- Chemiluminescence of 1,1′-biisoquinolinium and 2,2′-biquinolinium salts. Reactions of electron-rich olefins with molecular oxygen
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2,2′-Dialkyl-1,1′-biisoquinolylidenes (BIQ), having been prepared by two-electron reduction of the corresponding diquaternary salts BIQ2+(X-)2, react with triplet dioxygen to produce chemiluminescence (CL). In aprotic solvents, the kinetics of the reaction are first-order with respect to the concentrations of the substrate and of oxygen. The second-order rate constants at 25°C increase in the order DMF 2, although this process is endothermic in all three solvents. In non-polar solvents such as benzene, the reaction proceeds much more slowly. From these results, a reaction mechanism is proposed as follows. An ET or partial charge-transfer gives a radical ion pair {BIQ.+ ... O2.-} or a CT complex, in which intersystem crossing takes place from the triplet to the singlet state, and then radical coupling at the 1-position followed by cyclisation yields a 1,2-dioxetane, the postulated intermediate of the CL reaction. An electron-rich olefin having a closely related structure, 1,1′-dimethyl-2,2′-bisquinolylidene (BQ), shows a similar redox behaviour to that of BIQ. Reaction of BQ with O2 produces CL, and the emitter has been identified as the singlet excited state of 1-methyl-2(1H)-quinolinone 8a. The effects of substituents in the quinoline ring on the autoxidation rate have been investigated in MeCN and DMSO. An olefin having the more negative oxidation potential shows the higher reactivity to O2, suggesting that the autoxidation of BQ should take place via a similar reaction pathway as that of BIQ.
- Mori, Yukie,Isozaki, Kumiko,Maeda, Koko
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- Harnessing selective PET and EnT catalysis by chlorophyll to synthesizeN-alkylated quinoline-2(1H)-ones, isoquinoline-1(2H)-ones and 1,2,4-trioxanes
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Photocatalytic syntheses of quinoline-2(1H)-ones, isoquinoline-1(2H)-ones and 1,2,4-trioxanes were achieved by selective photo-induced electron transfer (PET) and energy transfer (EnT), respectively, by chlorophyll under visible light irradiation. Quinoli
- Banu, Saira,Singh, Kuldeep,Tyagi, Shaifali,Yadav, Anjali,Yadav, Prem P.
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supporting information
p. 9433 - 9438
(2021/11/17)
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- Silver-Catalyzed Decarboxylative Radical Addition/Cyclization of Oxamic Acids with Alkenes towards Quinolin-2-ones
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An efficient silver-catalyzed tandem decarboxylative radical addition/cyclization of oxamic acids with alkenes has been developed. This method provides a novel and straightforward protocol toward a variety of 4-aryl-3,4-dihydroquinolin-2(1 H)-ones, 4-(α-c
- Jin, Chengan,He, Jing-Yao,Bai, Qi-Fan,Feng, Gaofeng
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p. 1517 - 1522
(2020/08/10)
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- Development of a facile and inexpensive route for the preparation of α-halobenzopyridines from α-unsubstituted benzopyridines
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A facile and inexpensive route for the preparation of α-halobenzopyridines from α-unsubstituted benzopyridines via N-methylbenzopyridin-α-ones was developed. α-Unsubstituted benzopyridines were converted easily into the corresponding N-methylbenzopyridin-α-ones, which were halogenated using PPh3-TCICA or PPh3-DBICA without using solvent to give α-halobenzopyridines.
- Sugimoto, Osamu,Iwasaki, Hyuma,Tanji, Ken-Ichi
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p. 1445 - 1454
(2015/07/15)
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- Reactive 2-quinolones dearomatized by steric repulsion between 1-methyl and 8-substituted groups
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Usual 1-methyl-2-quinolone (MeQone) derivatives are not reactive because of aromatic property in the heterocyclic ring. On the other hand, 8-substituted MeQones have been proved to be highly reactive, which is caused by steric repulsion between the 1-meth
- Chen, Xin,Kobiro, Kazuya,Asahara, Haruyasu,Kakiuchi, Kiyomi,Sugimoto, Ryuichi,Saigo, Kazuhiko,Nishiwaki, Nagatoshi
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p. 4624 - 4630
(2013/06/26)
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- Free radical cyclization reactions of alkylsulfonyl and alkylthio substituted aromatic amide derivatives
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Free radical cyclization reactions of alkylsulfonyl and alkylthio substituted aromatic amide derivatives are described. Carbon radicals can be generated efficiently from the sulfonyl radical induced reaction of allylsulfones or the oxidation of carbonyl c
- Wu, Yi-Lung,Chuang, Che-Ping,Lin, Pey-Yun
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p. 6209 - 6217
(2007/10/03)
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- Heteroaralkyl and heteroarylthioalkyl thiophenolic compounds as 5-lipoxgenase inhibitors
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Compounds of the formula: STR1 and the pharmaceutically acceptable salts thereof, pharmaceutical compositions comprising a therapeutically-effective amount of the compounds or salts in combination with a pharmaceutically-acceptable carrier and methods for
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