- Practical and Selective sp3 C?H Bond Chlorination via Aminium Radicals
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The introduction of chlorine atoms into organic molecules is fundamental to the manufacture of industrial chemicals, the elaboration of advanced synthetic intermediates and also the fine-tuning of physicochemical and biological properties of drugs, agrochemicals and polymers. We report here a general and practical photochemical strategy enabling the site-selective chlorination of sp3 C?H bonds. This process exploits the ability of protonated N-chloroamines to serve as aminium radical precursors and also radical chlorinating agents. Upon photochemical initiation, an efficient radical-chain propagation is established allowing the functionalization of a broad range of substrates due to the large number of compatible functionalities. The ability to synergistically maximize both polar and steric effects in the H-atom transfer transition state through appropriate selection of the aminium radical has provided the highest known selectivity in radical sp3 C?H chlorination.
- McMillan, Alastair J.,Sieńkowska, Martyna,Di Lorenzo, Piero,Gransbury, Gemma K.,Chilton, Nicholas F.,Salamone, Michela,Ruffoni, Alessandro,Bietti, Massimo,Leonori, Daniele
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supporting information
p. 7132 - 7139
(2021/03/03)
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- HETEROCYCLIC COMPOUND AND USE THEREOF
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The present invention provides a heterocycle derivative having a superior amyloid β production inhibitory activity and use thereof. The present invention relates to a compound represented by the formula (I): wherein each symbol is as defined in the present specification, or a salt thereof.
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Page/Page column 79
(2012/06/01)
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- Carbon tetrabromide - A new brominating agent for alkanes and arylalkanes
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Quantitative catalytic bromination of alkanes, cycloalkanes, and arylalkanes with carbon tetrabromide as brominating agent was accomplished for the first time.
- Smirnov,Zelikman,Beletskaya,Golubeva,Tsvetkov,Levitskii,Kazankova
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p. 962 - 966
(2007/10/03)
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- Method for preparing α, ω-bromochloroalkanes
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The invention relates to a process for the preparation of α,ω-bromochloroalkanes. A cyclic ether is hydrobrominated and then the phase obtained is reacted, without any prior purification or separation, with thionyl chloride.
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- 10,11-Methanodibenzosuberane derivatives
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10,11-Methanodibenzosuberane derivatives, i.e., the compounds of Formula I: STR1 wherein: A is --CH2 --CH2 --, --CH2 --CHRa --CH2 --, or --CH2 --CHRa --CHRb --CH2 --, where one of Ra or Rb is H, OH, or lower acyloxy, and the other is H; R1 is H, F, Cl or Br; R2 is H, F, Cl or Br; and R3 is heteroaryl or phenyl optionally substituted with F, Cl, Br, CF3, CN, NO2 or OCHF2 ; and the pharmaceutically acceptable salts thereof, are useful chemosensitizing agents, e.g., for cancer chemotherapy, particularly for treating multidrug resistance.
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- Formation, Stability, and Reactivity of Radical Cations of 1-Bromo-n-chloroalkanes in Aqueous Solution: A Pulse Radiolysis Study
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Hydroxyl radicals are able to form solute radical cations in acidic aqueous solutions of 1-bromo-n-chloroalkanes (n=1-6).Depending on the value of n, the bromine centered radical cation stabilizes on coordination with an unoxidized bromine atom from another molecule (intermolecular) or with an unoxidized chlorine atom of the same molecule (intramolecular).With n=2, 5, and 6, only dimer radical cations (λmax=430-450 nm) are formed through intermolecular coordination whereas, with n=1, 3, and 4, radical cations are stabilized both by intra- and intermolecular coordination, forming intramolecular radical cations (λmax=380 nm) or dimer radical cations (λmax=425-440 nm) at low and high solute concentrations, respectively.Cl2.- is unable to undergo an electron transfer reaction with 1-bromo-2-chloroethane whereas SO4.- is able to react with 1-bromo-2-chloroethane with a bimolecular rate constant of 8.3 * 106 dm3 mol-1 s-1.The dimer radical cation of 1-bromo-2-chloroethane is a strong one-electron oxidant and is able to undergo electron transfer reaction with a number of molecules with high rate constant values (109 dm3 mol-1 s-1).The dimer radical cation decays by a deprotonation mechanism, and the stability constant is determined to be 147 dm3 mol-1 at 25 deg C.Quantum chemical calculations of the strength of the three-electron bond between two heteroatoms at a semiempirical level with AMI parametrization show good correlation with experimental results.Good correlation, between experimantal results and theoretical calculations, is also observed for variation of the net atomic charge over bromine, the ionization potential (IP) of the molecule, and the difficulty of oxidation of various alkyl halides.
- Maity, D. K.,Mohan, H.,Chattopadhyay, S.,Mittal, J. P.
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p. 12195 - 12203
(2007/10/02)
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- Phenothiazine derivatives, their preparation and therapeutic use
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New phenothiazine derivatives having pharmaceutical activity are disclosed. The compounds are of particular interest because of their neuroleptic activity. The compounds are suitably prepared by reacting an N-substituted phenothiazine with an O,O'-isopropylidenyl-2-methyl-3-hydroxy-4-hydroxymethyl-5-(N-piperazinylmethyl)-pyridine.
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