- Controlled C-5 methylation of caffeine by benzoyloxy radical addition at C-8
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C-5 methylation of the model purine compound caffeine by acetyl benzoyl peroxide is the result of preferential addition of the electrophilic benzoyloxy radical at C-8 in neutral medium.X-ray structure and molecular orbital calculations on 1,3,5,7-tetramethyl-5,7-dihydrouric acid are presented.
- Zylber, J.,Ouazzani-Chahdi, L.,Chiaroni, A.,Riche, C.
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- Functionalization including fluorination of nitrogen-containing compounds using electrochemical oxidation
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Nitrogen-containing compounds have been subjected to electrochemical oxidation with Et3N-3HF as an electrolyte. Caffeine afforded 8- fluorocaffeine as a sole product in 40.3% yield. Guanosine tetraacetate and uridine triacetate gave the fluorinated compounds in 17.5 and 4.6% yields, respectively. Similar electrochemical oxidation of caffeine with methanol, KCl, or KCN afforded 8-methoxycaffeine, 8-chlorocaffeine, or 8- cyanocaffeine, respectively.
- Sono, Masakazu,Toyoda, Naoko,Shimizu, Kahori,Noda, Eiji,Shizuri, Yoshikazu,Tori, Motoo
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p. 1141 - 1145
(2007/10/03)
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- Functionalization Including Fluorination of Caffeine, Guanosine Tetraacetate, and Uridine Triacetate using Electrochemical Oxidation
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The title compounds have been subjected to electrochemical oxidation with Et3N-3HF as an electrolyte.Caffeine afforded 8-fluorocaffeine as a sole product in 43percent yield.Guanosine tetraacetate and uridine triacetate gave the fluorinated compounds in 7.3 and 4.8 percent yield, respectively.Similar electrochemical oxidation of caffeine with methanol, KCl or KCN yielded 8-methoxycaffeine, 8-chlorocaffeine, or 8-cyanocaffeine, respecticvely.
- Sono, Masakazu,Toyoda, Naoko,Shizuri, Yoshikazu,Tori, Motoo
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p. 9237 - 9238
(2007/10/02)
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- ADDITION OF ELECTROPHILIC RADICALS TO CAFFEINE: SYNTHETIC ASPECTS AND INFLUENCE OF THE PEROXIDIC INITIATORS
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Primary and secondary electrophilic radicals such as: .CHRCO2CH3 (R=H, CH3, CO2CH3) and tertiary .CCl3 radical were added directly at C-8 of, th model purine compound, caffeine to give the corresponding 8-substituted derivatives in fairly good yields.Unexpected reaction of caffeine with oxy radicals from the initiators (PhCO2., t-BuOO.) gave rise to C-5 substituted 1,3,7-trimethyl-5,7-dihydrouric acid derivatives (C-5-R=CCl3, CH3, C(CH3)2CO2CH3) and to the spirodihydantoin C-8 adduct derivative of caffeine 11.
- Zylber, J.,Ouazzani-Chahdi, L.,Lefort, D.,Chiaroni, A.,Riche, C.
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p. 721 - 732
(2007/10/02)
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- Nitro derivatives of bi- and tri-cyclic heterocycles as potential radiosensitizers
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Two series of bicyclic compounds having a pyridinic and pyrrolic nitrogen atom in different rings have been synthesized as potential radiosensitizers of hypoxic mammalian cells.The compounds were obtained from 3-nitropyrrolopyridine by regioselective alkylation at the nitrogen atom in either the 5- or 6-membered rings.Partition coefficients, one electron reduction potentials, radiosensitization of Chinese hamster V79 cells and cytotoxicity were measured.Generally, the N-1 alkyl-substituted 3-nitropyrrolopyridines showed greater electron affinity than their N-7 alkyl-substituted analogues.All compounds were substantially less electron affinic than the 2-nitroimidazole, misonidazole.Consistent with this, misonidazole showed the most efficient sensitizing properties.None of the compounds synthesized here showed significantly lower toxicity than misonidazole.Consequently there is likely to be no therapeutic benefit from using these novel compounds as radiosensitizers. - 1-alkyl-3-nitro-1H-pyrrolopyridine preparation and radiosensitizer activity/7-alkyl-3-nitro-7H-pyrrolopyridine, preparation and redox properties/3-nitro-1H-pyrrolopyrazine/radiosensitization/cytotoxicity
- Yizun, Jin,Adams, Gerald E.,Parrick, John,Stratford, Ian J.
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p. 511 - 516
(2007/10/02)
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