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1,2,3,4-Tetrahydroquinolines (THQs) are present in molecules with significant biological importance and pharmaceuticals with diverse biological activities. Various synthetic routes have been developed to tetrahydroquinolines, such as the hydrogenation of quinolines, domino reactions, intramolecular cyclization, and notably, the Povarov reaction. Organocatalysts are small, chiral organic molecules that can successfully catalyze organic transformations. This review examines the use of organocatalysts in the asymmetric synthesis of tetrahydroquinoline derivatives using aminocatalysis, NHC catalysis, and H-bonding catalysis covering the literature between 2000 and early 2024. 1 Introduction 2 Aminocatalysis 3 NHC Catalysis 4 H-Bonding Catalysis 5 Miscellaneous 6 Conclusion [ABSTRACT FROM AUTHOR]

This review highlights the multifaceted usefulness of o -halobenzyl halides as pivotal substrates for the construction of five- to nine-membered cyclic structures with the aid of transition metals as catalysts. These privileged entities engage dual active sites, enabling the combination of both intermolecular benzylation and intramolecular arylation strategies that directs the formation of a diverse repository of cyclic structures. The introduction of transition-metal catalysis in cross-coupling transformations sparked a revolution in forging aryl–heteroatom bonds, culminating in the evolution of more potent methodologies for the synthesis of a wide spectrum of valuable compounds. Furthermore, the associated pharmaceutical and biological attributes of these cyclic structures augment their significance in medicinal chemistry research. This review aims to showcase the importance of this synthetic methodology and its far-reaching applications in synthesis. 1 Introduction 2 Synthesis of Five-Membered Rings 3 Synthesis of Six-Membered Rings 4 Synthesis of Seven-Membered Rings 5 Synthesis of Eight- and Nine-Membered Rings 6 Conclusion [ABSTRACT FROM AUTHOR]

The synthesis of 1,3-enyne has widespread appeal in organic synthesis due to their proven adaptability as intermediates in routes to compounds of significant biological and material interest. A variety of methods have been designed to formulate 1,3-enynes from diverse substrates, such as alkynes, 1,3-diynes, alkynyl-substituted cyclopropanes, and propargyl alcohols. This review covers the synthesis of 1,3-enynes utilizing the homo- and cross-coupling of alkynes, nucleophilic metal/acid-induced cyclopropane ring opening, and rearrangement/dehydration of propargyl alcohols. A key concern in procedures starting from alkynes and 1,3-diynes is the management of regio-, stereo-, and, where fitting, chemoselectivity. In contrast, in cyclopropyl ring opening nucleophile orientation determines the 1,3-enynes formed. Efficient methods for the broad and selective synthesis of 1,3-enynes are highlighted and specific examples are given to demonstrate the efficacy of these processes. 1 Introduction and Scope 2 Synthesis 2.1 Synthesis of 1,3-Enynes from Alkynes 2.1.1 Metal-Catalyzed Cross-Coupling/Additions of Alkynes with Alkenes or Vinyl or Aryl Halides 2.1.1.1 Palladium Catalysis 2.1.1.2 Rhodium Catalysis 2.1.1.3 Copper Catalysis 2.1.1.4 I ron Catalysis 2.1.1.5 Nickel Catalysis 2.1.1.6 Miscellaneous 2.2 Synthesis of Enynes from Propargyl Alcohols 2.3 Metal/Acid-Catalyzed Ring Opening of Cyclopropanes 3 Conclusion [ABSTRACT FROM AUTHOR]

An efficient method for N-arylation and N-N bond formation has been developed using an innoxious reaction medium, γ-valerolactone (GVL), as both a solvent and a ligand. The strategy involves utilizing CuI as a catalyst under conditions free of external ligands and bases. Various aldehyde and amine derivatives with different functional groups were investigated, resulting in the production of 2-aryl-2H-indazole compounds with yields ranging from 75% to 93%. This study highlights the effectiveness of GVL, a solvent derived from biomass, as a reaction medium and ligand in a multicomponent reaction. [ABSTRACT FROM AUTHOR]

In the present study, the aimed enamines 3 a–j were synthesized with yield ranging between 65 and 81 % by the reaction of 5‐((dimethylamino)methylene)‐1,3‐dimethylpyrimidine‐2,4,6(1H,3H,5H) ‐trione (2) with different amines at room temperature (25 °C). The structures of all synthesized compounds were characterized using different spectroscopic techniques. Molecular docking studies of the new compounds 3 a–j were carried out with human estrogen receptor (hER) enzyme to evaluate their activities as an effective drug molecules. It was investigated that the compounds 3 b, 3 e, 3 f and 3 j revealed the best binding affinities. All new compounds were evaluated towards antifungal activities, which conceded that the compound 3 e displayed a remarkable antifungal activity compared to the Fluconazole and Nystatin, and its Minimum Inhibitory Concentration (MIC) found to be 0.011 mM, while for Fluconazole the MIC value exhibited at 0.046 mM. Additionally, the toxicity for the new compounds found to be better than tamoxifen on MCF‐7 cells and among these molecules, the compound 3 e displayed the lowest IC50 value. [ABSTRACT FROM AUTHOR]

The p-toluene sulfonic acid (p-TSA) catalyzed cascade ring closing transformation has been executed for the preparation of novel spiroquinazolinone compounds 4 and 5 by the reaction between anthranilamide and cyclohexanone followed by subsequent acylation. These molecules were then examined against the inhibitory activity of Acetylcholineterase (AchE). The tested compounds revealed moderate anti-AChE activity of IC50 values ranging from 46.675 to 14.256 µM). The described results lead toward the development of compounds 4b and 5c having promising anti-AChE activities with IC50 values at the micromolar level. The docking study suggests that these hybrid spiroquinazolinone scaffold might facilitate the further development of investigated compounds as anti-Alzheimer agents. [ABSTRACT FROM AUTHOR]

The reductive cyclization of o-nitrobenzylidene amines under microwave conditions employing MoO2Cl2(dmf)2 as catalyst and Ph3P as reducing agent delivers 2-aryl-2H-indazoles with yields ranging from 61-92%. [ABSTRACT FROM AUTHOR]

Reactions between 1-nitroso-2-naphthols and α-functionalized ketones such as α-bromo-, α-chloro-, α-mesyloxy-, α-tosyloxy-, and α-hydroxy ketones under basic conditions delivered 2-substituted naphtho[1,2-d][1,3]oxazoles in a single synthetic operation. The product formation was accompanied by the unexpected loss of the C=O group from the α-functionalized ketones. With aryl bromides, allyl bromides, α-bromo diketones, α-bromo cyanides, α-bromoesters, and α-bromo ketoesters as substrates the formation of naphtho[1,2-d][1,3]oxazoles was also observed. The transformations were performed in 1,2-dichloroethane or acetonitrile under reflux and gave the corresponding naphthoxazoles with yields ranging between 52% and 85%. [ABSTRACT FROM AUTHOR]

2-(Anthracene-9-yl)-4,5-diphenyl-1 H -imidazole (ADPI) provides an intriguing molecular platform for developing organic fluorophores with diverse properties and fluorescence performances. However, derivatives of ADPI have not yet been well explored and extensive studies are warranted. To shed more light on this, we have synthesized a series of π-extended ADPIs through a concise synthetic route involving an efficient cross-condensation reaction followed by Pd-catalyzed Suzuki cross-coupling. The obtained compounds were subjected to X-ray single crystallographic analysis to understand their molecular conformational and solid-state packing properties. Furthermore, UV-Vis absorption and fluorescence spectroscopic analyses were conducted. Our experimental results have disclosed interesting solvatofluorochromic properties of these compounds which are useful for solvent polarity-sensitive applications. The presence of an amphoteric imidazolyl group in the ADPI derivatives also renders them sensitive fluorescence responses to strong protic acids ( e.g. , trifluoroacetic acid) as well as fluoride anion. It transpires that the fluorescence changes are dependent on the functional groups attached to the ADPI core, suggesting a bottom-up molecular tuning approach for development of fluorophores and chemosensors with diverse functions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A direct and operationally simple method for the regioselective synthesis of 2-aryl-substituted 2 H -indazoles is reported. The Pd-catalyzed reaction between easily available 2-bromobenzyl bromides and arylhydrazines employing Cs 2 CO 3 as the base and t -Bu 3 PHBF 4 as the ligand in DMSO at 120 °C in a sealed tube delivers the 2-substituted-2 H -indazoles in a single synthetic step with yields up to 79%. The new method is based on a regioselective intermolecular N -benzylation followed by intramolecular N -arylation and oxidation.