Current Organic Chemistry - Volume 27, Issue 9, 2023

Although less well known than their fully unsaturated analogues, dihydrotetrathiafulvalenes (dihydro-TTFs) has been of considerable recent interest as components of organic conducting materials. In this article, the various methods for their synthesis are reviewed and this is followed by a survey of their structure and properties, including those of charge transfer salts, and an account of their reactions.

Carbon dioxide (CO2) is regarded as an ideal C1 building block for the synthesis of value-added chemicals due to its low price, non-toxic, rich reserves, and recyclability. Organic electrosynthesis, using electricity as the driving force to avoid the use of toxic or expensive reducing agents, has become an efficient and environmentally friendly synthetic method and is widely used in the chemical conversion of CO2. In particular, the electrocarboxylation reaction of CO2 with a substrate containing a specific group, such as C=O and C=N, can be realized to synthesize α-hydroxy acids, amino acids, and their derivatives under mild reaction conditions by accurately adjusting the current or potential. In this review, we focus on the recent advances in the electrocarboxylation of CO2 with unsaturated substrates (including ketones, aldehydes, and imines) in the past five years, which we hope could stimulate further research on electrocarboxylation of CO2 with ketones, aldehydes, and imines and provide a reference for the application of such reactions in green organic electrosynthesis in the future.

Millions of deaths have been reported due to viral infections in medical history, and various viral infections are mentioned as the main cause of death. Although different types of research have been conducted to develop effective medication, there is a high demand to truly cure various viral infections. The resistance to the existence of antiviral drugs on the market is the main threat to human health, and an intrinsic demand to develop and synthesize new scaffolds is highly required to find less toxicity and high antiviral activity. Nitrogen-sulfur heterocyclic compounds have extensively exhibited efficient biological and pharmacological activity against viral species, and physicochemical and pharmacokinetic properties. In this microreview, recently developed nitrogen-sulfur heterocyclics and their performance with marked and selective antiviral activities are summarized. We hope this micro-review will help early scientists interested in the design of new compounds with selective and pronounced antiviral activities to identify and satisfy the necessary criteria for the further development of nitrogen-sulfur heterocyclic compounds.

Selective C-H bond functionalization of organic molecules has developed as an increasingly versatile platform that found wide applications in the synthesis of naturally occurring compounds, functional group modification, material sciences, and chemical and pharmaceutical industries. Apart from transition metal catalysis, which traditionally underwent a two-electron mechanism, a recent renascence of radical chemistry based on the hydrogen atom transfer (HAT) strategy has resulted in the rapid development of C-H bond functionalization. While many methodologies involving heteroatom-based HAT have been widely studied during the last decade, areas employing their carbon analogs were still challenging for chemists and remained less explored. Recent progress has been made to generate aryl radical species under relatively mild conditions, which can be utilized in the HAT step conveniently, and as a result, motivated the advancements of remote C(sp³)-H functionalization of various organic compounds, including amines, alcohols, amides and so on. This review will discuss the recent progresses in the functionalization of C-H bonds characterized by a key aryl HAT process, and, at the same time, some emphases have been laid on selective C-H functionalization catalyzed by photoredox chemistry.

Since the discovery of the new conversion, through intramolecular Pinner to Dimroth rearrangement to form a new skeleton product of dihydroquinazolinone in the normal reaction of Friendländer quinoline synthesis of o-aminonitriles and carbonyl compounds, systematic studies have shown that this conversion is a fast and efficient method for the synthesis of nitrogen-containing heterocyclic compounds, especially pyrimidinone derivatives. In 2008, we named this new transformation as a PDF conversion (a new conversion of dihydroquinolinone skeleton compounds formed from intramolecular Pinner to Dimroth rearrangement in the Friedländer quinoline synthesis). In this review, the research progress of PDF conversion is systematically summarized from the following aspects: the discovery of PDF conversion, the determination of the structure of new conversion products, the mechanism of PDF conversion, a new type of organic bifurcation reaction, controllable PDF conversion, the breakthrough of conventional PDF transformation forms, and the application of PDF conversion.

Infections that occur by protozoa are a chief universal issue for health, with wide endemicity in the involved areas. In the absence of a vaccine, there is an immediate requirement for efficient medications to replace those in common applications. However, their low effectiveness, lengthy treatment regimen, high poisoning, detrimental side effects of drugs and expensive prices require the need for superior medicine; these are all the factors that make leishmaniasis vaccines unavailable in the near future. Therefore, there is an immediate requirement to discover unique antileishmanial drugs with fine power and preferable remedial profile. Even though most of the medications are still derived from medicinal plant origins, the concern in higher plants as the origin of new bioactive natural compounds has been enhanced in recent years. The present study is a review of reports of naturally occurring diterpenoids extracted from plants and exhibiting anti-leishmaniasis activity. This review article refers to 25 plant species, their families, the portion used and the type of extract investigated. It also includes 88 diterpenoids extracted and identified from higher plant species, which are classified into chemically and structurally suitable groups. A number of recent reports and anti-leishmaniasis activities on natural compounds are discussed. This article provides a good overview of the future of leishmaniasis drug discovery.

Traditional Chinese medicine is an ancient system of wellness and health that has been used in almost all countries of the world, specially in Asia for thousands of years. The growth, development, final yield and chemical compounds of medicinal plants can be negatively influenced by different kinds of biotic and abiotic stresses. Abiotic stress signals are chemical stress (Mineral salts, heavy metal, aerosols, gaseous toxins, pesticides, and pollutants), salinity (salt), temperature (Heat, cold), radiation (Ionisation radiation, light and UV), water (Flooding, drought) and mechanical stress (Submergence, wind, soil movement). Relevant literature has been obtained using the keywords “Traditional Chinese Medicine”, “Abiotic Stress”, “Biotic Stress”, “Ginseng”, “Ginger”, “Goji berry”, “Astragalus”, “Ginkgo”, “Artemisia annua L.”, “LC-MS”, “GC-MS”, and “NMR” in scientific information, namely “Web of Science”, “PubMed”, “SciFinder”, and “Elsevier”. Some of the plants’ secondary metabolites under different growth conditions are Camptothecin (Camptotheca acuminata), Capsaicin (Capsicum sp.), Rosmarinic acid (Salvia miltiorrhiza), Codeine (Papaver somniferum), Resveratrol (Grapes, groundnut), Artemisinin (Artemesia annua), Allicin (Allium sativum), Rohitukine (Dysoxylum binectariferum), Stevioside (Stevia rebaudiana), Andrographolide (Andrographis paniculata), Saikosaponins (Bupleurum chinense), Sennosides (Cassia augustifolia), Rutin (Dimorphandra mollis), Valepotriates (Valeria species), Indole alkaloids (Catharanthus roseous), and Furanocoumarins (Bituminaria bituminosa). The aim of this article is a survey of active chemical compounds and metabolic changes of some of the most important medicinal plants in traditional Chinese medicine (TCM) in both abiotic and biotic stresses. Future research is needed to evaluate the effects of biotic and abiotic stresses on chemical compounds and active metabolites of medicinal plants specially traditional Chinese medicine, and more surveys on the roles of LC-MS, GC-MS and NMR techniques for a better understanding of chemical components of medicinal plants.