- Waste-minimized synthesis of C2 functionalized quinolines exploiting iron-catalysed C-H activation
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Herein we present an efficient and regioselective iron-catalyzed methodology for the external oxidant-free functionalization of quinoline-N-oxides. The protocol, based on the use of inexpensive and easily accessible FeSO4, showed broad applicability to a wide range of substrates. An additional green feature of this synthetic methodology is H2O being the only by-product. Experimental and computational investigations provide support to a mechanism based on a facile C-H activation event. The green efficiency of the process has also been carefully assessed using: (i) metrics related to the synthetic process (AE, Yield, 1/SF, MRP and RME); (ii) safety/hazard metrics (SHZI and SHI); and (iii) metrics related to the metal used as the catalyst (Abundance, OEL and ADP). In addition to the many advantages of this protocol related to the green iron catalyst used and the safety/hazard features of the process, an E-factor value of ca. 0.92 (84 to >99% reduction compared to known protocols) evidently confirms the sustainable efficiency of the procedure presented. Practical utility has also been demonstrated by performing the reaction efficiently on a multi-gram scale. This journal is
- Ferlin, Francesco,Zangarelli, Agnese,Lilli, Simone,Santoro, Stefano,Vaccaro, Luigi
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- A novel quinoline-based colorimetric fluorescent probe for hydrogen sulfide
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In this article, a novel fluorescent probe was designed and synthesized based on the quinoline structure for the detection of H2S. After optical evaluation, the probe showed good characteristics, including a fast response, high sensitivity, and good selectivity. More importantly, the probe could be directly observed by the naked eye after responding to H2S and has good application value.
- Fu, Dingqiang
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- Synthesis of (E)-2-Alkenylazaarenes via Dehydrogenative Coupling of (Hetero)aryl-fused 2-Alkylcyclic Amines and Aldehydes with a Cobalt Nanocatalyst
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To date, the synthesis of (E)-2-alkenylazaarenes via the condensation of 2-methyl N-heteroarenes with aldehydes or their equivalents has been well demonstrated. However, the direct formation of such a class of useful compounds from extensively distributed 2-alkylcyclic amine motifs remains an unresolved goal. Herein, by employing the nitrogen-silica-doped carbon (Vulcan XC-72R) as the support, we have developed a low-loading cobalt nanocatalyst (Co/N-Si-C). The combination of such a catalyst with p-nitrobenzoic acid and molecular O2 exhibits excellent catalytic performance towards the dehydrogenative coupling of (hetero)aryl-fused 2-alkylcyclic amines with aldehydes to afford the (E)-2-alkenylazaarenes. In the reaction, effective capture of the partially dehydrogenated cyclic amine motifs appears to be the key strategy to address the issue of the chemoselectivity. The developed catalytic transformation proceeds with the merits of broad substrate scope, good functional group tolerance, high atom-efficiency, use of an earth-abundant and reusable cobalt catalyst and molecular O2 as a green oxidant, which offers an important basis for the direct conversion of inert cyclic amine units into the functional frameworks.
- Zhou, Changjian,Tan, Zhenda,Jiang, Huanfeng,Zhang, Min
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p. 2887 - 2892
(2018/05/03)
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- Development of a novel series of styrylquinoline compounds as high- affinity leukotriene D4 receptor antagonists: Synthetic and structure- activity studies leading to the discovery of (±)-3-[[[3-[2-(7-chloro-2- quinolinyl)-(E)-ethenyl]phenyl][[3-(dimethylamino)-3- oxopropyl]thio]methyl]thio]propionic acid
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Based on LTD4 receptor antagonist activity of 3-(2-quinolinyl-(E)- ethenyl)pyridine (2) found in broad screening, structure-activity studies were carried out which led to the identification of 3-[[[3-[2-(7-chloro-2- quinolinyl)-(E)-ethenyl]phenyl][[3-(dimethylamino)-3- oxopropyl]thio]methyl]thio]propionic acid (1, MK-571) as a potent and orally active LTD4 receptor antagonist. These studies demonstrated that a phenyl ring could replace the pyridine in 2 without loss of activity, that 7-halogen substitution in the quinoline group was optimal for binding, that the (E)- ethenyl linkage was optimal, that binding was enhanced by incorporation of a polar acidic group or groups in the 3-position of the aryl ring, and that two acidic groups could be incorporated via a dithioacetal formed from thiopropionic acid and the corresponding styrylquinoline 3-aldehyde to yield compounds such as 20 (IC50 = 3 nM vs [3H]LTD4 binding to the guinea pig lung membrane). It was found that one of the acidic groups could be transformed into a variety of the amides without loss of potency and that the dimethylamide 1 embodied the optimal properties of intrinsic potency (IC50 = 0.8 nM on guinea pig lung LTD4 receptor) and oral in vivo potency in the guinea pig, hyperreactive rat, and squirrel monkey. The evolution of 2 to 1 involves the increase of >6000-fold in competition for [3H]LTD4 binding to guinea pig lung membrane and a >40-fold increase in oral activity as measured by inhibition of antigen-induced dyspnea in hyperreactive rats.
- Zamboni,Belley,Champion,Charette,DeHaven,Frenette,Gauthier,Jones,Leger,Masson,McFarlane,Metters,Pong,Piechuta,Rokach,Therien,Williams,Young
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p. 3832 - 3844
(2007/10/02)
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