Mini-Reviews in Organic Chemistry - Volume 21, Issue 1, 2024

The inefficiency of conventional water treatment methods in terms of removing micropollutants is prompting research into other technologies. Among these, the process of separation by nanofiltration membranes is particularly promising because of the low operating cost, rapid implementation of the system, high selectivity and easy integration with other treatment processes. Studies in this area are recent and there are many avenues for future research. This mini-review describes the main characteristics of the polymeric membranes used for nanofiltration and the various methods and polymer materials under investigation. At the end, we report the result of a survey conducted on the ScienceDirect, Scopus and Web of Science platforms using different keywords, to depict a global panorama of the current research involving polymeric nanofiltration membranes. The results revealed a particular dearth of published studies involving application of these membranes to remove micropollutants with endocrine disruptive action. Furthermore, research involving nanofiltration membranes utilizing calcium alginate is very recent. This study provides an overview of the investigation of polymeric nanofiltration membranes.

Coumarin and its derivatives are privileged heterocyclic motifs and important building blocks for developing the biologically active compound due to its significant role in the development of new drugs. As a result, many methodologies have been developed to synthesize this important class of compounds. However, some methods are associated with toxic and corrosive catalysts, longer reaction time, poor yield, less purity, and by-products along with the desired product. In order to minimize the utilization and generation of toxic organic substances, green synthetic methods are applied in this manner. Green chemistry methods cover a wide range of methods, including the application of ultrasound and microwaves, ionic liquids and deep eutectic solvents, solvent-free and catalyst-free synthesis, and mechanosynthesis. These green synthetic methods have successfully performed all typical condensation reactions for coumarin synthesis like Knoevenagel, Perkin, Kostanecki-Robinson, Pechmann, and Reformatsky reactions. Compared to conventional methods, these methods not only minimize the use and generation of harmful chemicals but also improve reaction efficiency in terms of product yields, purity, energy consumption, and post-synthetic procedures. Due to the implication of coumarin (2-oxo-2H-1-benzopyran) backbone as a biologically active ubiquitous fragment and the recent demands of reducing toxic solvents, catalysts, and energy consumption, this review summarized various green synthetic methods for coumarin synthesis. Moreover, researchers working on this coumarin scaffold synthesis can find handy information from this review on the green synthetic approaches to their synthesis.

Natural products are important from the researchers’ perspectives due to their importance and applicability. Polyhydroxylated pyrrolizidine alkaloids are sugar mimics and received a growing interest in the last few years. Australine is a naturally polyhydroxylated pyrrolizidine, which was isolated from the seeds of Castanospermum austral, and exhibits potent biological activities such as inhibited glycosidases, as well as anti-virus, and anti-HIV activities. Thus, there is a considerable deal of interest in the synthesis of these classes of compounds. Different synthetic strategies and methodologies for the preparation of Australine and its stereoisomers were considered.

As a member of heterocyclic compounds, indole possesses a diverse set of biological activities. Studies on the structure-activity relationship of 2-indolinones have shown that they are important bioactive compounds in the field of pharmaceutical chemistry. Isatin and structures bearing isatin scaffold are derivatives of indole, which have shown to be of biological and pharmacological significance. This review focuses on different ways of obtaining compounds containing isatin structure, considering both earlier and recent methods of synthesis. The syntheses given herein were grouped into three categories, syntheses using anilines as their starting substance, synthetic methods based on the oxidation of indoles, and finally, due to the extensive research going on 5-substituted isatins and their possible pharmacological efficacy, pathways for synthesizing 5-amino and 5-sulfamoylisatins were gathered to underline the importance of 2-indolinone and isatin derivatives as prospective therapeutic compounds in current and future drug discovery studies.

4H-Pyran is a well-known moiety that appears in various natural and synthetic products. These compounds include various biological activities like anti-hepatotoxic, antitumor, antiinflammatory, antioxidant, anti-spasmolytic, diuretic, estrogenic, anticoagulant, antifungal, antiviral, anti-helminthic, antimicrobial, hypothermal, anti-tubercular, anti-HIV, herbicidal, anticonvulsant and analgesic activity. This review has summarized an overview of general strategies that allow the design of 4H-pyran derivatives via catalyzed one-pot multicomponent reactions.

Background: Pyrazoline is a heterocyclic compound with five members, two nitrogen atoms in a circle, and one endocyclic bond. Pyrazoline is a popular electron-rich nitrogen carrier that combines exciting electronic properties with the potential for dynamic applications. Pyrazine derivatives have been synthesized using a variety of methods, all of which have shown to have a strong biological effect. Objective: The study of the biological activity of pyrazoline derivatives has been a fascinating field of pharmaceutical chemistry. Pyrazolines are used in a wide range of applications. The pyrazoline derivatives described in the literature between 2000 and 2021 were the focus of this study. Pyazolines have been discussed in terms of their introduction, general synthetic method, and anticancer potential in the current review. Conclusion: Pyrazolines are well-known heterocyclic compounds. Pyrazoline is a five-membered ring containing three carbon and two nitrogen atoms nearby. The synthesis of pyrazolines has been described using a variety of methods. Anticancer activity has been discovered in a number of pyrazoline derivatives, which encourages further research. The use of pyrazoline to treat cancer has piqued researchers' interest in learning more about this moiety.