Current Organic Chemistry - Volume 28, Issue 3, 2024

Tetrahydroquinoxalines are found in many biologically and pharmacologically active small molecules. In the past two decades, significant progress has been made in the development of novel synthetic routes for the preparation of biologically active tetrahydroquinoxalines and their derivatives. This synthetic review aims to provide a comprehensive overview of the advancements in the field of various synthetic strategies and methodologies employed for the synthesis of tetrahydroquinoxaline scaffolds during this period. The review emphasizes the diverse synthetic approaches employed, including cycloaddition reactions, condensation reactions, intramolecular cyclization reactions, ring expansion reactions, hydrogenation reactions, and other miscellaneous methods.

Inflammation is an intricate physiological reaction that has a vital function in the body's protection against detrimental stimuli. Nevertheless, uncontrolled inflammation may result in the development of long-term conditions, such as arthritis, cardiovascular disorders, and even cancer. Scientists are always searching for new medicinal substances that might efficiently regulate the inflammatory response. Due to its distinctive structure and an extensive array of chemical interactions, the pyrazine moiety has emerged as a viable foundational component for synthesising anti-inflammatory drugs. This review article examines the many methods used to use the potential of pyrazine moiety for its anti-inflammatory capabilities. The paper focuses on the latest progress in the development, creation, and assessment of pyrazine-based compounds, demonstrating their modes of action and links between their structure and activity. This review aims to provide a complete overview of the current knowledge on pyrazine-derived compounds with anti-inflammatory action by gathering and critically analysing the latest research results. Moreover, the essay explores the difficulties and possibilities in this area, which sets the stage for the logical development of advanced anti-inflammatory substances using the pyrazine pattern.

Quinolones are among the class of antibiotics that are used most frequently worldwide and are used for treating a variety of bacterial diseases in humans. Recent research has shown that new, improved analogues of quinolones are being used as anticancer, antifungal, antiviral and other antimicrobial agents. In an earlier review (Part 1), we discussed the synthesis and antibacterial activity of quinolones in detail. This review focuses on the detailed study of newly synthesized quinolone compounds and their biological activity in different dimensions.

Synthetic organic molecules are vital for human life, serving as medications, pesticides, dyes, and food additives. Organic synthesis provides routes for the production of these molecules. The traditional methods of organic synthesis require energy, solvents, time, and certain conditions based on the nature of the reactions. To address the issues associated with conventional processes, various environmentally friendly (green) methodologies have been developed. Catalysts are crucial in many chemical methods. Chemists aim to develop catalysts that are cost-effective, easy to recover, and can be synthesized with high catalytic activity and renewability. Natural montmorillonite clay is an ideal material for efficient catalysts since it satisfies all these requirements. This review focuses on the recent advances in the development of renewable nanocatalysts made from montmorillonite to be used for the synthesis of various organic compounds.

1,2-Dimethyl-3-methylsulfanylbenzene is the key intermediate of topramezone. This work designed a two-step continuous-flow device to synthesize 1,2-dimethyl-3- methylsulfanylbenzene via diazotization and methanethiolation. The results showed that compared with the batch process, the continuous-flow method greatly shortened the residence time to 1 minute, avoided the accumulation of large amounts of diazonium salts to reduce decomposition and increased the product yield to 91.7%. At the same time, the continuous- flow process improved the safety and efficiency of the reactions, saved reaction time and had good prospects for industrial application.

In this study, some new pyrazoline derivatives bearing cyano or nitro groups were synthesized. The structures of the compounds were characterized by IR, ¹H-NMR, ¹³C-NMR and elemental analysis data. The ABTS·⁺, DPPH·, CUPRAC and β-Carotene/linoleic acid assays were carried out to determine the antioxidant activity of the synthesized pyrazolines. Compound P14 showed higher antioxidant activity than the standard substance BHA with IC50 values of 1.71±0.31 μM and 0.29±0.04 μM in ABTS⁺ and β-carotene/linoleic acid assays, respectively. Compound P12 also exhibited higher antioxidant activities than BHA with an IC50 value of 0.36±0.14 μM in β-carotene/linoleic acid analysis. In activity studies of pyrazolines against cholinesterase (AChE and BChE), tyrosinase, α-amylase and α- glucosidase, compound P1 (IC50 = 39.51±3.80 μM) showed higher activity against α-amylase and compounds P5 and P12 displayed higher activity against α-glucosidase than acarbose with IC50 values of 14.09±0.62 and 83.26±2.57 μM, respectively. The drug-like properties such as Lipinski and Veber, bioavailability and toxicity risks of the synthesized compounds were also evaluated. The compounds were predicted to be compatible with Lipinski and Veber rules, have high bioavailability and low toxicity profiles. Moreover, molecular docking studies were performed to better understand the high activity of the compounds against a-amylase and a-glucosidase enzymes.