- Photophysics and excited-state proton transfer of 2′-hydroxy-2-trans- styrylquinoline
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2-StQ-2OH possessing a proton donor group (hydroxy) and a proton acceptor group (quinoline) was synthesized in order to study the influence of structural effects on the excited-state proton transfer (ESPT) and tautomerization. The ESPT were observed for ground-state hydrogen-bonding complex between 2-StQ-2OH and 2,2,2-trifluoroethanol (TFE) or with triethylamine. In aqueous solution, ESPT can only be observed in α-cyclodextrin (α-CD) inclusion complex. The dielectric constant values of the α-CD cavities probed by 2-StQ-2OH and 2-StQ-2OMe are 8.5 and 6.3, respectively, because of the difference in size of the probe molecule inside the cavity.
- Wang, Shun-Li,Yeh, Tzu-Wei,Ho, Tong-Ing
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- Acid-Catalyzed Synthesis of Quinoline Derivatives from 2-Methylquinolines and 2-Aryloxy/Alkoxybenzaldehyde in Aqueous Medium
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A HOAc-catalyzed aryloxy/alkoxy-assisted nucleophilic addition of 2-methylquinolines to aldehydes in water has been described. With this highly environmentally benign protocol, a series of hydroxyquinolines were efficiently prepared in moderate to good yields. In addition, a HOAc/1,3-DMBBA (1,3-dimethylbarbituric acid) synergistic organocatalysis system was also developed for the synthesis of alkenylquinolines which involved a sequence of Knoevenagel condensation, Micheal addition, and retro-Micheal addition steps.
- Wu, Yinrong,Lu, Xianchen,Wang, Hang,Liang, En,Yuan, Yingying,Zhao, Qiaorun,Zhu, Zhongzhi,Huang, Jiaping,Tang, Xiaodong
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- Method for alkenylation of methyl heterocyclic compound
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The invention discloses a method for alkenylation of methyl heterocyclic compound, which is a green method for synthesizing an alkenyl heterocyclic compound by carrying out alkenylation reaction on methyl under the condition that the methyl heterocyclic compound and alcohol do not need to participate in a transition metal catalyst. According to the method, alcohol which is cheap, easy to obtain, wide in source, stable and low in toxicity is used as an alkenylation reagent, no transition metal catalyst or ligand is needed, air can be directly used as a convenient, mild and efficient oxidizing agent under the action of common water-soluble inorganic base, and the method is suitable for industrial production. The alkenyl heterocyclic compound is directly synthesized by carrying out a Cenylation reaction with a methyl heterocyclic compound through processes such as oxidative condensation and the like. The method has the advantages of simple reaction conditions, no need of inert gas protection, low requirements on equipment, easiness in operation, water as a byproduct, easiness in removal of water-soluble inorganic base, no metal residue in the product, easiness in purification, suitability for heterocyclic systems such as quinoline, quinoxaline, pyridine, benzothiazole and the like, and wide application range, thereby having certain research significance and potential application prospect.
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Paragraph 0104-0106
(2021/02/10)
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- NaCl as Catalyst and Water as Solvent: Highly E-Selective Olefination of Methyl Substituted N-Heteroarenes with Benzyl Amines and Alcohols
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Oxidative coupling of benzylamines and alcohols with methyl substituted N-heteroarenes such as quinolines and quinoxalines has been achieved using chloride, a sea abundant anion as the catalyst for practical synthesis of a wide range of E-disubstituted olefins in aqueous medium. Detailed mechanistic studies and control experiments were carried out to deduce the reaction mechanism which indicated that in situ formed ClO2- is the active form of the catalyst. We have successfully carried out a 1 g scale reaction using this methodology, and five pharmaceutically relevant conjugated olefins were also synthesized by this method in moderate to good yields.
- Hazra, Susanta,Tiwari, Vikas,Verma, Ashutosh,Dolui, Pritam,Elias, Anil J.
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supporting information
p. 5496 - 5501
(2020/07/14)
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- Preparation method of trans-disubstituted olefin
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The invention relates to the technical field of organic chemical synthesis, and in particular, relates to a preparation method of trans-disubstituted olefin. According to the preparation method, primary alcohol and methyl azacycle are taken as raw materials, transition metal salt, nitric oxide and alkali are taken as catalysts, an organic solution is taken as a reaction medium, and reaction is carried out in an oxygen atmosphere. According to the preparation method, a reaction by-product is only water, the environment is not polluted, the required transition metal catalyst is cheap and easy toobtain, the reaction does not need high temperature, and the reaction cost and the requirements on reaction conditions can be reduced.
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Paragraph 0150-0157
(2020/02/27)
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- Iron/TEMPO-catalyzed direct aerobic oxidative coupling of methyl-mubstituted N-heteroazaarenes with alcohols
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A novel direct oxidative coupling of methyl-substituted N-heteroazaarenes with alcohols has been developed to construct olefins under mild condition. The reaction is catalyzed by Fe(NO3)3·9H2O/TEMPO with oxygen as terminal oxidant. A variety of E-disubstituted olefins bearing diverse functional groups could be obtained selectively in moderate to excellent yields. The reaction is environmentally friendly and ligand-free.
- Zhang, Zhiguang,Ma, Yantao,Dai, Siwei,Li, Ling,Zhang, Yong,Li, Hao
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supporting information
(2020/04/21)
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- MnO2 mediated sequential oxidation/olefination of alkyl-substituted heteroarenes with alcohols
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A practical and efficient ligand-free MnO2 mediated sequential oxidation and olefination has been developed for the facile synthesis of a broad range of unsaturated N-heteroazaarenes from simple alkyl-substituted heteroarenes and alcohols. The procedure tolerates a series of functional groups, such as methoxyl, chloro, bromo, iodo, vinyl, phenolic and hetero groups, providing the olefination products in moderate to good yields.The protocol could be conducted at mild conditions and used environmentally friendly air as the clear oxidant.
- Zhang, Chunyan,Li, Zehua,Fang, Yanchen,Jiang, Shaohua,Wang, Maorong,Zhang, Guoying
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supporting information
(2020/02/15)
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- Nickel-Catalyzed Direct Alkenylation of Methyl Heteroarenes with Primary Alcohols
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An efficient nickel-catalyzed acceptorless dehydrogenative coupling of methyl-substituted heteroarenes with primary alcohols is achieved using an in situ generated complex of inexpensive NiBr2 and readily available 8-aminoquinoline picolinic amide ligand. The protocol is operationally simple and scalable and furnishes a series of high-value 2-alkenylheteroarenes in good yields (up to 88percent) with exclusive E-selectivity. The reaction proceeds with the release of water and molecular hydrogen, which was analyzed through gas chromatography to validate the reaction mechanism. ?
- Baidya, Mahiuddin,Ramakrishna, Isai,Ramalingam, Bose Muthu
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p. 9819 - 9825
(2019/08/26)
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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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- Manganese-Catalyzed Dehydrogenative Alkylation or α-Olefination of Alkyl-Substituted N-Heteroarenes with Alcohols
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Catalysis with earth-abundant transition metals is an option to help save our rare noble-metal resources and is especially interesting when novel reactivity or selectivity patterns are observed. We report here on a novel reaction, namely the dehydrogenative alkylation or α-olefination of alkyl-substituted N-heteroarenes with alcohols. Manganese complexes developed in our laboratory catalyze the reaction with high efficiency whereas iron and cobalt complexes stabilized by the same ligands are essentially inactive. Hydrogen is liberated during the reaction, and bromine and iodine functional groups as well as olefins are tolerated. A variety of alkyl-substituted N-heteroarenes can be functionalized, and benzylic and aliphatic alcohols undergo the reaction.
- Zhang, Guoying,Irrgang, Torsten,Dietel, Thomas,Kallmeier, Fabian,Kempe, Rhett
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supporting information
p. 9131 - 9135
(2018/06/04)
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- A trans-substituted olefin preparation method (by machine translation)
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This invention relates to a trans-substituted olefin preparation method, which belongs to the technical field of organic chemical synthesis. The method adopts the simple alcohol and methyl nitrogen-containing heterocyclic as the starting material, by transition metal-catalyzed alkene base reaction, to obtain trans-substituted olefin compound. The reaction raw material, catalyst and additives is cheap, simple synthesis technology, greatly reduces the cost of synthesizing; mild reaction conditions, high yield, easy industrialization; the reaction of raw materials and catalyst cleaning toxic, small pollution to the environment. The trans-substituted olefin compound and its derivatives as an important fine chemicals, in the medical, agricultural chemicals, perfume and photoelectric and other industries have wide application. (by machine translation)
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Paragraph 0160; 0161; 0163; 0164
(2018/07/30)
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- Design, synthesis, and biological evaluation of 2-arylethenylquinoline derivatives as multifunctional agents for the treatment of Alzheimer's disease
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A series of new 2-arylethenylquinoline derivatives (4a1-4a12, 4b1-4b8, 4c1-4c4, 4d1-4d3 and 4e1-4e9) were designed, synthesized, and evaluated as potential multifunctional agents for the treatment of Alzheimer's disease (AD). In vitro studies showed that these synthetic compounds inhibited self-induced Aβ1-42 aggregation effectively ranged from 23.6% to 83.9% at the concentration of 20 μM, and acted as potential antioxidants and biometal chelators. Their structure-activity relationships were obtained and discussed. In particular, compound 4b1, the most active compound, displayed strong inhibitory activity with an IC50 value of 9.7 μM for self-induced Aβ1-42 aggregation, good antioxidative activity with a value of 3.9-fold of Trolox, potent inhibitory activity for cholinesterase with IC50 values of 0.2 μM and 64.1 μM against butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE), respectively. Besides, 4b1 was also capable of disassembling the self-induced Aβ1-42 aggregation fibrils with a ratio of 59.8% at 20 μM concentration, and had a good metal chelating activity. Taken together, these results suggest that compound 4b1 might be a promising lead compound for AD treatment.
- Wang, Xiao-Qin,Xia, Chun-Li,Chen, Shuo-Bin,Tan, Jia-Heng,Ou, Tian-Miao,Huang, Shi-Liang,Li, Ding,Gu, Lian-Quan,Huang, Zhi-Shu
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p. 349 - 361
(2015/05/06)
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- Oxidative olefination of secondary amines with carbon nucleophiles
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An unprecedented olefination reaction of secondary amines with carbon nucleophiles has been developed through C-N/C-H functionalization under metal-free oxidative conditions. In the presence of a stoichiometric amount of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), a range of secondary N-alkylanilines smoothly underwent oxidative olefination with 2-alkylazaarenes, acetophenone, and malononitrile to give structurally diverse polysubstituted alkenes in moderate to excellent yields with excellent (E) selectivity. Preliminary mechanistic studies revealed that the oxidative olefination reaction proceeds through amine oxidation followed by imine olefination. A range of secondary N-alkylanilines smoothly underwent DDQ-promoted oxidative olefination with 2-alkylazaarenes, acetophenone, and malononitrile to give structurally diverse alkenes in moderate to excellent yields with excellent (E) selectivity. Mechanistically, the reaction proceeds through amine oxidation followed by imine olefination (DDQ = 2,3-dichloro-5,6-dicyano-1,4-benzoquinone). Copyright
- Zhang, Yong-Gang,Xu, Jing-Kun,Li, Xi-Ming,Tian, Shi-Kai
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supporting information
p. 3648 - 3652
(2013/07/19)
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- A catalyst-free benzylic C-H bond olefination of azaarenes for direct mannich-like reactions
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A highly efficient synthesis of trans-alkenylazaarene under catalyst-free conditions was developed via the addition of methylazaarenes to N-sulfonyl aldimines and a subsequent C-N elimination in situ. A one-pot procedure for this addition-elimination was also developed. The reaction could tolerate a broad substrate scope and give the corresponding alkenylazaarenes in high yields.
- Yan, Yizhe,Xu, Kun,Fang, Yang,Wang, Zhiyong
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experimental part
p. 6849 - 6855
(2011/10/04)
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- Di- and tri-methoxystyryl derivatives of heterocyclic nitrogen compounds
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A series of mono-, di-, and trimethoxystyryl derivatives of heterocyclic nitrogen compounds were prepared to test the N-O-O triangulation hypothesis of Zee-Cheng and Cheng. Of 29 free bases submitted for KB cell culture test, only 2-(3,4-methylenedioxystyryl)benzoxazole and 4-(2,5-dimethoxystyryl)cinnoline were active (ED50 of 4 μg/ml or less). Methiodide salts were more potent: 8 of 14 were active. 2-(2,4,6-Trimethoxystyryl)quinoline methiodide and 4-(2,4,5-trimethoxystyryl)quinoline methiodide had ED50 of 0.4 and 0.9 μg/ml, respectively. The methiodides of 2-(2,3,4-, 4-(2,4,5-, 4-(2,4,6-, and 2,4-bis-(2,4,6-trimethoxystyryl)quinoline and 1-(2,4,6-trimethoxystyryl isoquinoline and the propiodide of 4-(2,4,6-trimethoxystyryl)quinoline were active against P388 leukemia. Several of the active compounds do not conform to the dimensions of the Zee-Cheng and Cheng triangle.
- Bahner,Rives,McGaha,Rutledge,Ford,Gooch,Westberry,Ziegler,Ziegler
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p. 404 - 406
(2007/10/02)
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