP) in aqueous solution A transient intermediates study. Physical Chemistry Chemical Physics, Vol.2, 0anuary 2000), pp.329-334, ISSN 1463-9076. [Pg.22]

Foote, C., Photosensitized oxidation and singlet oxygen conseqnences in biological systems, in Free Radicals in Biology, Pryor, W.A., Ed., Academic Press, New York, 1976. [Pg.68]

Kndr, G. (2001) Intramolecular charge transfer excitation of meso-tetrakis (1-pyrenyl) porphyrinatogold(lll) acetate. Photosensitized oxidation of guanine. Inorganic Chemistry Communications,... [Pg.87]

In some studies it was shown that (3-carotene decomposes more rapidly than lutein and zeaxan-thin when exposed to oxidants or light in the presence and absence of rose bengal as a photosensitizer (Hurst et al., 2004 Ojima et al., 1993 Siems et al., 1999). However, it is not a rule, as lutein and zeaxanthin are depleted faster than (3-carotene during methylene blue photosensitized oxidation of human plasma (Ojima et al., 1993). [Pg.330]

Ojima, F, Sakamoto, H, Ishiguro, Y, and Terao, J, 1993. Consumption of carotenoids in photosensitized oxidation of human plasma and plasma low-density-lipoprotein. Free Radic Biol Med 15, 377-384. [Pg.348]

Wrona, M, Korytowski, W, Rozanowska, M, Sarna, T, and Truscott, TG, 2003. Cooperation of antioxidants in protection against photosensitized oxidation. Free Radic Biol Med 35, 1319-1329. [Pg.353]

At a molecular level, two mechanistic routes for photosensitized oxidation with dioxygen are usually recognized, termed type I and type II. [Pg.948]

The photosensitized results are from I.B.C. Matheson and J. Lee 118h It is seen that the quantum yields in photosensitized oxidation depend on the concentrations of luminol and base, and on temperature. At higher temperature (50°) and low luminol concentrations, the quantum yields reached those of hemin-catalyzed hydrogen peroxide oxidation of luminol in aqueous-alkaline solution. Primary products of the photosensitized oxidation are singlet oxygen (1Ag02) or a photoperoxide derived from methylene blue, but neither of these is directly responsible for the luminol chemiluminescence. [Pg.104]

Infusion solutions of pyridoxine (274) hydrochloride were unaffected by ward lighting, but when riboflavine phosphate sodium was added the pyridoxine was completely decomposed in about 3 h. The photosensitized oxidation gave... [Pg.96]

The three processes responsible for the transformation and degradation of disulfoton in water are abiotic hydrolysis, photosensitized oxidation, and biodegradation. Disulfoton is most stable towards... [Pg.148]

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. [Pg.102]

Greer A (2006) Christopher Foote s discovery of the role of singlet oxygen [102 (IDelta g)] in photosensitized oxidation reactions. Acc Chem Res 39 797-804. [Pg.103]

A method for synthesis of ozonides that involves no ozone has been reported. It consists of photosensitized oxidation of solutions of diazo compounds and aldehydes. Suggest a mechanism. [Pg.813]


See other pages where Oxidation photosensitized is mentioned: [Pg.136]    [Pg.35]    [Pg.35]    [Pg.27]    [Pg.1154]    [Pg.219]    [Pg.284]    [Pg.334]    [Pg.973]    [Pg.266]    [Pg.268]    [Pg.144]    [Pg.149]    [Pg.293]    [Pg.1579]    [Pg.1583]    [Pg.1593]    [Pg.204]    [Pg.616]    [Pg.673]    [Pg.676]    [Pg.691]    [Pg.692]    [Pg.694]    [Pg.732]    [Pg.947]    [Pg.949]    [Pg.1450]    [Pg.1477]    [Pg.1483]    [Pg.1485]    [Pg.162]   
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