- Characterization of the methemoglobin forming metabolites of benzocaine and lidocaine
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1.Topical anesthesia with benzocaine or lidocaine occasionally causes methemoglobinemia, an uncommon but potentially fatal disorder where the blood has a reduced ability to transport oxygen. Previous in vitro studies using human whole blood have shown tha
- Hartman, Neil,Zhou, Hongfei,Mao, Jinzhe,Mans, Daniel,Boyne, Michael,Patel, Vikram,Colatsky, Thomas
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- Oxidation of 2,6-dimethylaniline by recombinant human cytochrome P450s and human liver microsomes
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2,6-Dimethylaniline (2,6-DMA) is classified as a rodent nasal cavity carcinogen and a possible human carcinogen. The major metabolite of 2,6-DMA in rats and dogs is 4-amino-3,5-dimethylphenol (DMAP) but oxidization of the amino group to produce metabolite
- Gan,Skipper,Tannenbaum
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- Polystyrene stabilized iridium nanoparticles catalyzed chemo- and regio-selective semi-hydrogenation of nitroarenes to N-arylhydroxylamines
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Polystyrene stabilized Iridium (Ir@PS) nanoparticles (NPs) as a heterogeneous catalyst have been developed and characterized by IR, UV–Vis, SEM, TEM, EDX and XRD studies. The prepared Ir@PS catalyst showed excellent reactivity for chemo- and regio-selective controlled-hydrogenation of functionalized nitroarenes to corresponding N-arylhydroxylamine using hydrazine hydrate as reducing source and environmentally benign polyethylene glycol (PEG-400) as green solvent. The present methodology was applied for vast substrate scope and found to be compatible with wide range of reducible functional groups. The reaction performed at 85 °C or ambient temperature and completed within 5–80 minutes. The catalyst can easily be filtered out from reaction mixture and reusable.
- Bhattacherjee, Dhananjay,Das, Pralay,Kumar, Ajay,Shaifali,Zyryanov, Grigory V.
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- Redox-Neutral Selenium-Catalysed Isomerisation of para-Hydroxamic Acids into para-Aminophenols
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A selenium-catalysed para-hydroxylation of N-aryl-hydroxamic acids is reported. Mechanistically, the reaction comprises an N?O bond cleavage and consecutive selenium-induced [2,3]-rearrangement to deliver para-hydroxyaniline derivatives. The mechanism is studied through both 18O-crossover experiments as well as quantum chemical calculations. This redox-neutral transformation provides an unconventional synthetic approach to para-aminophenols.
- Chuang, Hsiang-Yu,Schupp, Manuel,Meyrelles, Ricardo,Maryasin, Boris,Maulide, Nuno
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supporting information
p. 13778 - 13782
(2021/03/31)
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- Synthesis of meta-substituted anilines via copper-catalyzed [1,3]-methoxy rearrangement
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meta-Substituted anilines were efficiently synthesized via copper-catalyzed [1,3]-methoxy rearrangement of N-methoxyanilines followed by Michael addition of nucleophiles to the in situ generated ortho-quinol imine. The present reaction exhibits excellent
- Ishida, Yasuhiro,Nakamura, Itaru,Tashiro, Hiroki,Terada, Masahiro
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supporting information
p. 3794 - 3798
(2020/06/08)
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- Bi(I)-Catalyzed Transfer-Hydrogenation with Ammonia-Borane
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A catalytic transfer-hydrogenation utilizing a well-defined Bi(I) complex as catalyst and ammonia-borane as transfer agent has been developed. This transformation represents a unique example of low-valent pnictogen catalysis cycling between oxidation states I and III, and proved useful for the hydrogenation of azoarenes and the partial reduction of nitroarenes. Interestingly, the bismuthinidene catalyst performs well in the presence of low-valent transition-metal sensitive functional groups and presents orthogonal reactivity compared to analogous phosphorus-based catalysis. Mechanistic investigations suggest the intermediacy of an elusive bismuthine species, which is proposed to be responsible for the hydrogenation and the formation of hydrogen.
- Wang, Feng,Planas, Oriol,Cornella, Josep
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supporting information
p. 4235 - 4240
(2019/04/17)
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- Regioselective installation of fluorosulfate (-OSO2F) functionality into aromatic C(sp2)-H bonds for the construction of: Para-amino-arylfluorosulfates
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The construction of para-amino-arylfluorosulfates was achieved through installation of fluorosulfate (-OSO2F) functionality into aromatic C(sp2)-H bonds by the reaction of N-arylhydroxylamine with sulfuryl fluoride (SO2Fs
- Fang, Wan-Yin,Zha, Gao-Feng,Zhao, Chuang,Qin, Hua-Li
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supporting information
p. 6273 - 6276
(2019/06/07)
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- PROCESS FOR PREPARING SUBSTITUTED N-PHENYLHYDROXYLAMINES
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The present invention relates to a process for the preparation of 2-[[[1-(4-chlorophenyl)-1H-pyrazol-3-yl]oxy]methyl] phenyl]-hydroxylamine from the correspondingly substituted nitrobenzene compound.
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Page/Page column 10
(2012/09/22)
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- NMR Study of the Monomer-Dimer Equilibria of Dimethylnitrosobenzenes in Solution. Identification of Mixed Azodioxy Dimeric Species
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The monomer-dimer equilibria of 2,6- and 3,5-dimethylnitrosobenzenes in CDCl3 solution were investigated by 1H and/or 13C NMR spectroscopy.The mixed systems nitrosobenzene + 2,6-dimethylnitrosobenzene and 2,6-dimethylnitrosobenzene + 3,5-dimethylnitrosobenzene were also studied, and mixed azodioxy dimers were identified.In all systems exchange occurs exclusively between dimer and monomer species, rates and activation energies being calculated from time-dependent 1H 1D spectra and/or 1H 2D-EXSY spectra measured at different temperatures. KEY WORDS 1H NMR 13C NMR 2,6-Dimethylnitrosobenzene 3,5-Dimethylnitrosobenzene Monomer-dimer equilibria Mixed azodioxy dimers
- Orrell, Keith G.,Stephenson, David,Rault, Thierry
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p. 368 - 376
(2007/10/02)
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- Substituent Effects on Solvent Dependence of the Bandshape of Charge-Transfer Transitions in N-Pyridinium Phenolates
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The solvatochromic absorption bands for "betaine-1", "betaine-22", and "betaine-29" (2,4,6-triphenyl-N-(4-hydroxyphenyl)-, 2,4,6-triphenyl-N-(2,6-dimethyl-4-hydroxyphenyl)- and 2,4,6-triphenyl-N-(3,5-dodecamethylene-4-hydroxyphenyl)pyridinium ions, respectively) in a range of polar, apolar, protic, aprotic solvents have been investigated.The bands can be accurately fitted by a single harmonic high-frequency mode Franck-Condon envelope of Gaussian solvent-broadened sub-bands.Multiphonon band analysis including both molecular modes and the solvent dynamics indicates that the solvent broadening for betaine-29 in polar solvents correlates well with εo-1 - εs-1, εo being the optical and εs the static dielectric constant, not only for aprotic solvents but also for normal alcohols.This is different from the behavior of 2,4,6-triphenyl-N-(3,5-di-tert-butyl-4-hydroxyphenyl)pyridinium ion ("betaine-26") for which the high-frequency solvent vibrational spectral part was previously found to be important.Bands for apolar solvents are independent of the solvent and are much wider than what corresponds to a structureless dielectric medium, pointing to other than purely electrostatic coupling mechanisms.Both the molecular frequencies and coordinate displacements are largely independent of the solvent, emphasizing their molecular character, and the frequency value of about 1600 cm-1 suggests that C-O or C-N stretching is involved.Spectral data for "betaine-1" and "betaine-22" could also be obtained for alcohol solvents and chloroform.The C-O/C-N mode at 1600 cm-1 can also be identified for these compounds.In addition, the band features suggest that coupling both to O-H stretching modes and to less isotope sensitive solvent modes is important.
- Kjaer, A. M.,Ulstrup, J.
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p. 3874 - 3879
(2007/10/02)
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- Hetero-Cope Rearrangements, III. - Vinylindoles via Hetero-Cope Rearrangement
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The reaction of N-phenylnitrones 1 with allenes 2 which are substituted with electron acceptor groups gives various products via addition and sigmatropic rearrangement depending on the specific acceptor group.In this manner one obtains 2-substituted indoles 8a, 8b, and 10 from propadienyl trichloromethyl sulfoxide.Using phenyl propadienyl sulfone a derivative 4a of tetrahydro-1-benzazepin-4-one is obtained.Reactions with allenecarbonitril proceed via several steps and yield 2-vinylindoles of type 6.Intermediate products could not be isolated.
- Blechert, Siegfried
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p. 673 - 682
(2007/10/02)
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- Kinetics and Mechanism of the Bamberger Rearrangement. Part 4. Rearrangement of Sterically Hindered Phenylhydroxylamines to 4-Aminophenols in Aqueous Sulphuric Acid Solution
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The rates of the Bamberger rearrangement of sterically hindered phenylhydroxylamines have been determined in aqueous sulphuric acid solution and the substituent effects (in particular, the steric effects) are discussed.The rate constants for phenylhydroxylamines with 2-substituents (Me, Cl, I) satisfied the Taft equation: log krel = ρ*?* - δES with ρ*-1.93 and δ-1.16.The result shows that steric hindrance of the substituents, in addition to the electron-donating effect, has an accelerating effect on the rates of the Bamberger rearrangement.The rate constants for 3-substituted 2-methylphenylhydroxylamines were generally greater than those for 5-substituted 2-methylphenylhydroxylamines.The difference was attributed to the 'buttressing effect' of neighbouring 3-substituents.This is the first example of steric acceleration of the Bamberger rearrangement.
- Sone, Takaaki,Hamamoto, Kazuhiro,Seiji, Yoshiyuki,Shinkai, Seiji,Manabe, Osamu
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p. 1596 - 1598
(2007/10/02)
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- Quantification of lidocaine and several metabolites utilizing chemical ionization mass spectrometry and stable isotope labeling
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Quantification of the suspected metabolites of lidocaine in humans was carried out using the direct insertion probe and chemical-ionization mass spectrometry. Deuterated analogs of the metabolites of lidocaine were added to serial human plasma and urine s
- Nelson,Garland,Breck,Trager
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p. 1180 - 1190
(2007/10/05)
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