Synthesis Of 2-pyridones Research Articles

Water extract of incense stick ash: an efficient, greener approach for the synthesis of 2-pyridones via multi-component reaction approach

Water extract of incense stick ash: an efficient, greener approach for the synthesis of 2-pyridones via multi-component reaction approach

Streamlining the Synthesis of Pyridones through Oxidative Amination of Cyclopentenones

AbstractHerein we report the development of an oxidative amination process for the streamlined synthesis of pyridones from cyclopentenones. Cyclopentenone building blocks can undergo in situ silyl enol ether formation, followed by the introduction of a nitrogen atom into the carbon skeleton with successive aromatisation to yield pyridones. The reaction sequence is operationally simple, rapid, and carried out in one pot. The reaction proceeds under mild conditions, exhibits broad functional group tolerance, complete regioselectivity, and is well scalable. The developed method provides facile access to the synthesis of 15N‐labelled targets, industrially relevant pyridone products and their derivatives in a fast and efficient way.

Streamlining the Synthesis of Pyridones through Oxidative Amination of Cyclopentenones.

Herein we report the development of an oxidative amination process for the streamlined synthesis of pyridones from cyclopentenones. Cyclopentenone building blocks can undergo in situ silyl enol ether formation, followed by the introduction of a nitrogen atom into the carbon skeleton with successive aromatisation to yield pyridones. The reaction sequence is operationally simple, rapid, and carried out in one pot. The reaction proceeds under mild conditions, exhibits broad functional group tolerance, complete regioselectivity, and is well scalable. The developed method provides facile access to the synthesis of 15N-labelled targets, industrially relevant pyridone products and their derivatives in a fast and efficient way.

Hydrogen bond assisted reactivity of Ylidineketonitriles with 1° amines: A chemoselective synthesis of 2-pyridone and 2-aminopyridine derivatives

Ylidineketonitrile 2 with chlorodifluoromethyl (A = Cl) demonstrated a strong solvent dependence reaction with primary amines to form either 1-N-alkylated-3,5-disubstituted-2-pyridones or 2-N-alkylated-3, 5-trisubstituted pyridines. The methodology was tested for its scope with primary amines and synthesized 29 derivatives in good to excellent yield. Ylidineketonitrile 2e preferrentially forms pyridone derivatives in the majority of the solvents screened except trifluoroethanol, where chemoselective formation of 2-aminopyridine derivatives was observed.

Switchable Regioselective C-H Activation/Annulation of Acrylamides with Alkynes for the Synthesis of 2-Pyridones.

A catalyst-based switchable regioselective C-H activation/annulation of acrylamides with propargyl carbonates has been developed, delivering C5 or C6 alkenyl substituted 2-pyridones. This robust protocol proceeds with a broad substrate scope and good functional group tolerance under redox-neutral reaction conditions. More significantly, this reaction is highly effective with previously challenging unsymmetrical alkynes, including unbiased alkyl-alkyl substituted alkynes, with perfect and switchable regioselectivity. Additionally, mechanistic studies and DFT calculations were performed to shed light on the switchable regioselectivity.

Ten Years of Progress in the Synthesis of 2-Pyridone Derivatives via Three / Four Component Reaction

Abstract: 2-pyridones represents ubiquitous scaffolds often present in both natural products and pharmaceutical compounds. Due to their wide applications in medicinal chemistry, it is not surprising that the synthesis of 2-pyridone derivatives has attracted organic chemists for many years. This mini review focuses on the recent development in the multi-component synthesis of 2-pyridones for the period 2011 to 2021, particularly those that involve the three/four component reactions of activated methylene, aldehyde or ketone withdifferent intermediate materials under different conditions.

Rhodium-catalyzed regioselective C–H activation/Lossen rearrangement/annulation for the green synthesis of trisubstituted 2-pyridones

A green and novel approach for the synthesis of 2-pyridone derivatives by a rhodium-catalyzed C–H activation/Lossen rearrangement of acrylamides and propargyl alcohols is reported.

Keggin heteropolyacid in auto-tandem catalysis: confinement effects over ordered mesoporous silica in the synthesis of 2-pyridones

The inherent duality of active sites in Keggin acid (H3PW12O40) is explored under its confinement over ordered mesoporous silicas such as SBA-15 and MCF in the multicatalytic synthesis of 2-pyridones through auto-tandem catalysis.

L‐Proline Catalyzed Synthesis of Steroidal Pyridones And Their DFT Studies

AbstractA steroidal‐based synthetic protocol has been developed for the synthesis of substituted steroidal pyridones in the presence of L‐proline. A wide variety of steroidal pyridones were synthesized in better yields. Initially, steroidal benzylidenes were prepared by the aldol condensation of pregnenolone with various substituted aromatic aldehydes under basic conditions. After that heterocyclization of resulting benzylidenes with cyanoacetamide in the presence of L‐proline gives the desired products. With the mild reaction conditions, good conversions, operational simplicity, and inexpensive and readily available catalyst, it is a practical and appealing approach for pyridone synthesis. Structural and quantum chemical insights of synthesized steroidal pyridone derivatives have been also presented using the density functional theory (DFT) approach.

Synthesis of 2-Pyridones by Ring Expansion of Furans or γ-Lactams

Key words pyridones - photoredox reaction - lactams - furans - ring expansion

Ruthenium (VIII) Catalysed Dearomative Pyridyl C−X Activation: Direct Synthesis of N‐ Alkyl‐2‐pyridones

AbstractAn efficient synthetic strategy employing pyridyl C−X activation, for the generation of N‐alkyl‐2‐pyridones from N‐alkyl‐2‐halopyridinium salts is described. As pyridones are dearomatised synthetic derivatives of pyridines, a versatile scope exist for pyridyl C−H functionalisation. The present strategy exemplifies a straight forward in‐situ generation of Ru(VIII), leading catalytic dearomative synthesis of pyridones. The N‐alkyl‐2‐pyridones are further reduced to N‐alkyl‐2‐piperidones and a plausible mechanism is also drawn, which is supported by some controlled reactions.

Icilio Guareschi and his amazing "1897 reaction".

Organic chemistry honors Icilio Guareschi (1847–1918) with three eponymic reactions, the best known ones being the Guareschi synthesis of pyridones and the Guareschi–Lustgarten reaction. A third Guareschi reaction, the so-called “Guareschi 1897 reaction”, is one of the most unusual reactions in organic chemistry, involving the radical-mediated paradoxical aerobic generation of hydrocarbons in near-neutral water solution. A discussion of the mechanism of this amazing reaction, the only metal-free process that generates hydrocarbons, and the implications of the approach in biology and geosciences mirrors the multifaceted scientific personality of the discoverer. Thus, Guareschi’s eclectic range of activities spans a surprising variety of topics, overcoming the boundaries of the traditional partition of chemistry into organic, inorganic, and analytical branches and systematically crosses the divide between pure and applied science as well as between the history of chemistry and the personal contributions to its development.

Selective C(sp3)–H Cleavage of Enamides for Synthesis of 2-Pyridones via Ligand-Enabled Ni–Al Bimetallic Catalysis

Previously reported direct C–H functionalization reactions of enamides mainly occurred at vinylic C(sp2)–H bonds because of their relatively high reactivity, while less reactive β′-C(sp3)–H activat...

RECENT ADVANCES IN THE SYNTHETIC APPROACHES TO 2-PYRIDONES

This microreview focuses on the methodologies for the synthesis of 2-pyridones and their biological applications. Various types of synthetic methods reported in the last 6 years (starting from the year 2014 and onward) have been discussed. Functionalization reactions of 2-pyridones have not been taken into account.

Recent advances in the synthetic approaches to 2-pyridones (microreview)

This microreview focuses on the methodologies for the synthesis of 2-pyridones and their biological applications. Various types of synthetic methods reported in the last 6 years (starting from the year 2014 and onward) have been discussed. Functionalization reactions of 2-pyridones have not been taken into account.

Ruthenium‐Catalyzed Double C(sp2)−H Functionalizations of Fumaramides with Alkynes for the Divergent Synthesis of Pyridones and Naphthyridinediones

AbstractTransition‐metal‐catalyzed C−H functionalization of aromatic secondary amides with alkynes mainly undergo C−H/N−H annulation but rarely undergo ortho‐alkenylation. It is particularly challenging to selectively realize both oxidative annulation and ortho‐alkenylation of aromatic secondary amides with alkynes in the transition‐metal‐catalysis. In this article, we synthesized fully‐substituted 2‐pyridones and 2,6‐naphthyridine‐1,5‐diones via C(sp2)−H functionalization of fumaramides for the first time. Under the Ru‐catalysis, fumaramides and 1,2‐diaryl ethynes first undergo C−H/N−H annulation leading to the intermediate 2‐pyridone with an exocyclic secondary amide, and subsequently undergo the unexpected stereoselective C−H alkenylation to realize fully substituted 2‐pyridones bearing an exocyclic anti alkenyl group. On the addition of K2CO3, however, the transformation of fumaramides with 1,2‐dialkyl ethyne undergoes two conventional C−H/N−H annulations to provide 2,6‐naphthyridine‐1,5‐diones in high yield. The two procedures can be successfully enlarged to gram‐scales without erosion of the yields. In addition, some 2‐pyridones and 2,6‐naphthyridine‐1,5‐diones emitting clear ultraviolent and fluorescent light, indicating the potential utility of this work in organic light‐emitting materials.

Synthesis of 2-Pyridone from 2-Thiopyridines via Nucleophilic Aromatic Substitution Reaction

Synthesis of 2-Pyridone from 2-Thiopyridines via Nucleophilic Aromatic Substitution Reaction

Selective synthesis of pyridyl pyridones and oxydipyridines by transition-metal-free hydroxylation and arylation of 2-fluoropyridine derivatives.

An efficient protocol for the construction of various pyridyl pyridone and oxydipyridine derivatives through a hydroxylation and arylation tandem reaction of 2-fluoropyridines is reported. Under simple transition-metal-free conditions, the reaction provided a series of products in good to excellent yields, and their structures were confirmed by crystal diffraction analysis. Furthermore, the controlling effect of 6-position substituents on the highly selective synthesis of pyridone and oxydipyridine was studied.

C-H Pyridonation of (Hetero-)Arenes by Pyridinium Radical Cations.

Pyridones are important heteroaromatic scaffolds found in natural products and pharmaceuticals and are, therefore, of major interest in organic synthetic chemistry. Here we report the first C-H pyridonation of unactivated (hetero-)arenes, providing a methodology to directly access N-aryl-2- and 4-pyridones. Generation of pyridinium radical cations through single-electron reduction allows for the synthesis of pyridones on structurally complex molecules.

Transition-metal-free highly efficient synthesis of 2-pyridones from β-keto amides and ynals

A convenient and efficient annulation reaction was developed, affording 2-pyridones in good to excellent yields. A variety of substituted β-keto amides and ynals were well tolerated, and especially the transformation produced water as only by-product under transition-metal-free conditions. Furthermore, the conjugated enyneamides were achieved from β-cyano amides and ynals in high yields.