Irradiation Isolation

The increase in levels of tissue CAT is compatible with previous results which showed that LLLT induced an increase in CAT activity of irradiated isolated cardio-myocytes compared to controls. It was suggested that laser therapy efficacy in chronic wounds and ulcers can be attributed to the activation of CAT in tissue fluids [62]. He-Ne laser has been shown to cause photoactivation and structural modifications of catalase enzymes that positively correlated with its functional properties in cell free system [63]. 

Figure 2 compares the distribution of components in a nonirradiated isolate (0°C.) with an irradiated isolate. The solid curve resulted when the beef had been irradiated at the cobalt-60 source and then distilled. The dashed curve shows separation of concurrently processed isolates. Figure 3 illustrates the decrease in volatile constituents brought about by storage. 

The nonirradiated isolates contained about equal amounts of 1-hexanal (22.86%) and a mixture of 1-octanal and acetoin (22.90%). Alcohols accounted for 32.25%. The irradiated isolates were similar, in that they contained about the same proportion of methional, but differed greatly in overall composition. The concurrently irradiated and distilled concentrates contained 55.24% aldehydes, 16.58% alcohols, and 3.67% hydrocarbons. The nonconcurrent isolates, on the other hand, contained 23.36% aldehydes, 18.30% alcohols, and 24.04% hydrocarbons. 

Bellon S, Ravanat J-L, Gasparutto D, Cadet J (2002) Cross-linked thymine-purine base tandem lesions synthesis, characterization, and measurement in y-irradiated isolated DNA. Chem Res Toxicol 15 598-606... 

After the reactions with 2-ethynylaniline la, paraformaldehyde (2 equiv), and secondary amine 2a (1.1 equiv) was completed on TLC, additives were introduced MW microwave irradiation Isolated yields... 

All reactions were conducted with ethynylaniline 1, paraformaldehyde (2 equiv), and secondary amine 2 (1.1 equiv) in the presence of Cul (2.5 mol%) in 1,4-dioxane at 170 °C for 20-40 min under microwave irradiation. After the indole ftnmation was completed (monitored by TLC), MeONa (6 equiv) was added and the mixture was heated at 170 °C for 20 min under microwave irradiation Isolated yields... 

The irradiation of tetra-/-butylcyclopentadienone with 254 nm light at 77 K produced a tricyclopentanone which, upon extended irradiation, lost carbon monoxide. Tetra-f-butyltetrahedrane was formed. This derivative of the second fundamental hydrocarbon of molecular formula (CH), namely tetrahedrane, is stable at room temperature and could be isolated after chromatography on silica gel in crystalline form (G. Maier, 1978). 

The 4-hydroxy-THISs react with electron-deficient alkynes to give cycloadducts (3) that spontaneously eliminate sulfur, producing 2-pyridones (3). Bulky 5-substituents lead to a decrease in the addition rate, and elimination of isocyanate with formation of thiophenes becomes favored (3, 12, 13). Benzyne yields an isolable adduct that exclusively extrudes isocyanate on thermolysis, but sulfur on irradiation (Scheme 7)... 

Significant protection of mice by several polysaccharides other than glucan isolated from S. cerevisiae has been described (209). A 2.16-fold protection in the LD q q is observed for one modifier, MNZ, when given 15 min prior to irradiation. Glucan protects 2.25-fold in this same protocol. Many of these polysaccharides may act through activation of the complement system, rather than directiy on ceHs. 

Photodimers of IV-methylisoindole and isobenzofuran have been isolated [8+8] dimers are the major products. The [8 + 8] dimer (30) obtained by UV irradiation of an acetone solution of isobenzofuran at -60 °C has anti stereochemistry (78HCA444, 82CC1195). 

A radical pathway has been proposed to account for the isolation of (381)-(383) from the irradiation of the 3//-indazole (380) (73T1833). Results of sensitization and quenching experiments suggest that the reaction proceeds from the excited singlet state. 

The evidence obtained clearly indicates that the above photorearrangements proceed by a mechanism involving a nitrile ylide intermediate since cycloadducts could be isolated when the irradiations were carried out in the presence of trapping agents. Intramolecular cycloaddition of the nitrile ylide followed by a 1,3-sigmatropic hydrogen shift of the initially formed five-membered ring readily accounts for the formation of the final product. 

Azete, trisdimethylamino-isolation, 7, 278 Azetes, 7, 237-284, 278-284 benzo fused, 7, 278 benzodiazepine fused applications, 7, 284 fused ring, 7, 341-362 structure, 7, 360 2,3-naphtho fusion, 7, 278 reactivity, 7, 279 structure, 7, 278 synthesis, 7, 282-283 Azetidine, acylring expansion, 7, 241 synthesis, 7, 246 Azetidine, 3-acyl-irradiation, 7, 239 synthesis, 7, 246 Azetidine, N-acyl-synthesis, 7, 245 Azetidine, alkyl-synthesis, 7, 246 Azetidine, 3-alkylthio-synthesis, 7, 246 Azetidine, 3-amino-synthesis, 7, 246 Azetidine, N-amino-oxidation, 7, 241 synthesis, 7, 246 Azetidine, aryl-synthesis, 7, 246... 

The postulated intermediates of the reaction, the 5-haloamines, can be isolated when the irradiation is performed in trifluoroacetic acid. 

P -Bonding is obviously also the initiating step in the complex photoisomerization sequence of the stereoisomeric 1,5-dien-3-ones (162) and (163) in ethanol. After low conversions of the starting dienones, an isomer containing an analogous chromophoric system [(164) and (165), respectively] was found to build up temporarily in each case. On longer photolysis times, both compound pairs (162)/(164) and (163)/(165), are consumed, and the mixtures of the four diastereomers (166)-(169) were isolated from both runs. According to separate irradiation experiments with each of these products, (166) and (167) on one hand, and (168) and (169) on the other, are... 

By contrast, direct irradiation of 2,5-dimethylfuran gave 2,4-dimethylfuran as the only isolated product (68JA2720). 

In 1970, Hiraoka reported that 2-cyanopyrrole, irradiated in methanol with a low-pressure mercury arc for 20 h, gave a mixture of 3-cyanopyrrole and pyrrole-2-carbaldehyde [70JCS(CC)1306]. l-Methyl-2-cyanopyrrole (38) also gave this reaction (Scheme 15) [71JCS(CC)1610]. In this case, the author isolated the product of the isomerization 39, the product of the shift in C-2 of the IV-methy 1 group 40, and a third product that was assumed to be derived from the addition of methanol to the Dewar pyrrole 41. The reaction depends on the temperature used in fact, no reaction occurred when the reaction was performed at -68°C. This result is in agreement with the presence of a thermal-activated step [78JCS(CC)131]. More... 

The irradiation of the thiophene in gas phase yields ethylene, allene, methyl-acetylene, carbon disulfide, and vinylacetylene. No Dewar thiophene or cyclo-propene derivatives were isolated (69CJC2965). The irradiation in liquid phase gave the Dewar thiophene which can be trapped as a Diels-Alder adduct with furan (85JA723). The Dewar thiophene and cyclopropene-3-thiocarbaldehyde can be obtained by irradiation in argon matrices at 10 K (86JA1691). 

The irradiation of 2- and 3-cyanothiophene gave interesting results in agreement with the scheme described above (Scheme 19). The photoisomerization reaction involved only the excited singlet state and Dewar thiophenes were isolated when the reactions were carried out at -68°C and shown to be intermediates in the isomerization reactions [79JCS(CC)881 79JCS(CC)966]. 

Some data were obtained from the photochemical isomerization of amino-isoxazoles. 5-Aminoisoxazoles gave the corresponding azirine (Scheme 21) [70JCS(C)1825] when a4-carboethoxy-substituted derivative was used, no azirine was isolated and the oxazole was the only product obtained (Scheme 21) (72CB748). The azirine intermediate was not observed upon irradiating 3-amino derivatives [91H(32)1765]. 

The irradiation of 3-carbomethoxyisoxazole (47) gave the corresponding oxazole (48) in very low yields (5-8%) without the isolation of the corresponding azirine (Scheme 22) [71JCS(C)1196]. Also in this case calculations show that the energy of the triplet state allows the formation of the biradical intermediate and then of the azirine. However, the low yields of the conversion can be explained considering that the transformation of the biradical intermediate into the azirine is an endothermic reaction (Fig. 10) [99H(50)1115]. 

There has been new information on the products of photolysis of derivatives of compound 1. Low temperature irradiation of the ester 254 gives a ketene (93JACS8621) the isolation of an isomeric ketene from a 3-pyridyldiazo ester suggests the involvement of the open chain form 255. Photolysis of the 3-phenyl derivative 256 in the presence of cyclopentadiene gives exo and endo cyclopropanes and a dipyridylstilhene, suggesting the intermediacy of the carhene 257 (99JOC6635). 

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