Gold-catalyzed post-Ugi alkyne hydroarylation for the synthesis of 2-quinolones

Gold-Catalyzed Synthesis of (Dihydro)quinolones by Cyclization of Benzaldehyde-Tethered Ynamides and Anilines

2-Quinolones represent a versatile class of compounds that are prevalent in natural and medicinally relevant molecules. Here we report a new approach to the selective formation of these structures. By gold catalysis, a range of benzaldehyde-tethered ynamides reacted with anilines, leading to 4-amino-3,4-dihydro-2-quinolones with high efficiency and excellent diastereoselectivity in dichloromethane. Interestingly, with methyl acetate as the solvent, the same reaction produced 3-aryl 2-quinolones as the major products. The use of a substoichiometric amount of the aniline could also promote this transformation.

Recent Advances in the Synthesis of Peptidomimetics via Ugi Reactions

Peptidomimetics have been extensively explored in many area due to their ability to improve pharmacological qualities and interesting biological activities. Cycles could be incorporated in peptides to reduce their flexibility, often enhancing the affinity for a certain receptor. Many efforts have been made to synthesize various peptidomimetics. Among them, the Ugi reaction is a popular way for the synthesis of peptidomimetics because it provides peptide-like products. The Ugi reaction consists of the condensation of an aldehyde or ketone, a carboxylic acid, an amine, and an isocyanide usually giving a linear peptidomimetic. In order to obtain other linear, cyclic or polycyclic peptidomimetics, the acyclic products have to undergo additional transformations or cyclizations. This review covers the years from 2018-2023, regarding the synthesis of linear, cyclic and polycyclic peptidomimetics, employing Ugi reactions eventually followed by post-Ugi transformations. Organo-catalyzed reactions, base-promoted reactions, and metal-free reactions toward peptidomimetics are highlighted.

HFIP in Organic Synthesis

1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) is a polar, strongly hydrogen bond-donating solvent that has found numerous uses in organic synthesis due to its ability to stabilize ionic species, transfer protons, and engage in a range of other intermolecular interactions. The use of this solvent has exponentially increased in the past decade and has become a solvent of choice in some areas, such as C-H functionalization chemistry. In this review, following a brief history of HFIP in organic synthesis and an overview of its physical properties, literature examples of organic reactions using HFIP as a solvent or an additive are presented, emphasizing the effect of solvent of each reaction.

Gold(I)-Catalyzed Intramolecular Hydrothiophenylation of N-Thiophen-3-yl Alkynylamides for Accessing Thieno[3,2-b]pyridine-5(4H)-ones: Development of F-Actin Specific Fluorescent Probes

Herein, we describe an original synthetic method for a series of fluorescent thieno[3,2-b]pyridine-5(4H)-one derivatives prepared via the gold(I)-catalyzed 6-endo-dig intramolecular hydrothiophenylation process involving N-thiophen-3-yl alkynylamides. The brightness was improved; emission could be tuned, and larger Stokes shifts were recorded. We also designed and synthesized the phalloidin-based fluorescent chemical probes KF-P1 and KF-P2 to realize fluorescent F-actin imaging.

Gold-Catalyzed Hydroarylation Reactions: A Comprehensive Overview

The hydroarylation of alkynes, alkene, and, allene is a cost-effective and efficient way to incorporate unsaturated moieties into aromatic substrates. This review focuses on gold-catalyzed hydroarylation, which produces aromatic alkenes,...

Exploring quinolone scaffold: Unravelling the chemistry of anticancer drug design

Globally, cancer is considered as the major leading cause in decreasing the patient health care system of human beings. The growing threat from drug-resistant cancers makes heterocyclic moieties as an urgent need to develop more successful candidates for anti-cancer therapy. In view of outstanding pharmacological activities Quinolone and its derivatives have attracted more attention towards drug designing and biological evaluation in the search of new drug molecules. The inspired researchers attempted efforts in order to discover quinolone based analogs due to its wide range of biological activities. Due to immense pharmacological importance, distinct synthetic methods have been executed to attain new drug entities from quinolones and all the reported molecules have shown constructive anticancer activity. Some of the synthetic protocol like, one pot synthesis, post-Ugi-transformation, catalysed based synthesis, enzyme-based synthesis and nano-catalyst based synthetic procedures are also discussed as recent advancement in production of quinolone derivatives. In this review, recent synthetic approaches in the medicinal chemistry of quinolones and potent quinolone derivatives on the basis of structural activity relationship are outlined. Moreover, their major methods and modifications are discussed.

Recent Advances in One-Pot Modular Synthesis of 2-Quinolones

It is known that 2-quinolones are broadly applicable chemical structures in medicinal and agrochemical research as well as various functional materials. A number of current publications about their synthesis and their applications emphasize the importance of these small molecules. The early synthetic chemistry originated from the same principle of the classical Friedländer and Knorr procedures for the preparation of quinolines. The analogous processes were developed by applying new synthetic tools such as novel catalysts, the microwave irradiation method, etc., whereas recent innovations in new bond forming reactions have allowed for novel strategies to construct the core structures of 2-quinolones beyond the bond disconnections based on two classical reactions. Over the last few decades, some reviews on structure-based, catalyst-based, and bioactivity-based studies have been released. In this focused review, we extensively surveyed recent examples of one-pot reactions, particularly in view of modular approaches. Thus, the contents are categorized as three major sections (two-, three-, and four-component reactions) according to the number of reagents that ultimately compose atoms of the core structures of 2-quinolones. The collected synthetic methods are discussed from the perspectives of strategy, efficiency, selectivity, and reaction mechanism.

Recent advances in the synthetic and medicinal perspective of quinolones: A review

In the modern scenario, the quinolone scaffold has emerged as a very potent motif considering its clinical significance. Quinolones possess wide range of pharmacological activities such as anticancer, antibacterial, antifungal, antiprotozoal, antiviral, anti-inflammatory, carbonic anhydrase inhibitory and diuretic activity etc. The versatile synthetic approaches have been successfully applied and several of the resulted synthesized compounds exhibit fascinating biological activities in numerous fields. This has prompted to discover quinolone-based analogues among the researchers due to its great diversity in biological activities. In the past few years, various new, efficient and convenient synthetic approaches (including green chemistry and microwave-assisted synthesis) have been designed and developed to synthesize diverse quinolone-based scaffolds which represent a growing area of interest in academic and industry as well as to explore their biological activities. In this review, an attempt has been made by the authors to summarize (1) One of the most comprehensive listings of quinolone-based drugs or agents in the market or under various stages of clinical development; (2) Recent advances in the synthetic strategies for quinolone derivatives as well as their biological implications including insight of mechanistic studies. (3) Further, the biological data is correlated with structure-activity relationship studies to provide an insight into the rational design of more active agents.