- Manganese catalyzed C-alkylation of methylN-heteroarenes with primary alcohols
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C-Alkylations of nine different classes of methyl-substitutedN-heteroarenes, including quinolines, quinoxalines, benzimidazoles, benzoxazoles, pyrazines, pyrimidines, pyridazines, pyridines, and triazines are disclosed. A bench stable earth-abundant Mn(i)-complex catalyzed the chemoselective hydrogen-transfer reaction utilizing a diverse range of primary alcohols as the non-fossil fuel-derived carbon source. The diversifiedN-heteroarenes (41 examples) were isolated in high yields and selectivities. Water is produced as the sole byproduct, making the protocol environmentally benign.
- Jana, Akash,Kumar, Amol,Maji, Biplab
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p. 3026 - 3029
(2021/03/29)
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- Deaminative Olefination of Methyl N-Heteroarenes by an Amine Oxidase Inspired Catalyst
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We explored the bioinspired o-quinone cofactor catalyzed aerobic primary amine dehydrogenation for a cascade olefination reaction with nine different methyl N-heteroarenes, including pyrimidines, pyrazines, pyridines, quinolines, quinoxolines, benzimidazoles, benzoxazoles, benzthiazoles, and triazines. An o-quinone catalyst phd (1,10-phenanthroline-5,6-dione) combined with a Br?nsted acid catalyzed the reaction. N-Heteroaryl stilbenoids were synthesized in high yields and (E)-selectivities under mild conditions using oxygen (1 atm) as the sole oxidant without needing transition-metal salt, ligand, stoichiometric base, or oxidant.
- Thorve, Pradip Ramdas,Maji, Biplab
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supporting information
p. 542 - 547
(2021/01/26)
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- Boric acid catalyzed chemoselective reduction of quinolines
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Boric acid promoted transfer hydrogenation of substituted quinolines to synthetically versatile 1,2,3,4-tetrahydroquinolines (1,2,3,4-THQs) was described under mild reaction conditions using a Hantzsch ester as a mild organic hydrogen source. This methodology is practical and efficient, where isolated yields are excellent and reducible functional groups are well tolerated in the N-heteroarene moiety. The reaction parameters and tentative mechanistic pathways are demonstrated by various control experiments and NMR studies. The present work can also be scaled up to obtain gram quantities and the utility of the developed process is illustrated by the transformation of 1,2,3,4-THQs into a series of biologically important molecules including the antiarrhythmic drug nicainoprol.
- Adhikari, Priyanka,Bhattacharyya, Dipanjan,Das, Animesh,Konwar, Monuranjan,Nandi, Sekhar,Sarmah, Bikash Kumar
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supporting information
p. 1214 - 1220
(2020/02/22)
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- Zinc(ii)-catalyzed intramolecular hydroarylation-redox cross-dehydrogenative coupling of N -propargylanilines with diverse carbon pronucleophiles: Facile access to functionalized tetrahydroquinolines
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Zinc(ii)-catalyzed intramolecular hydroarylation-redox cross-dehydrogenative coupling of N-propargylanilines with two types of carbon pronucleophiles (nitromethane as a sp3 carbon pronucleophile and phenylacetylenes as sp carbon pronucleophiles) proceeded to give the 2-substituted tetrahydroquinolines in good yields with 100percent atomic utilization without any additional external oxidants.
- Li, Guangzhe,Wang, Chengdong,Li, Yueqing,Shao, Kun,Yu, Guo,Wang, Shisheng,Guo, Xiuhan,Zhao, Weijie,Nakamura, Hiroyuki
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p. 7333 - 7336
(2020/07/23)
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- 2-substituted tetrahydroquinoline compound and derivative, preparation method and application thereof
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The invention belongs to the technical field of medicines and chemical engineering, and relates to a 2-substituted tetrahydroquinoline compound and a derivative, a preparation method and application thereof. The 2-substituted tetrahydroquinoline compound and the derivative thereof prepared by the invention have antimalarial activity, can be used as various medicinal key intermediates and can be applied to preparation of antitumor drugs and HIF-1 inhibitors. The preparation method is green, simplified and efficient.
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Paragraph 0061; 0206-0209
(2020/06/20)
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- Unprecedented one-pot sequence for the synthesis of tetrahydroquinoline alkaloids and preliminary evaluation of their antibacterial activity
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A novel one-pot sequence (in 2 or 3 steps) was developed for the synthesis of the tetrahydroquinoline alkaloids (±)-galipinine, (±)-cuspareine, (±)-galipeine and (±)-angustureine, and the derivative (±)-11-methoxy-5,6,6a,7,8,13-hexahydro-13a-aza-benzo[5,6]cyclohepta [1,2-a]naphthalene-12-ol from their respective Wittig adducts in moderate and high yields. The solvolytic N-methylation reaction was shown to be catalyzed by Pt0, generated in situ by reduction of PtO2. The evaluation of biofilm inhibition and antibacterial activity of the compounds against Staphylococcus aureus strains isolated from cows with mastitis revealed that the alkaloid derivative is a promising candidate for an antibiotic drug.
- Diaz-Mu?oz, Gaspar,Miranda, Izabel L.,Sartori, Suélen K.,Dias, Gabriel N. S.,Kohlhoff, Markus,Purgatod, Gislaine A.,Diaz, Marisa A. N.
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p. 2646 - 2656
(2018/11/06)
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- A concise and efficient synthesis of tetrahydroquinoline alkaloids using the phase transfer mediated Wittig olefination reaction
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The present study describes the total synthesis of 1,2,3,4-tetrahydroquinoline alkaloids (±)-galipinine, (±)-cuspareine, (±)-galipeine and (±)-angustureine, in three steps and high yields (78%, 76%, 74%, and 66%, respectively) from common aldehyde and the ylide respectives. The key step of this approach is based on an unusual Wittig reaction by using the phase transfer medium (aq. NaOH/CH2Cl2 1:1 or t-BuOK/t-BuOH/CH2Cl2 1:1), affording olefinic intermediates in high yields.
- Diaz-Mu?oz, Gaspar,Isidorio, Raquel Geralda,Miranda, Izabel Luzia,de Souza Dias, Gabriel Nunes,Diaz, Marisa Alves Nogueira
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supporting information
p. 3311 - 3315
(2017/07/27)
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- Catalytic hydrogenation with frustrated lewis pairs: Selectivity achieved by size-exclusion design of lewis acids
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Catalytic hydrogenation that utilizes frustrated Lewis pair (FLP) catalysts is a subject of growing interest because such catalysts offer a unique opportunity for the development of transition-metal-free hydrogenations. The aim of our recent efforts is to further increase the functional-group tolerance and chemoselectivity of FLP catalysts by means of size-exclusion catalyst design. Given that hydrogen molecule is the smallest molecule, our modified Lewis acids feature a highly shielded boron center that still allows the cleavage of the hydrogen but avoids undesirable FLP reactivity by simple physical constraint. As a result, greater latitude in substrate scope can be achieved, as exemplified by the chemoselective reduction of α,β-unsaturated imines, ketones, and quinolines. In addition to synthetic aspects, detailed NMR spectroscopic, DFT, and 2H isotopic labeling studies were performed to gain further mechanistic insight into FLP hydrogenation. Copyright
- Eroes, Gabor,Nagy, Krisztina,Mehdi, Hasan,Papai, Imre,Nagy, Peter,Kiraly, Peter,Tarkanyi, Gabor,Soos, Tibor
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p. 574 - 585
(2012/03/08)
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- Direct aminoalkylation of arenes, heteroarenes, and alkenes via Ni-catalyzed Negishi cross-coupling reactions
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A room-temperature Ni-catalyzed cross-coupling of aryl, heteroaryl, and alkenyl electrophiles with aminoalkylzinc bromides, readily available from the corresponding aminoalkyl chlorides via Grignard reagents, was developed. The reaction allows a convenient one-step preparation of various aminoalkyl products, including piperidine and tropane derivatives. Such functionalized amine moieties are widely present in various biologically active molecules. Aryl, heteroaryl, and alkenyl iodides, bromides, chlorides and triflates are suitable electrophiles. A short total synthesis of two natural products, (±)-galipinine and (±)-cusparine, is also reported.
- Melzig, Laurin,Dennenwaldt, Teresa,Gavryushin, Andrey,Knochel, Paul
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p. 8891 - 8906
(2011/12/15)
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- Synthesis of alkaloids of Galipea officinalis by alkylation of an α-amino nitrile
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A new synthetic approach directed towards the synthesis of naturally occurring 2-alkyl-tetrahydroquinolines is described. The C-C bonds in the α position relative to the nitrogen atom were formed by the reversal of the polarity of the C=N bond of α-amino nitrile 6, which was prepared electrochemically from 1-(phenylethyl)-tetrahydroquinoline. A NaBH 4-mediated reductive decyanation process furnished benzylic amines 16a-d as mixtures of diastereomers (50-60% de). The catalytic hydrogenolysis of these amines was performed in the presence of Pearlman's catalyst to give the tetrahydroquinolines 17a-d in yields ranging from 70% to 95%. Methylation of the free nitrogen atom afforded the title compounds 1-4 in 70-90% yields. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Shahane, Saurabh,Louafi, Fadila,Moreau, Julie,Hurvois, Jean-Pierre,Renaud, Jean-Luc,Van De Weghe, Pierre,Roisnel, Thierry
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experimental part
p. 4622 - 4631
(2009/05/07)
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- Rapid synthesis of the tetrahydroquinoline alkaloids: angustureine, cuspareine and galipinine
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A one-pot method for the preparation of 1,2-substituted dihydroquinolines is described. This method features the C-2 addition of a range of organolithium reagents to quinoline followed by the in-situ addition of an electrophile. Standard palladium-catalys
- O'Byrne, Aisling,Evans, Paul
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p. 8067 - 8072
(2008/12/21)
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- A SIMPLE REGIOSELECTIVE PREPARATION OF 2- OR 3-SUBSTITUTED QUINOLINE DERIVATIVES VIA DIALKYLQUINOLYLBORANES
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Various quinoline derivatives possessing a substituent at the 2- or 3-position were prepared by the reaction of dialkylquinolylboranes and organic bromides in the presence of a palladium catalyst.
- Ishikura, Minoru,Oda, Izumi,Terashima, Masanao
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p. 2375 - 2386
(2007/10/02)
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