Fluorinated Pyrazoles: From Synthesis to Applications

Chemical Reviews, Год журнала: 2020, Номер 121(3), С. 1670 - 1715

Опубликована: Дек. 31, 2020

Fluorinated pyrazoles play an important role in medicinal chemistry, drug discovery, agrochemistry, coordination and organometallic chemistry. Since the early 1990s, their popularity has grown exponentially. Moreover, more than 50% of all contributions on topic have been published last 5 years. In this review, analysis novel synthetic approaches to fluorinated that appeared recent years is performed. A particular emphasis devoted a detailed consideration reaction mechanisms. addition, reasons led ever-increasing various areas science are discussed. At end several potentially interesting but yet mostly unknown classes outlined.

Язык: Английский

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Recent advances in sustainable synthesis of N-heterocycles following acceptorless dehydrogenative coupling protocol using alcohols

Organic Chemistry Frontiers, Год журнала: 2021, Номер 8(11), С. 2673 - 2709

Опубликована: Янв. 1, 2021

In this review, we have summarized various aspects of homogeneous and heterogeneously catalyzed recent advancements in the synthesis heterocycles following ADC approach.

Язык: Английский

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Selective Catalytic Synthesis of α-Alkylated Ketones and β-Disubstituted Ketones via Acceptorless Dehydrogenative Cross-Coupling of Alcohols

Organic Letters, Год журнала: 2021, Номер 23(3), С. 869 - 875

Опубликована: Янв. 21, 2021

Herein, a phosphine-free pincer ruthenium(III) catalyzed β-alkylation of secondary alcohols with primary to α-alkylated ketones and two different β-branched are reported. Notably, this transformation is environmentally benign atom efficient H2O H2 gas as the only byproducts. The protocol extended gram-scale reaction for functionalization complex vitamin E cholesterol derivatives.

Язык: Английский

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Transition‐Metal‐Free Synthesis of Functionalized Quinolines by Direct Conversion of β‐O‐4 Model Compounds

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(38)

Опубликована: Июль 23, 2022

Direct production of heterocyclic aromatic compounds from lignin β-O-4 models remains a huge challenge due to the incompatible catalysis for aryl ether bonds cleavage and ring formation. Herein, first example quinoline synthesis model by one-pot cascade reaction is reported in yields up 89 %. The pathway involves selective C-O bonds, dehydrogenation, aldol condensation, C-N bond formation along with construction. control experiments suggest that both imine chalcone were identified as key intermediates, rate determining step well preferred experimentally clarified supported density functional theory (DFT) calculations. Based on this protocol, conversion polymer delivered 56 wt % yield derivative three steps. This transformation provides potential petroleum-independent choice chemicals.

Язык: Английский

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Well-Defined Phosphine-Free Manganese(II)-Complex-Catalyzed Synthesis of Quinolines, Pyrroles, and Pyridines

The Journal of Organic Chemistry, Год журнала: 2022, Номер 87(13), С. 8351 - 8367

Опубликована: Июнь 21, 2022

Herein, we report a simple, phosphine-free, and inexpensive catalytic system based on manganese(II) complex for synthesizing different important N-heterocycles such as quinolines, pyrroles, pyridines from amino alcohols ketones. Several control experiments, kinetic studies, DFT calculations were carried out to support the plausible reaction mechanism. We also detected two potential intermediates in cycle using ESI-MS analysis. Based these metal-ligand cooperative mechanism was proposed.

Язык: Английский

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Transfer Hydrogenation of Aldehydes and Ketones in Air with Methanol and Ethanol by an Air-Stable Ruthenium–Triazole Complex

ACS Sustainable Chemistry & Engineering, Год журнала: 2021, Номер 9(13), С. 4903 - 4914

Опубликована: Март 22, 2021

Coordination of 1,4-disubstituted 1,2,3-triazoles L1 and L2 with [(p-cymene)RuCl2]2 followed by dehydrochlorination in the presence a base resulted formation complexes 1 2, respectively. Both were tested for transfer hydrogenation aldehydes ketones air using ecologically benign cheap ethanol as hydrogen source catalytic amount base. Air-stable complex was proved to be an active catalyst wide variety aromatic aliphatic bearing various functionalities. Catalyst also effective carbonyls simplest primary alcohol, methanol, under aerobic conditions. Under present protocol, labile or reducible functionalities such nitro, cyano, ester groups tolerated. Good selectivity observed acyclic α,β-unsaturated carbonyls. However, this protocol not selective 2-cyclohexen-1-one both alkene keto moieties reduced. The hydrogenations are believed proceed via ruthenium-hydride intermediate. Finally, acetophenone isopropanol commonly used performed sustainable green credentials these protocols utilizing ethanol, compared help CHEM21 metrics toolkit.

Язык: Английский

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Borrowing Hydrogen and Acceptorless Dehydrogenative Coupling in the Multicomponent Synthesis of N‐Heterocycles: A Comparison between Base and Noble Metal Catalysis

European Journal of Organic Chemistry, Год журнала: 2021, Номер 2021(46), С. 6206 - 6223

Опубликована: Ноя. 4, 2021

Abstract Acceptorless dehydrogenative coupling reactions (ADC) and hydrogen transfer strategies (HT) provide a powerful tool in the multicomponent formation of N ‐ heterocycles. A broad variety complex products can be obtained starting from simple, cheap commercially available reagents. The protocols are highly atom‐efficient, as water, dihydrogen, or some cases peroxide, only by‐products. Moreover, neither further reducing oxidizing agents, nor external general required. Especially base metal‐catalyzed become ever more important. Therefore, recent years, various different manganese, iron, cobalt, nickel copper catalysts have been developed. This Minireview highlights progress that has made by using abundant metal complexes to promote cyclizations for heterocycles compares their performance with noble catalyst systems.

Язык: Английский

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Dehydrogenative Synthesis of Quinolines and Quinazolines via Ligand-Free Cobalt-Catalyzed Cyclization of 2-Aminoaryl Alcohols with Ketones or Nitriles

The Journal of Organic Chemistry, Год журнала: 2022, Номер 87(19), С. 12596 - 12607

Опубликована: Сен. 26, 2022

We present a convenient and efficient protocol to synthesize quinolines quinazolines in one pot under mild conditions. A variety of substituted were synthesized good excellent yields (up 97% yield) from the dehydrogenative cyclizations 2-aminoaryl alcohols ketones catalyzed by readily available Co(OAc)2·4H2O. This cobalt catalytic system also showed high activity reactions 2-aminobenzyl with nitriles, affording various quinazoline derivatives 95% yield). The offers an environmentally benign approach for synthesis N-heterocycles employing earth-abundant salt ligand-free

Язык: Английский

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Ruthenium pincer complex catalyzed efficient synthesis of quinoline, 2-styrylquinoline and quinazoline derivatives via acceptorless dehydrogenative coupling reactions

Catalysis Science & Technology, Год журнала: 2022, Номер 12(18), С. 5695 - 5702

Опубликована: Янв. 1, 2022

The synthesis of N-heterocycles has been considered an emerging area chemical research due to their extensive utilization in pharmaceuticals, materials science, and natural product synthesis.

Язык: Английский

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Amine Functionalized Pincer-like Azo-aromatic Complexes of Cobalt and Their Catalytic Activities in the Synthesis of Quinoline via Acceptorless Dehydrogenation of Alcohols

Organometallics, Год журнала: 2023, Номер 42(15), С. 1854 - 1868

Опубликована: Июль 6, 2023

Herein we disclose a series of phosphine-free cobalt(II)-based catalytic systems bearing redox non-innocent amine functionalized azo-aromatic pincer-like ligand for the synthesis quinoline by dehydrogenative oxidation 2-amino benzyl alcohol and subsequent coupling with ketone. All precatalysts were characterized thoroughly using various spectroscopic techniques DFT studies. The protocol was efficient versatile, providing major advances in quinoline. It also found to be applicable gram-scale quinolines as well. Several control experiments, kinetic studies, studies have proposed plausible reaction mechanism where azo-pyridine moiety acts activate α-C–H bond Co(II) → Co(I) reduction leads formation aldehyde. generated aldehyde undergoes base-catalyzed C–C result quinolines. potential controls efficiency precatalysts. Thus, complex 3 most anodic best precatalyst among complexes 1–4.

Язык: Английский

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