375395-24-7Relevant articles and documents
NaCl as Catalyst and Water as Solvent: Highly E-Selective Olefination of Methyl Substituted N-Heteroarenes with Benzyl Amines and Alcohols
Hazra, Susanta,Tiwari, Vikas,Verma, Ashutosh,Dolui, Pritam,Elias, Anil J.
, p. 5496 - 5501 (2020/07/14)
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.
Continuous Flow Synthesis of Quinolines via a Scalable Tandem Photoisomerization-Cyclization Process
Di Filippo, Mara,Baumann, Marcus
, p. 6199 - 6211 (2020/08/26)
A continuous photochemical process is presented that renders a series of quinoline products via an alkene isomerization and cyclocondensation cascade. It is demonstrated that a high-power LED lamp generates the desired targets with higher productivity and efficiency than a medium-pressure Hg-lamp. The scope of this tandem process is established and allows for the generation of various substituted quinolines in high yields and with throughputs of greater than one gram per hour. Finally, this effective flow process is coupled with a telescoped hydrogenation reaction to render a series of tetrahydroquinolines including the antimalarial natural product galipinine.
Iron-Catalyzed Coupling of Methyl N-Heteroarenes with Primary Alcohols: Direct Access to E-Selective Olefins
Das, Jagadish,Vellakkaran, Mari,Sk, Motahar,Banerjee, Debasis
, p. 7514 - 7518 (2019/10/02)
An efficient Fe-catalyzed system is reported for direct α-olefination of methyl-substituted N-heteroarenes with primary alcohols. The catalytic dehydrogenative coupling enables a series of functionalized E-olefinated N-heteroaromatics with excellent selectivity (>99%). Initial mechanistic studies including deuterium-labeling experiments provide evidence for the participation of the benzylic C-H/D bond of alcohols.
Sustainable synthesis of N-heterocycles in water using alcohols following the double dehydrogenation strategy
Maji, Milan,Chakrabarti, Kaushik,Panja, Dibyajyoti,Kundu, Sabuj
, p. 93 - 102 (2019/04/05)
The present study describes the first example of synthesis of pharmaceutically relevant N-heterocycles like substituted quinolines, acridines and 1,8-naphthyridines in water under air using alcohols in presence of a new water soluble Ir-complex. The viability and efficiency of this approach was demonstrated by the efficient synthesis of biologically active natural product (±)-galipinine and gram scale synthesis of various N-heteroaromatics. Several kinetic experiments and DFT calculations were carried out to support the plausible reaction mechanism which disclosed that this system followed a concerted outer sphere mechanism for the dehydrogenation of alcohols.
Silver-Catalyzed Reduction of Quinolines in Water
Wang, Yan,Dong, Baobiao,Wang, Zikun,Cong, Xuefeng,Bi, Xihe
supporting information, p. 3631 - 3634 (2019/05/24)
A ligand- and base-free silver-catalyzed reduction of quinolines and electron-deficient aromatic N-heteroarenes in water has been described. Mechanistic studies revealed that the effective reducing species was Ag-H. This versatile catalytic protocol provided facile, environmentally friendly, and practical access to a variety of 1,2,3,4-tetrahydroquinoline derivatives at room temperature.
Nickel-catalysed direct α-olefination of alkyl substituted N-heteroarenes with alcohols
Das, Jagadish,Vellakkaran, Mari,Banerjee, Debasis
supporting information, p. 7530 - 7533 (2019/07/04)
Catalytic α-olefination of alkylheteroarenes with primary alcohols via dehydrogenative coupling is presented. A simple nickel catalyst system stabilised by readily available nitrogen ligands enables a series of interesting E-configured vinylarenes (confirmed by X-ray crystal-structure analysis) to be synthesised in good to excellent yields with olefin/alkane selectivity of >20:1. Hydrogen and water are generated as byproducts and quantitative determination of H2 was performed.
Synergistic Chemo/Biocatalytic Synthesis of Alkaloidal Tetrahydroquinolines
Cosgrove, Sebastian C.,Hussain, Shahed,Turner, Nicholas J.,Marsden, Stephen P.
, p. 5570 - 5573 (2018/05/25)
The power of complementary chemocatalytic and biocatalytic transformations is demonstrated in the asymmetric synthesis of 2-substituted tetrahydroquinolines. A series of racemic tetrahydroquinolines were synthesized through a convergent one-pot Rh(I)-catalyzed addition/condensation sequence of alkyl vinyl ketones and aminophenylboronic acids. The resulting tetrahydroquinolines were thereafter shown to be substrates for the flavin-dependent enzyme cyclohexylamine oxidase, and preparative-scale deracemizations have been demonstrated on these high-value targets.
Nanolayered Cobalt-Molybdenum Sulfides as Highly Chemo- and Regioselective Catalysts for the Hydrogenation of Quinoline Derivatives
Sorribes, Iván,Liu, Lichen,Doménech-Carbó, Antonio,Corma, Avelino
, p. 4545 - 4557 (2018/05/22)
Herein, a general protocol for the preparation of a broad range of valuable N-heterocyclic products by hydrogenation of quinolines and related N-heteroarenes is described. Interestingly, the catalytic hydrogenation of the N-heteroarene ring is chemoselectively performed when other facile reducible functional groups, including alkenes, ketones, cyanides, carboxylic acids, esters, and amides, are present. The key to successful catalysis relies on the use of a nanolayered cobalt-molybdenum sulfide catalyst hydrothermally synthesized from earth-abundant metal precursors. This heterogeneous system displays a tunable composition of phases that allows for catalyst regeneration. Its catalytic activity depends on the composition of the mixed phase of cobalt sulfides, being higher with the presence of Co3S4, and could also be associated with the presence of transient Co-Mo-S structures that mainly vanish after the first catalytic run.
Iodine catalyzed reduction of quinolines under mild reaction conditions
Yang, Chun-Hua,Chen, Xixi,Li, Huimin,Wei, Wenbo,Yang, Zhantao,Chang, Junbiao
, p. 8622 - 8625 (2018/08/06)
A reduction of quinolines to synthetically versatile tetrahydroquinoline molecules with I2 and HBpin is described. In the presence of iodine (20 mol%) as a catalyst, reduction of quinolines and other N-heteroarenes proceeded readily with hydroboranes as the reducing reagents. The broad functional-group tolerance, good yields and mild reaction conditions imply high practical utility.
Unprecedented one-pot sequence for the synthesis of tetrahydroquinoline alkaloids and preliminary evaluation of their antibacterial activity
Diaz-Mu?oz, Gaspar,Miranda, Izabel L.,Sartori, Suélen K.,Dias, Gabriel N. S.,Kohlhoff, Markus,Purgatod, Gislaine A.,Diaz, Marisa A. N.
, p. 2646 - 2656 (2018/11/06)
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.
