Current Organic Chemistry - Volume 28, Issue 11, 2024

Azepine is a privileged nitrogen-containing ring that has been found to display a wide range of biological activities. Azepine is a valuable skeleton in designing novel compounds in medicinal chemistry due to its interesting chemical and biological properties. The study on the synthesis of this ring system engenders a fascinating area of research owing to its potential to form an active pharmacophore for De Novo exploration. In this study, conventional and domino results were compared to access the diverse set of azepines in high yield. The domino approach has revolutionized the way through which the previously impossible yet significant transformations could be conceptualized, allowing the construction of difficult materials in one step. The aim of the present mini-review is to highlight the importance of the one-pot domino reaction for the synthesis of condensed azepines. This review also presents research on this subject from the past two decades.

2,3-Dihydrobenzofuran and coumaranone are readily available in numerous naturally occurring compounds. They mostly exist in plenty of food plants and medicinal plants. Such compounds constitute a series of flavor components and bioactive molecules. Their preparation has been an attractive field of research. In the past few decades, great efforts have been made in the preparation of the 2,3-dihydrobenzofuran structure through both metal-catalyzed and organocatalyzed ways. Visible light-promoted reactions sprang up in the early 21st century and represent a green manner of transformations. Under the irradiation of visible light, radicals could be generated under milder conditions. Thus, visible lightpromoted reactions spread widely in the field of chemical synthesis. In recent years, visible light-promoted preparation of 2,3-dihydrobenzofuran and coumaranone has been developed by different groups, including both intramolecular and intermolecular reactions. The benign reaction conditions allow better functional group-tolerance and lead to diverse structures. Several reviews on the synthesis of 2,3- dihydrobenzofuran have been reported. However, visible light-promoted approaches to such structures have not been well reviewed. Our review will cover the literature that has been reported on the discovery of 2,3- dihydrobenzofuran in food and visible light-promoted preparation of 2,3-dihydrobenzofuran, attempting to summarize the existing methods and provide guidance to the chemists on the present challenges.

A natural and renewable substrate for the synthesis of high-performance macromolecules is polysaccharides. Grafting with the use of microwaves of synthetic polymers onto natural polysaccharides is a common, adaptable, and practical method of creating materials based on polysaccharides. It eliminates all drawbacks of the traditional grafting technique, including the need for hazardous solvents and longer reaction times. Grafting yield is also increased by microwave irradiation. In fact, the employment of microwaves in polysaccharide grafting modification for diverse applications has been prompted by the growing interest in clean and environment-friendly chemistry. Furthermore, compared with their traditionally synthesized counterparts, microwave-synthesized polysaccharide copolymers frequently have greater characteristics for commercial exploitation. Moreover, for many traditional grafting processes, the necessity for an inert environment is an additional drawback, which can be overcome by microwave grafting techniques. This study focuses on the current use of microwave heating in polysaccharide grafting modifications and its further use in pharmaceutical formulations.

Research on novel discotic molecules, which consist of a rigid core with flexible peripheral chains, has gained much attention due to their crucial role as organic photovoltaic materials, organic field-effect transistors, and semiconductors for photocurrent generation, as well as the possibility of their other optoelectronic applications. This review article describes the developments in fundamental design ideas and synthetic approaches of porphyrin- based meso and beta-substituted liquid crystals. In addition, the current review highlights the various structural alterations made by the researchers in the field of porphyrinbased mesogens and changes in properties, both for materials intended for commercially successful liquid crystal displays, including other applications, and for more basic purposes of demonstrating structure-property relationships.

Polysubstituted pyridine derivatives were produced with high to excellent yields in the presence of nitrogen-doped graphene (NDG) as a dual acid-based catalyst. NDG efficiently catalyzes the multicomponent reaction between arylaldehydes, diethyl-acetylene dicarboxylates, malononitrile, and ammonium acetate under solvent-free conditions at 80°C to afford the polysubstituted pyridines in short reaction times. The structures of the synthesized pyridines were established by Ft-IR, ¹H, and ¹³C NMR spectroscopic analysis. The advantages of this method include the in-situ oxidation of prepared 1,4-dihydropyridines, one-pot procedure, solventless system, operational simplicity, and no column chromatography. Additionally, neither toxic solvents nor catalysts are needed, and the procedure can be very reliable among the reported methodologies. The yields and reaction times in the presence of four times recycled catalyst are in comparable to the fresh catalyst.