Letters in Organic Chemistry - Volume 21, Issue 4, 2024

Mannich bases have a distinct place in the field of medicinal and pharmaceutical chemistry. These are used as lead compounds for the synthesis of numerous heterocyclic compounds, which possess diverse biological activities and play pivotal roles. This review covers the latest literature and knowledge on Mannich bases derived from coumarin. In addition, this review also aims to provide a comprehensive overview of recent developments in medicinal chemistry and shed light on the biological activities and structure-activity relationship (SAR) of coumarin-based Mannich bases.

A five-membered heteroaromatic ring with two nitrogen atoms, pyrazole, is of immense significance. Pyrazole and its derivatives are well-known nitrogen-containing heterocyclic compounds that are significant in medicinal chemistry and have a variety of biological properties, according to a thorough analysis of this class of heterocyclic lead. This article summarises some biologically active, potent pyrazole hybrids and their structure-activity relationship for antimicrobial activity published by various researchers across the world. It is divided into two sections. The first part summarizes recent developments in pyrazole derivatives for various biological activities, such as anti-Alzheimer’s, antioxidant, anticancer, anti-inflammatory, and antiviral, while the second section focuses on a detailed substitution analysis of pyrazole with its hybrid, which is the structure-activity relationship needed for antimicrobial activity. The presence of pharmacological potential of pyrazole moiety has been demonstrated by the role of a nucleus in pharmacological agents from different therapeutic groups, such as the potent anti-inflammatory agent celecoxib, anti-obesity drug rimonabant, analgesic diphenamizole, H2-receptor agonist betazole, and antidepressant agent fezolamide. The design of new pyrazole derivatives has become an interesting research area due to their versatile nature and biological significance. Moreover, it has been observed that pyrazole in combination with another moiety has a strong potent antimicrobial effect.

Microbial infection is one of the major concerns for human health in the modern era. Condition is further worsening due to the development of resistance by the microbe against the available drugs. This problem can be overcome by synthesizing novel antimicrobial agents. Isatin is a promising moiety possessing antimicrobial activity. A number of isatin derivatives are present in the market for the treatment of microbial infection. In this review, we have tried to summarize isatin derivatives as antimicrobials, including numerous potent isatin analogs. The reported literature related to the development and application of isatin derivatives have been collected from electronic data bases like Science Direct, Google Scholar, and PubMed by using key words like “design, synthesis and evaluation”, “isatin derivatives,” and “indoldione analogues” and related combinations. It was identified that isatin derivatives play an essential role in drug discovery and development. In recent years, isatin and its derivatives have shown promising antibacterial and antiviral properties. This review aims to provide an overview of the current research on isatin potential applications. Studies have shown that isatin derivatives can effectively fight against various types of microorganisms, such as gram-negative and gram-positive bacteria. They also exhibit lower toxicity and better efficacy than standard antimicrobial agents. Moreover, isatin-based products have the potential to address the rising issue of antimicrobial resistance. The current work attempts to review such innovations, which may lead to the creation of novel therapeutic agents. More research is required to confirm their safety and effectiveness in clinical practice.

Pyrazine belongs to the 1, 4-diazines family, which is a significant class of heterocyclic compounds. Various pyrazine derivatives have been produced and successfully confirmed as medicines with various pharmacological activities like anti-inflammatory, antitubercular, anticancer, antibacterial, and neurological activity, with some of them becoming clinically utilized pharmaceuticals globally. This review includes a survey on pyrazine derivatives possessing different pharmacological activities. The class of pyrazine-based potential medications has grown rapidly in terms of both the absolute quantity of studied compounds and the range of various biological activities. Additionally, there is a lot of potential for this scaffold, which medicinal chemists ought to investigate for the creation of novel potential drug candidates.

In this study, a simple one-pot synthesis of acetamides from aromatic amines and acetonitrile in the presence of H2O and K2S2O8 is presented. The reaction proceeds in a mixed solvent (CH3CN: DMSO, 3:1) without using metals or toxic reagents. Various N-acetanilides are obtained with 53-91% yields. The method is selective for aromatic amines, with aliphatic amines remaining intact. This represents a new, efficient, and economical method for the synthesis of a range of acetamides.

Surfactants have great importance in biological and drug industries and the complexes of metallic soaps with various ligands are used in approximately every region of national economy. Therefore, our keen interest to study of degradation kinetics and biological importance of Cu (II) surfactants in non-aqueous and non-polar solvent benzene. Present research work has been initiated with synthesis, systematic study of structural elucidation, thermal degradation, kinetics and biocidal activities of copper (II) sesame-soap complexes with macrocyclic nitrogen and sulphur containing donar ligands like urea and thiourea. The thermal degradation of copper (II) sesame-soap complexes were carried out for analysis of degradation kinetics and estimation of kinetic and thermodynamic parameters using different methods at heating rate 10^oC min^-1. Copper (II) sesame-soap complexes of such ligands have also been analysed against Staphylococus aureus. This research work consolidates the synthesis of copper (II) sesame soap-urea and thiourea complexes by conventional methods and the structure of these complexes were assigned according to elemental analysis and molecular weight determinations. IR, NMR and ESR spectral studies have also been done to understand structural aspects. The anti-microbial activities of copper (II) sesame-soap urea and thiourea complexes have been evaluated by testing against Staphylococus aureus. The present research work includes information of thermal analysis using TGA technique to find out their kinetic and thermodynamic parameters by using diverse equations such as Coats-Redfern equation, Horowitz-Metzger equation, Broido equation, Piloyan–Novikova equation. Moreover, the results obtained from anti-microbial screening have been used to analyze the anti-microbial activities of copper (II) sesame-soap urea and thiourea complexes against gram-positive bacteria Staphylococus aureus. These results show that complexes of copper ion co-ordinated with different nitrogen, oxygen and sulphur containing ligands, are very important in the field of pharmaceutical chemistry due to its significant role in the inhibition activity. The study of these complexes concludes that the synthesized complexes were found to possess appreciable bactericidal properties at different concentrations because chelation increases the anti-microbial potency.

Caffeoyl spermidines are valuable alkaloids naturally existing in many plant species. These alkaloids are characterized as pharmacologically important ingredients of many plant extracts used in traditional medicines. Bis-caffeoylspermidine and bis-dihydrocaffeoylspermidine exhibit antioxidant, anti-inflammatory, and enzyme inhibition properties that make them valuable natural sources of safer therapeutic agents. However, the limited availability of these compounds in nature derives the attention of synthetic chemists. Therefore, we synthesized bis-caffeoylspermidine and bisdihydrocaffeoylspermidine using cheaper and commercially available starting materials in 97% and 86% overall yields, respectively. The synthetic scheme can be upgraded to the commercial-scale synthesis of these compounds.