Synthesis of 2-arylamino-3-cyanoquinolines via a cascade reaction through a nitrilium intermediate

One-Pot Three-Component Reaction for the Synthesis of 3,4-Dihydroquinazolines and Quinazolin-4(3H)-ones

A highly efficient and straightforward one-pot synthesis of diversely substituted 3,4-dihydroquinazolines and quinazolin-4(3H)-ones has been achieved through a domino three-component assembly reaction of arenediazonium salts, nitriles, and bifunctional aniline derivatives. This new protocol involves three C-N bond formations through the initial formation of N-arylnitrilium intermediates from arenediazonium salts and nitriles, followed by the sequential nucleophilic addition and cyclization reactions with bifunctional anilines, leading to such N-heterocyclic compounds of biological and pharmacological importance. This method offers a simple, expedient, and robust approach with the use of amenable and easily accessible reactants/reagents under metal-free mild conditions, good functional group tolerance, and high efficiency. The synthetic applications were also demonstrated by derivatization of the products obtained from these processes and syntheses of a diverse range of valuable polycyclic N-heterocycles.

Recent advancement in the synthesis of quinoline derivatives via multicomponent reactions

The synthesis of quinoline derivatives through multicomponent reactions (MCRs) has emerged as an efficient and versatile strategy in organic synthesis. MCRs offer the advantage of constructing complex molecular architectures in a single step, utilising multiple starting materials in a convergent manner. This review provides an overview of recent advancements in the field of quinoline synthesis via MCRs. Various MCRs, such as the Povarov reaction, the Gewald reaction, and the Ugi reaction have been successfully employed for the synthesis of diverse quinoline scaffolds. These methodologies not only showcase high atom economy but also allow the incorporation of structural diversity into the final products. The versatility of MCRs enables the introduction of functional groups and substitution patterns tailored to specific applications. This review highlights the significance of quinoline derivatives in medicinal chemistry, materials science, and other interdisciplinary areas. The continuous innovation and development of novel MCR-based approaches for quinoline synthesis hold great promise for the rapid and efficient generation of valuable compounds with a wide range of biological and physicochemical properties.

Antibiofilm and Anti-Quorum-Sensing Activities of Novel Pyrazole and Pyrazolo[1,5-a]pyrimidine Derivatives as Carbonic Anhydrase I and II Inhibitors: Design, Synthesis, Radiosterilization, and Molecular Docking Studies

Nowadays, searching for new anti-infective agents with diverse mechanisms of action has become necessary. In this study, 16 pyrazole and pyrazolo[1,5-a]pyrimidine derivatives were synthesized and assessed for their preliminary antibacterial and antibiofilm activities. All these derivatives were initially screened for their antibacterial activity against six clinically isolated multidrug resistance by agar well-diffusion and broth microdilution methods. The initial screening presented significant antibacterial activity with a bactericidal effect for five compounds, namely 3a, 5a, 6, 9a, and 10a, compared with Erythromycin and Amikacin. These five derivatives were further evaluated for their antibiofilm activity against both S. aureus and P. aeruginosa, which showed strong biofilm-forming activity at their MICs by >60%. The SEM analysis confirmed the biofilm disruption in the presence of these derivatives. Furthermore, anti-QS activity was observed for the five hybrids at their sub-MICs, as indicated by the visible halo zone. In addition, the presence of the most active derivatives reduces the violacein production by CV026, confirming that these compounds yielded anti-QS activity. Furthermore, these compounds showed strong inhibitory action against human carbonic anhydrase (hCA-I and hCA-II) isoforms with IC50 values ranging between 92.34 and 168.84 nM and between 73.2 and 161.22 nM, respectively. Finally, radiosterilization, ADMET, and a docking simulation were performed.

Cyanoquinolines and Furo[3,4-b]quinolinones Formation via On-The-Spot 2,3-Functionalization of Quinolines with Cyanopropargylic Alcohols

A convenient approach to 2-(1-ethoxyalkoxy)-3-cyanoquinolines (in up to 50% yields) has been developed. The approach comprises functionalization of quinolines with acetals of cyanopropargylic alcohols (KOH/H₂O/MeCN, 55-60 °C) followed by their transformation to furo[3,4-b]quinolinones (in up to 98% yields) via the sequential removal of acetal protection and intramolecular cyclization/hydration (7% aqueous HCl, acetone, 20-25 °C).

Mesoporous HBeta zeolite obtained via zeolitic dissolution–recrystallization successive treatment for vapor-phase Doebner–Von Miller reaction to quinolines

Mesoporous HBeta zeolite was obtained via zeolitic dissolution–recrystallization successive treatment, and exhibited enhanced selectivity to Q, anti-alkylation ability and stability in the vapor-phase Doebner–Von Miller reaction.