Design and syntheses of some new quinoxaline derivatives containing pyrazoline residue as potential antimicrobial agents

Synthesis of a Series of Quinoxaline Derivatives and Their Antibacterial Effectiveness Against Pathogenic Bacteria

The pharmacological importance of quinoxaline derivatives in antibacterial research is well recognized. This study focuses on the synthesis of new 2,3‐dichloroquinoxaline derivatives containing thioether/ether groups to explore their potential as potent antibacterial agents against various pathogenic bacteria. Most of the compounds exhibited significant antibacterial properties comparable to the standard drug chlorhexidine (CHX). The derivatives of 2‐chloro‐3‐(arylthiol)quinoxaline demonstrated efficacy against Escherichia coli with minimum inhibitory concentrations (MIC) of 2.5 mg/mL and minimum bactericidal concentrations (MBC) of 2.5 to 5.0 mg/mL. These derivatives also showed similar sensitivity to Bacillus pumilus. In addition, molecular docking simulations were performed to investigate the interaction between the synthesized compounds and the DNA gyrase protein (PDB ID: 1KZN), a target for antibiotics. Among the synthesized compounds, 2,3‐bis(3‐nitrophenoxy)quinoxaline exhibited the most favourable docking score of −8.36 kcal/mol, with a binding affinity comparable to that of the reference ligand clorobiocin (−9.3 kcal/mol).

Diverse Pharmacological Potential of different Substituted Pyrazole Derivatives

The chemistry of heterocyclic compounds has been a topic of research interest. Some five-membered heterocyclic compounds have been the subject of extensive research due to their different types of pharmacological effects. The five-membered nitrogen-containing heterocyclic compounds pyrazole, pyrazoline, and pyrazolone derivatives have a lot of interest in the fields of medical and agricultural chemistry due to their diverse spectrum of therapeutic activities. Various substituted pyrazole, pyrazoline, and pyrazolone compounds exhibited diverse pharmacological effects like Anti-microbial, anti-inflammatory, anti-tubercular, anti-fungal, anti-malarial, anti-diabetic, diuretic, anti-depressant, anticonvulsant, antioxidant, anti-leishmanial, antidiabetic, and antiviral, etc. In recent decades, the synthesis of numerous pyrazole, pyrazoline, and pyrazolone derivatives by different synthetic methods as well as research into their chemical and biological behavior have become more important. This review focuses on synthetic methods of the pyrazole, pyrazoline, and pyrazolone derivatives, which have significant biological properties and a variety of applications.

Acid-Promoted Direct C-H Carbamoylation at the C-3 Position of Quinoxalin-2(1H)-ones with Isocyanide in Water

Described herein is a concise and practical direct amidation at the C-3 position of quinoxalin-2(1H)-ones through an acid-promoted carbamoylation with isocyanide in water. In this conversion, environmentally friendly water and commercial inexpensive isocyanide were used as a solvent and carbamoylation reagent, respectively. This study not only provides a green and efficient strategy for the construction of 3-carbamoylquinoxalin-2(1H)-one derivatives that can be applied to the synthesis of druglike structures but also expands the application of isocyanide in organic chemistry.

Design, synthesis, and molecular docking studies of novel pomalidomide-based PROTACs as potential anti-cancer agents targeting EGFRWT and EGFRT790M

A new class of EGFR PROTACs based on pomalidomide was developed, synthesised, and tested for their cytotoxic activity against a panel of human cancer cells. Compounds 15–21 were showed to be more effective against the four tested cell lines than erlotinib. In particular, compound 16 was found to be the most potent counterpart as it was 5.55, 4.34, 5.04, and 7.18 times more active than erlotinib against MCF-7, HepG-2, HCT-116, and A549 cells, respectively. Compound 15 was revealed to be more active than doxorubicin against the four tested cell lines. Furthermore, the most potent cytotoxic compounds were studied further for their kinase inhibitory effects against EGFR^WT and EGFR^T790M using HTRF test. Compound 16 showed to be the most effective against both kinds of EGFR, with IC₅₀ values of 0.10 and 4.02 µM, respectively. Compound 16 could effectively degrade EGFR protein through ubiquitination (D_max = 96%) at 72 h in the tested cells.