NaCl as Catalyst and Water as Solvent: Highly E-Selective Olefination of Methyl Substituted N-Heteroarenes with Benzyl Amines and Alcohols

Organic Letters, Год журнала: 2020, Номер 22(14), С. 5496 - 5501

Опубликована: Июнь 30, 2020

Oxidative coupling of benzylamines and alcohols with methyl substituted N-heteroarenes such as quinolines quinoxalines has been achieved using chloride, a sea abundant anion the catalyst for practical synthesis wide range E-disubstituted olefins in aqueous medium. Detailed mechanistic studies control experiments were carried out to deduce reaction mechanism which indicated that situ formed ClO2- is active form catalyst. We have successfully 1 g scale this methodology, five pharmaceutically relevant conjugated also synthesized by method moderate good yields.

Язык: Английский

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Recent advances on non-precious metal-catalyzed C–H functionalization of N-heteroarenes

Chemical Communications, Год журнала: 2021, Номер 58(1), С. 10 - 28

Опубликована: Ноя. 18, 2021

N-Heteroarenes are widely used for numerous medicinal applications, lifesaving drugs and show utmost importance as intermediates in chemical synthesis. This feature article highlights the recent advances, from 2015 to August 2021, on sp2 sp3 C-H bond functionalization reactions of various N-heteroarenes catalyzed by non-precious transition metals (Mn, Co, Fe, Ni, etc.). The salient features report are: (i) development newer catalysis Csp2-H activation categorized into alkylation, alkenylation, borylation, cyanation, annulation reactions, (ii) advances Csp3-H considering approaches alkylation well alkenylation processes, (iii) synthetic applications practical utility catalytic protocols utilized late-stage drug development; (iv) scope along with mechanistic studies detail findings important processes.

Язык: Английский

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Palladium complexes containing NNN pincer type ligands and their activities in Suzuki-Miyaura cross coupling reaction

Heliyon, Год журнала: 2023, Номер 9(7), С. e17608 - e17608

Опубликована: Июнь 27, 2023

Five new NNN pincer-type ligands and their palladium complexes were successfully synthesised characterised by FT-IR, 1H NMR, 13C UV–vis analyses. TEM analysis was used to observe the morphological character of black residues obtained from fourth cycle reusability test. Furthermore, suitable crystals N2,N6-bis(2-tert-butylphenyl)pyridine-2,6-dicarboxamide its complex elucidated with X-ray single crystal diffraction method. Both ligand crystallise in a monoclinic system space group P21/c for H2L4 C2/c complex. The structure pincer stabilised intramolecular intermolecular C–H⋅⋅⋅O, C–H⋅⋅⋅N, N–H⋅⋅⋅N contacts. A Suzuki-Miyaura cross-coupling reaction between aryl halides phenylboronic acid assess catalytic abilities complexes. All prepared exhibited considerable activity. However, 4 (Acetonitrile-N2,N6-bis(2-tert-butylphenyl)pyridine-2,6-dicarboxamidopalladium(II)) 5 (Acetonitrile-N2,N6-bis(2-nitrophenyl)pyridine-2,6-dicarboxamidopalladium(II)) provided almost 100% conversion nearly yield 4-bromotoluene acid. these active catalysed sterically hindered deactivated substrates (1-Bromo-4-izobutylbenzene 2-bromo-6-methoxynaphthalene) acid, complete yields up achieved short time 2-bromo-6-methoxynaphthalene.

Язык: Английский

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Iron-catalysed alkylation of 2-methyl and 4-methyl azaarenes with alcohols via C–H bond activation

Chemical Communications, Год журнала: 2020, Номер 56(35), С. 4777 - 4780

Опубликована: Янв. 1, 2020

The first Fe-catalysed alkylation of 2-methyl and 4-methyl-azaarenes with a series alkyl hetero-aryl alcohols is reported (>39 examples up to 95% yield). Multi-functionalisation pyrazines synthesis anti-malarial drug (±) Angustureine significantly broaden the scope this methodology. Preliminary mechanistic investigation, deuterium labeling kinetic experiments including trapping enamine intermediate 1a' are special importance.

Язык: Английский

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Atom‐Economic Alk(en)ylations of Esters, Amides, and Methyl Heteroarenes Utilizing Alcohols Following Dehydrogenative Strategies

Asian Journal of Organic Chemistry, Год журнала: 2021, Номер 10(3), С. 464 - 484

Опубликована: Янв. 19, 2021

Abstract Owing to the atom‐economic and greener nature, borrowing hydrogen (BH) acceptorless dehydrogenative coupling (ADC) processes have drawn significant attentions of researchers across globe thus, these strategies been extensively utilized in synthetic chemistry access various challenging valuable compounds. During last decade, progress has witnessed utilization protocols involving alkylation amides/esters/N‐heteroarenes by replacing traditionally mutagenic reagents as alkyl source with sustainable biomass derived alcohols under BH/ADC process. This includes mainly transition metal based catalytic systems although a few metal‐free are reported. In this minireview, advancement from 2010 until September 2020 accessing C‐alk(en)ylated compounds unactivated utilizing via strategy is highlighted. Additionally, reports on aldehydes instead partners also discussed.

Язык: Английский

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Nickel‐Catalyzed Sequential Synthesis of Alkylated Quinolines and Their Photophysical Studies

Asian Journal of Organic Chemistry, Год журнала: 2024, Номер unknown

Опубликована: Июнь 20, 2024

Abstract An efficient nickel‐catalyzed sequential one‐pot strategy for the synthesis of coumarin‐appended quinolines and bis‐quinolines has been developed under mild reaction conditions in moderate to good yields (up 84 %) via dehydrogenative Friedlander annulation followed by C(sp 3 )−H functionalization. The use a cost‐effective Ni catalyst, environmentally friendly solvents simple operating procedures are attractive attributes this method. Additionally, photophysical properties synthesized derivatives were explored utilizing UV‐vis absorption fluorescence emission studies. Furthermore, large‐scale synthetic utility highlight potential applicability organic chemistry. Moreover, A plausible mechanism is supported control experiments monitoring 1 H NMR analysis.

Язык: Английский

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Transition metal-catalyzed olefination of alkyl heteroarenes with alcohols

Tetrahedron, Год журнала: 2024, Номер 168, С. 134306 - 134306

Опубликована: Окт. 18, 2024

Язык: Английский

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(E)‐Selective Olefination by a Cofactor‐Inspired Quinone Catalysis

ChemCatChem, Год журнала: 2025, Номер unknown

Опубликована: Май 21, 2025

Abstract In this study, we report a photothermal method that prepares ( E )‐olefins from methyl‐substituted heteroarenes under very mild reaction conditions. The photocatalyst is pyrene dione (PD) molecule has significant absorbance in the visible light spectrum and can afford persistent semiquinonate radical owing to π‐delocalized backbone. This conducts hydrogen atom transfer reactions facilitate dehydrogenation of large number alcohols. Leveraging on dehydrogenating ability PD easily 2e − /2H + redox shuttles, olefination was conducted heteroarene methyl, fluorenes Furthermore, catalytic process works aerobic conditions since oxygen regenerates catalyst. methodological development improvement over many transition metal catalysts for task, which often work at high temperature anaerobic

Язык: Английский

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Synthesis, crystal structure, DFT calculations, and Hirshfeld surface analysis of an NNN pincer type compound

Journal of Molecular Structure, Год журнала: 2023, Номер 1283, С. 135252 - 135252

Опубликована: Фев. 28, 2023

Язык: Английский

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Alcohols as Fluoroalkyl Synthons: Ni‐catalyzed Dehydrogenative Approach to Access Polyfluoroalkyl Bis‐indoles

Chemistry - A European Journal, Год журнала: 2020, Номер 26(70), С. 16649 - 16654

Опубликована: Сен. 25, 2020

Abstract An acceptorless dehydrogenative strategy for the synthesis of polyfluoroalkylated bis‐indoles is described by employing an earth‐abundant nickel‐based catalytic system under air. The notable feature present transformation use bench stable and easily affordable polyfluorinated alcohols without any pre‐functionalization introduction precious polyfluoroalkyl groups. developed straightforward protocol accomplished biologically relevant fluoroalkyl in a sustainable fashion. Extensive DFT study predicts unique role indole molecules which stabilizes transition states during dehydrogenation process alcohols, presumably through non‐covalent π⋅⋅⋅π H‐bonding interactions.

Язык: Английский

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