- Preparation of an Arenylmethylzinc Reagent with Functional Groups by Chemoselective Cross-Coupling Reaction of Bis(iodoazincio)methane with Iodoarenes
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Palladium-catalyzed cross-coupling reaction of bis(iodozincio)methane with iodoarenes carrying various functionalities such as ester, boryl, cyano, and halo groups proceeded chemoselectively to give the corresponding arenylmethylzinc species efficiently. The moderate reactivity of the gem-dizinc reagent imparted functional group tolerance to the process. The transformations from iodoheteroarenes were also performed; in the case of iodopyridine derivatives, the nickel-catalyzed reaction gave the corresponding organozinc species efficiently. The obtained arenylmethylzinc species underwent the copper-mediated coupling reaction with a range of organic halides.
- Shimada, Yukako,Haraguchi, Ryosuke,Matsubara, Seijiro
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p. 2395 - 2398
(2015/10/19)
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- Synthesis of some fluorine-containing pyridinealdoximes of potential use for the treatment of organophosphorus nerve-agent poisoning
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Fluoroheterocyclic aldoximes were screened as therapeutic agents for the treatment of anticholinesterase poisoning. 2-Fluoropyridine-3- and -6-aldoxime, and 3-fluoropyridine-2- and -4-aldoxime, were synthesised. Attempts to obtain 3,5,6-trifluoropyridine-2,4-bis(aldoxime) and -2-aldoxime, however, proved unsuccessful. Pentafluorobenzaldoxime was prepared by oximation of pentafluorobenzaldehyde. Acid dissociation constants (pKa) and second-order rate constants (kox-) of the fluorinated pyridinealdoximes towards sarin were measured. 2,3,5,6-Tetrafluoropyridine-4- aldoxime had the best profile: its kox- approached that of the therapeutic oxime P2S (310 vs. 120 l mol-1 min-1), but its higher pKa (9.1 vs. 7.8) fell short of the target figure of 8 required for reactivation of inhibited acetylcholinesterase in vivo. N-alkylation of the fluorinated pyridine-aldoximes may reduce their pK a nearer to 8 and enhance their therapeutic potential. Crown Copyright
- Timperley, Christopher M.,Banks, R. Eric,Young, Ian M.,Haszeldine, Robert N.
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scheme or table
p. 541 - 547
(2011/09/15)
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- Carboxamidation of pyridines by the system of elemental fluorine- carbonitrile-water: A useful alternative to the chichibabin amination
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The title reaction with pyridine, 4-methylpyridine, 3-methylpyridine, 3- bromopyridine, nicotinonitrile, and quinoline yields 2-carboxamido derivatives regioselectively. Isoquinoline is amidated at position 1.
- Kiselyov,Strekowski
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p. 2387 - 2392
(2007/10/02)
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- DIRECT FLUORINATION OF SUBSTITUTED PYRIDINES
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The direct fluorination of pyridines bearing alkyl, halogen, ester, or ketone functions has been employed to prepare the corresponding 2-fluoro-substituted pyridines.
- Puy, Michael Van Der
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p. 255 - 258
(2007/10/02)
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