Nitroimidazoles radiolysis

Several studies have reported the influence of nitroimidazole derivatives on biological systems. Thus the influence of Misonidazole, l-(2-nitro-l-imidazoyl)-3-methoxy-propan-2-ol, on strand breaking in calf thymus DNA under ionizing radiation conditions has been assessed70. Pulse-radiolysis studies of nitroheterocyclic compounds have examined... 

Whillans DW, Hunt JW (1978) Rapid-mixing studies of the mechanisms of chemical radiosensitization and protection in mammalian cells. Br J Cancer 37 38-41 Whillans DW, Hunt JW (1982) A rapid-mixing comparison of the mechanisms of radiosensitization by oxygen and misonidazole in CHO cells. Radiat Res 90 126-141 Whillans DW, Adams GE, Neta P (1975) Electron-affinic sensitization. VI. Pulse radiolysis and ESR comparison of some 2- and 5-nitroimidazoles. Radiat Res 62 407-421... 

The ESR spectra of radical ions of known radiosensitizers metronidazole, misonidazole, omidazole, and other nitroimidazoles have been investigated in the conditions of photolysis [856, 857], pulse radiolysis [849, 856, 858-865], and in the presence of other donors of free electrons [866-872], Radical anions of 2-nitroimi-dazole [849] and 4(5)-nitroimidazole [860] depending on medium pH can exist in three forms (Scheme 3.21) ... 

This dependence may be useful in search of potential radiosensitizers. Determined with the help of pulse radiolysis, the thermodynamic potentials of one-electron reduction of 2-, 4-, and 5-nitroimidazoles (pH 7) have a higher negative values than those obtained by classical polarography (pH 7.4) [946], Probably, it is generated by the fact that the process of electrochemical reduction involves irreversible stages of the decomposition of nitroimidazole anion radicals. The correlation of E (and E1/2) of nitroimidazoles and their radiosensitizing properties is discussed. With E7 values the correlation is found to be better [946],... 

The electron affinity of 2- and 5-nitroimidazoles calculated by a semiempirical quantum-mechanical method satisfactorily correlates with experimental values of one-electron reduction potentials measured by pulse radiolysis [942],... 

Pulse radiolysis has been used to measure the bimolecular rate constants of the electron transfer reaction for substituted 2- and 5-nitroimidazoles of interest as antiprotozoal drugs and radiosensitizers [951], The mechanism of inhibition of... 

P. Wardman and E.D. Clarke, One-electron reduction potentials of substituted nitroimidazoles measured by pulse radiolysis, J. Chem. Soc., Faraday Trans. 1, 72 (1976) 1377. 

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