- N-Hydroxyphthalimide catalysts as bioactive pro-oxidants
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The catalytic role of N-hydroxyphthalimide (NHPI) in promoting free-radical hydrogen atom transfer (HAT) reactions, well-documented for processes of industrial and synthetic interest, is here investigated for the first time in a biological environment. While NHPI by itself did not show any bioactivity, selected NHPI-derivatives (NHPIDs) revealed the ability to activate the intracellular formation of reactive oxygen species (ROS), causing the depletion of glutathione (GSH) levels and an increase in oxidative stress (OS). The evident bioactivity of some of these derivatives resulted in a significant reduction of the viability in osteosarcoma MG-63, suggesting a new, potential role of NHPIDs as pro-oxidant drugs. The key role of the N-OH group in promoting oxidative stress is demonstrated.
- Melone,Tarsini,Candiani,Punta
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p. 21749 - 21755
(2016/03/08)
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- Sunlight induced oxidative photoactivation of N-hydroxyphthalimide mediated by naphthalene imides
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We report the aerobic photoactivation of N-hydroxyphthlimide (NHPI) to the phthalimido-N-oxyl (PINO) radical mediated by naphthalene monoimides (NI) for promoting the selective oxidation of alkylaromatics and allylic compounds to the corresponding hydroperoxides. In the absence of either NI or NHPI no oxidation was observed, meaning that the two molecules operate in a synergistic way. Sunlight as well as artificial UV-light irradiation was necessary in order to perform the process at low temperature (30-35 °C). EPR spectroscopy confirmed the role of NI and oxygen in promoting the formation of the superoxide radicals O2.- which, in turn, increased the concentration of PINO radicals during the UV light irradiation of NI/NHPI mixtures in MeCN. The investigation was extended to NI bearing different substituents on the naphthalene moiety. Finally, the synthesis and application of a unique photocatalyst including the NI and NHPI moieties linked by a suitable spacer was also considered. In this case the photocatalyst showed a substrate-dependent behaviour with some peculiarities in comparison to the system where NI and NHPI are independent units in the same reacting system. This photocatalytic system paves the way to a non-thermal, metal-free approach for C-H bond activation towards aerobic oxidation under very mild conditions. Copyright
- Melone, Lucio,Franchi, Paola,Lucarini, Marco,Punta, Carlo
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p. 3210 - 3220
(2013/12/04)
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- METHOD OF REGIOSELECTIVE SYNTHESIS OF SUBSTITUTED BENZOATES
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A method of synthesis of para-substituted benzoate esters and acids is provided, wherein the para-substituted regioisomer is obtained substantially free of the meta-substituted impurity, the method comprising contacting a coumalate ester or acid and an un activated alkene at elevated temperature in the presence of a metal oxidation catalyst and an oxidant. The metal oxidation catalyst can be palladium, such as palladium on carbon, and the oxidant can be the oxygen gas in ambient air. The reaction can be carlied out without solvent or in high boiling hydrocarbon solvents such as mesitylene. When the un activated alkene is a monosubstituted alkene, yields of at least about 50 or 60% of para-substituted ester and acid products, respectively, are obtained, substantially free of the regioisomelic meta-substituted impurity.
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Page/Page column 17
(2013/03/26)
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- NITROGENOUS FIVE-MEMBERED RING COMPOUNDS
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The present invention is to provide an aliphatic nitrogen-containing 5-membered ring compound represented by the formula [I] : wherein symbols in the formula have the following meanings;A: -CH2- or -S-,B: CH or N,R1: H, a lower alkyl group, etc.,X: a single bonding arm, -CO-, -Alk-CO-, -COCH2-, -Alk-O-, -O-CH2-, -SO2-, -S-, -COO-, -CON(R3)-, -Alk-CON(R3)-, -CON(R3)CH2-, -NHCH2-, etc.,R3: hydrogen atom or a lower alkyl group,Alk: a lower alkylene group, andR2: (1) a cyclic group which may be substituted, (2) a substituted amino group, etc., provided that when X is -CO-, then B is N, or a pharmaceutically acceptable salt thereof.
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- PHTHALIMIDE CARBOXYLIC ACID DERIVATIVES
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The present invention relates to phthalimide carboxylic acid derivatives of formula (I), methods for their preparation, pharmaceutical compositions containing them and their use in medicine, specifically in the treatment of cancer. (I), wherein X is O or S; R1 is a phthalimide carboxylic acid group of formula (II). R is hydrogen, C1-C6 alkyl, aryl or C1-C3 alkylaryl and R2, R3 and R4 represent various substituents.
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Page/Page column 67
(2008/06/13)
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