Research on heterocyclic compounds is an area of continuous focus, capturing the interest of both synthetic and natural product chemists. Indazoles are one of the rare heterocycles that are available in nature. Indazole and its derivatives are one of the most important classes of heterocycles in pharmacological molecules. The structurally different indazole motifs, with impressive bioactivity, have drawn increasing attention from medicinal chemists in recent years for the continuous development of novel drug moieties. Thus, knowledge of the biological activities and synthetic pathways of indazole scaffolds is essential to enhancing further developments in the number of indazole-based lead molecules. The goal of the present review is to highlight information on the biological properties of some existing indazole-based drugs and activities of novel bioactive indazole compounds in clinical trails, with specific attention to the most recent advances in various synthetic strategies towards indazole and its derivatives over the past 7 years (2017–2024). Moreover, we discuss the substrate tolerance and mechanistic insights for most of the summarized synthetic protocols.Graphical

Computational organic chemistry has become a valuable tool in the field of bioorthogonal chemistry, offering insights and aiding in the progression of this branch of chemistry. In this review, I present an overview of computational work in this field, including an exploration of both the primary computational analysis methods used and their application in the main areas of bioorthogonal chemistry: (3 + 2) and [4 + 2] cycloadditions. In the context of (3 + 2) cycloadditions, detailed studies of electronic effects have informed the evolution of cycloalkyne/1,3-dipole cycloadditions. Through computational techniques, researchers have found ways to adjust the electronic structure via hyperconjugation to enhance reactions without compromising stability. For [4 + 2] cycloadditions, methods such as distortion/interaction analysis and energy decomposition analysis have been beneficial, leading to the development of bioorthogonal reactants with improved reactivity and the creation of orthogonal reaction pairs. To conclude, I touch upon the emerging fields of cheminformatics and machine learning, which promise to play a role in future reaction discovery and optimization.

Silicone surfactants have garnered significant research attention owing to their superior properties, such as wettability, ductility, and permeability. Small-molecular silicone surfactants with simple molecular structures outperform polymeric silicone surfactants in terms of surface activity, emulsification, wetting, foaming, and other areas. Moreover, silicone surfactants with small molecules exhibit a diverse and rich molecular structure. This review discusses various synthetic routes for the synthesis of different classes of surfactants, including single-chain, "umbrella" structure, double chain, bolaform, Gemini, and stimulus-responsive surfactants. The fundamental surface/interface properties of the synthesized surfactants are also highlighted. Additionally, these surfactants have demonstrated enormous potential in agricultural synergism, drug delivery, mineral flotation, enhanced oil recovery, separation, and extraction, and foam fire-fighting.

The kinetically inert, six coordinated, octahedral Pt(IV) complexes are termed dual-, triple-, or multi-action prodrugs based on the nature of the axially substituted ligands. These ligands are either inert or biologically active, where the nature of these axial ligands provides additional stability, synergistic biological activity or cell-targeting ability. There are many literature reports from each of these classes, mentioning the varied nature of these axial ligands. The ligands comprise drug molecules such as chlorambucil, doxorubicin, valproic acid, ethacrynic acid, biologically active chalcone, coumarin, combretastatin, non-steroidal anti-inflammatory drugs (NSAIDs) and many more, potentiating the anti-proliferative profile or reducing the side effects associated with cisplatin therapy. The targeting and non-targeting nature of these moieties exert additive or synergistic effects on the anti-cancer activity of Pt(II) moieties. Herein, we discuss the effects of these axially oriented ligands and the changes in the non-leaving am(m)ine groups and in the leaving groups on the biological activity. In this review, we have presented the latest developments in the field of Pt(IV) complexes that display promising activity with a reduced resistance profile. We have discussed the structure activity relationship (SAR) and the effects of the ligands on the biological activity of Pt(IV) complexes with cisplatin, oxaliplatin, carboplatin and the Pt core other than approved drugs. This literature work will help researchers to get an idea about Pt(IV) complexes that have been classified based on the aspects of their biological activity.

Metal-based catalysts, encompassing both homogeneous and heterogeneous types, play a vital role in the modern chemical industry. Heterogeneous metal-based catalysts usually possess more varied catalytically active centers than homogeneous catalysts, making it challenging to regulate their catalytic performance. In contrast, homogeneous catalysts have defined active-site structures, and their performance can be easily adjusted by modifying the ligand. These characteristics lead to remarkable conceptual and technical differences between homogeneous and heterogeneous catalysts. As a recently emerging class of catalytic material, single-atom catalysts (SACs) have become one of the most active new frontiers in the catalysis field and show great potential to bridge homogeneous and heterogeneous catalytic processes. This review documents a brief introduction to SACs and their role in a range of reactions involving single-atom catalysis. To fully understand process-structure-property relationships of single-atom catalysis in chemical reactions, active sites or coordination structure and performance regulation strategies (e.g., tuning chemical and physical environment of single atoms) of SACs are comprehensively summarized. Furthermore, we discuss the application limitations, development trends and future challenges of single-atom catalysis and present a perspective on further constructing a highly efficient (e.g., activity, selectivity and stability), single-atom catalytic system for a broader scope of reactions.

Photochromic compounds of the spiropyran family have two main isomers capable of inter-switching with UV or visible light. In the current review, we discuss recent advances in the synthesis, investigation of properties, and applications of spiropyran derivatives. Spiropyrans of the indoline series are in focus as the most promising representatives of multi-sensitive spirocyclic compounds, which can be switched by a number of external stimuli, including light, temperature, pH, presence of metal ions, and mechanical stress. Particular attention is paid to the structural features of molecules, their influence on photochromic properties, and the reactions taking place during isomerization, as the understanding of the structure-property relationships will rationalize the synthesis of compounds with predetermined characteristics. The main prospects for applications of spiropyrans in such fields as smart material production, molecular electronics and nanomachinery, sensing of environmental and biological molecules, and photopharmacology are also discussed.

Coumarins (2H-1-benzopyran-2-ones) are an important group of biological heterocyclic compounds present in various parts of many plant species, encompassing an array of biological and pharmaceutical activities. In view of the importance of coumarins in heterocyclic chemistry and biological sciences and recent advances in the design of magnetic nanocatalysts, we present herein recent developments pertaining to their synthesis exclusively using magnetic nanoparticles, which can be retrieved easily and thus conform to the tenets of greener synthesis. The preparation of various types of coumarins such as Pechmann-based coumarins, bis coumarins, pyranocoumarins, and coumarin derivatives bearing amine moiety, linked to nicotinonitriles, N-coumarin-2-furanone, and pyrrole-linked chromene derivatives using nanocatalysts with a Fe3O4 core are described. This review covers the synthetic developments in the recent years 2012-2021 and focuses entirely on the synthesis of coumarins in the presence of magnetic nanocatalysts using greener approaches such as solvent-free conditions or deploying alternative activation methods, namely microwave or ultrasound irradiation.

Water collection from moisture in air, i.e., atmospheric water harvesting, is an urgent future need for society. It can be used for water production everywhere and anytime as an alternative water source in remote areas. However, water harvesting and collection usually relies on desalination, fog, and dewing harvesting, which are energy intensive. In this respect, metal-organic frameworks (MOFs) have broad applicability for water harvesting in water-scarce areas; therefore, the current discussion focuses on this approach. Furthermore, recent progress on MOFs for moisture harvesters is critically discussed. In addition, the design, operation, and water harvesting mechanisms of MOFs are studied. Finally, we discuss critical points for future research for the design of new MOFs as moisture harvesters for use in practical applications. MOF adsorbents offer excellent operating capacity in various temperature and pressure ranges. Rational water harvesters can thus be developed by adjusting structural properties such as the porosity, functionalities, and metal centers, thereby enabling new devices to produce water even in remote areas.

The Diels-Alder reaction (DAR) is found in myriad applications in organic synthesis and medicinal chemistry for drug development, as it is the method of choice for the expedient synthesis of complex natural compounds and innovative materials including nanomaterials, graphene expanses, and polymeric nanofibers. Furthermore, the greatest focus of attention of DARs is on the consistent reaction procedure with stimulus yields by highly stereo- and regioselective mechanistic pathways. Therefore, the present review is intended to summarize conventional solvent-free (SF) DARs for the expedient synthesis of heterocyclic compounds and materials. In particular, this review deals with the DARs of mechanochemical grinding, catalysis (including stereoselective catalysts), thermal, and electromagnetic radiation (such as microwave [MW], infrared [IR], and ultraviolet [UV] irradiation) in SF procedures. Therefore, this comprehensive review validates the application of DARs to pharmaceutical innovations and biorenewable materials through consistent synthetic approaches.

Directed transformation of available natural compounds with native biological activity is a promising area of research in organic and medicinal chemistry aimed at finding effective drug substances. The number of scientific publications devoted to the transformation of natural compounds and investigations of their pharmacological properties, in particular, monoterpenes and their nearest derivatives, increases every year. At the same time, the chemistry of nitrogen-containing heterocyclic compounds has been actively developed since the 1950s after the news that the benzimidazole core is an integral part of the structure of vitamin B12. At the time of writing this review, the data on chemical modifications of monoterpenes and their nearest derivatives leading to formation of compounds with a nitrogen-containing heterocycle core have not been summarized and systematized in terms of chemical transformations. In this review, we tried to summarize the literature data on the preparation and properties of nitrogen-containing heterocyclic compounds synthesized from monoterpenes/monoterpenoids and their nearest derivatives for the period from 2000 to 2021.