- A Study of the Favorskii Rearrangement with 3-Bromo-4-oxo-2,2,6,6-tetramethylpiperidin-1-oxyl
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Favorskii rearrangement reactions of the title compound with sodium hydroxide, sodium ethoxide, ammonia, several aliphatic amines, and ethyl sodiomalonate resulting in pyrrolidine nitroxyl radicals are described.
- Sosnovsky, George,Cai, Zhen-wei
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- A cyanine dye based supramolecular photosensitizer enabling visible-light-driven organic reaction in water
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We report the aggregation-induced photosensitizing activity of a cyanine dye in water and the mechanism. In addition, using the supramolecular assembly, visible-light-driven photooxidation of hydrophobic aromatic compounds in water was successfully performed. This journal is
- Fujitsuka, Mamoru,Kida, Toshiyuki,Mori, Tadashi,Ohkubo, Kei,Osakada, Yasuko,Shigemitsu, Hajime,Tamemoto, Tomoe
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supporting information
p. 11217 - 11220
(2021/11/09)
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- EPR detection of cellular and mitochondrial superoxide using cyclic hydroxylamines
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Superoxide (O2) has been implicated in the pathogenesis of many human diseases, but detection of the O2 radicals in biological systems is limited due to inefficiency of O2 spin trapping and lack of site-specific information. This work studied production of extracellular, intracellular and mitochondrial O2 in neutrophils, cultured endothelial cells and isolated mitochondria using a new set of cationic, anionic and neutral hydroxylamine spin probes with various lipophilicity and cell permeability. Cyclic hydroxylamines rapidly react with O2, producing stable nitroxides and allowing site-specific O2 detection in intracellular, extracellular and mitochondrial compartments. Negatively charged 1-hydroxy-4-phosphono-oxy-2,2,6,6-tetramethylpiperidine (PP-H) and positively charged 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl-trimethylammonium (CAT1-H) detected only extramitochondrial O2. Inhibition of EPR signal by SOD2 over-expression showed that mitochondria targeted mitoTEMPO-H detected intramitochondrial O2 both in isolated mitochondria and intact cells. Both 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CP-H) and 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CM-H) detected an increase in cytoplasm O2 stimulated by PMA, but only CM-H and mitoTEMPO-H showed an increase in rotenone-induced mitochondrial O2. These data show that a new set of hydroxylamine spin probes provide unique information about site-specific production of the O2 radical in extracellular or intracellular compartments, cytoplasm or mitochondria.
- Dikalov, Sergey I.,Kirilyuk, Igor A.,Voinov, Maxim,Grigor'Ev, Igor A.
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experimental part
p. 417 - 430
(2012/03/26)
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- Facile synthesis of 3-methoxycarbonyl-2,2,5,5-tetra-methylpyrrolidine-1-oxyl and derivatives
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We have achieved an efficient alternative synthesis of blood-brain-barrier permeable nitroxyl radicals 3-methoxycarbonyl-2,2,5,5-tetra-methylpyrrolidine-1-oxyl (1a) and 3-ethoxycarbonyl-2,2,5,5-tetramethylpyrroli-dine-1-oxyl (1b), which affords 1a and 1b in 65% isolated yields by four steps from 2,2,6.6-tetramethyl-4-piperidone (2), respectively. This protocol is applicable to the synthesis of 3-isopropoxy-2,2,5,5-tetramethylpyrrolidine-1-oxyl (1c) and 3-carbonyl-2,2,5,5-tetramethylpyrro-lidine-1-oxyl (6).
- Hatano, Bunpei,Araya, Hiroki,Yoshimura, Yutaka,Sato, Haruna,Ito, Tomohiro,Ogata, Tateaki,Kijima, Tatsuro
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experimental part
p. 349 - 356
(2010/09/05)
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