- Metal-Free Chemoselective Oxidation of 4-Methylquinolines into Quinoline-4-Carbaldehydes
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A convenient protocol for the synthesis of quinoline-4-carbaldehydes via chemoselective oxidation of 4-methylquinolines using hypervalent iodine(III) reagents as oxidant is described. This method highlights metal-free and mild reaction conditions, nice yield, good functional group tolerance, and high chemoselectivity.
- Xu, Jincheng,Li, Yang,Ding, Tianling,Guo, Hao
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supporting information
p. 3114 - 3117
(2021/09/03)
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- Efficient synthesis of substituted quinolines through intramolecular addition of aryl anion to carbonyl carbon
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Substituted quinolines were synthesized in three steps from the Boc amides of substituted 2-iodoanilines and alkyl vinyl ketones. This method consists of (1) N-Michael addition of the Boc amide of 2-iodoaniline to alkyl vinyl ketone in the presence of Cs2CO3 in MeCN; (2) I-Mg exchange of the adduct with 3.5 equiv of i-PrMgCl·LiCl, and (3) acid-catalyzed reaction (excess AcCl in EtOH) of the resulting alcohol. Six examples are given with good yields.
- Kobayashi, Yuichi,Igarashi, Junji,Feng, Chao,Toshifumi,Tojo
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p. 3742 - 3745
(2012/09/25)
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- Elemental fluorine Part 15. Selective direct fluorination of quinoline derivatives
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Direct fluorination of various quinoline derivatives in acidic reaction media gives fluorinated quinoline products arising from electrophilic substitution processes.
- Chambers, Richard D.,Holling, Darren,Sandford, Graham,Batsanov, Andrei S.,Howard, Judith A.K.
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p. 661 - 671
(2007/10/03)
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- Anti-mutagenic structural modification by fluorine-substitution in highly mutagenic 4-methylquinoline derivatives
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We have previously shown that fluorine-substitution at position 3 of quinoline deprived this molecule of mutagenicity, possibly due to interference with the yield of its metabolically activated form, the 1,4-hydrated 2,3-epoxide (enamine epoxide), which is directly responsible for the mutagenic modification of DNA. To further explore the possibility of a method for anti-mutagenic modification of mutagens by fluorine-substitution, 4-methylquinoline (4-MeQ), the most mutagenic form of all the quinoline derivatives examined so far, was used as a target in the present study. Five mono- and di-fluorinated derivatives of 4-MeQ, 2-fluoro-4-methylquinoline (2-F-4-MeQ), 6-F-4-MeQ, 7-F-4-MeQ, 2,6-difluoro-4-methylquinoline (2,6-diF-4-MeQ), and 2,7-diF-4-MeQ, were subjected to analysis of their structure-mutagenicity relationships. The 2-fluorinated derivatives (2-F-4-MeQ, 2,6-diF-4-MeQ, and 2,7-diF-4-MeQ) were all non-mutagenic in the Ames test. 7-F-4-MeQ was as highly mutagenic as, and 6-F-4-MeQ was less mutagenic than non-fluorinated 4-MeQ. Metabolic studies were also conducted with 4-MeQ, 2-F-4-MeQ, 6-F-4-MeQ, and 7-F-4-MeQ, using a liver microsomal enzyme fraction prepared from the 3-methylcholanthrene-treated rat. The HPLC analytical data showed that, although the metabolic patterns (hydroxylation at 4-methyl group as a main metabolic pathway and 3-hydroxylation as a minor pathway) of these four F-MeQs were similar to one another, only the 3-hydroxy metabolite of 2-F-4-MeQ was not produced under the present experimental conditions employed. These results suggest that fluorine-substitution at position 2 of 4-MeQ inhibited the formation of the enamine epoxide in the pyridine moiety and deprived this molecule of mutagenicity as in the case of quinoline. Copyright (C) 2000 Elsevier Science B.V.
- Kato, Taka-Aki,Hakura, Atsushi,Mizutani, Takaharu,Saeki, Ken-Ichi
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p. 173 - 182
(2007/10/03)
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- Addition of propargyltrimethylsilane to N-methyleneamine equivalents: Generation and electrophilic cyclization of vinylic carbocations
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Lewis acid induced N-methyleneamine equivalents from N-(methoxymethyl)anilines or 1,3,5-triphenylhexahydro-1,3,5-triazines reacted with propargyltrimethylsilanes to give N-buta-2,3-dienylanilines, 4-methylene-1,2,3,4-tetrahydroquinolines and its oxidized product of 4-methylquinolines. These products came from branching reactions of the elimination and electrophilic aromatic substitution from the same vinylic carbocation intermediate.
- Ha, Hyun-Joon,Lee, Young-Scong,Ahn, Young-Gil
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p. 2357 - 2364
(2007/10/03)
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