Current Organic Chemistry - Volume 29, Issue 15, 2025

The review describes the oxidative addition of sulfonamides to allylic derivatives. The direction of the sulfonamidation reaction depends on various factors, such as the type of allylic substrate, solvent, oxidant, and the reactivity of the sulfonamide. Intramolecular cyclization of allyl sulfonamides is a simple method for obtaining nitrogen-containing heterocyclic compounds with diverse structures. Reactions between O-allylic substrates and sulfonamides in the presence of oxidizing agents can produce cyclic or linear amino ethers, which are valuable for the synthesis of heterocyclic biologically active compounds. N-allylic substances are excellent starting materials for the synthesis of N-heterocyclic compounds and linear products with two or three amino groups, providing ample opportunities for further functionalization. When allylsilanes are exposed to oxidizing conditions, they undergo desilylation, allowing for the introduction of an allylic group into reactions with sulfonamides, resulting in products free from Si-heteroatoms, based on a C3-allylic scaffold and sulfonamide nitrogen. The choice of reaction medium and oxidizing agent can significantly affect the course of the reaction, leading to the formation of different products. The main products include aziridines, pyrrolidines, piperazines, lactams, oxazolidines, amino ethers, amidines (imidazoline precursors), and products of aminohalogenetation. This review provides a comparative analysis of the reactivity of sulfonamides in oxidative addition reactions and considers the advantages and disadvantages of synthetic methods.

Molecular photoswitches represent a dynamic and ever-growing research area based on the ability of molecules to convert (switch) between cis-(Z) and trans-(E) isomers. Azobenzenes are the most popular and widely employed Z-E photoswitchable molecules in the development of photoresponsive, multifunctional smart materials for various applications. The promising avenues in this field include molecular fine-tuning of azobenzene-based photoswitches and the creation of single or dual-functional probes. This short overview highlights recent advances in the design of molecular photoswitches, particularly the molecular design strategies of azobenzene-based photoswitches with their structural and electronic features. Particular attention is paid to azoquinolines, which seem to be a promising alternative to azobenzenes in the design of novel multifunctional photoswitches with improved photochromic properties. Here, we have also developed the novel star-shaped multiazoquinoline photoswitch comprising individual azoquinoline-based photochromes connected to a central trisubstituted 1,3,5-triformylphloroglucinol core by quantum chemical calculations. This unique structure is favorable for independent Z-E isomerization of each azoquinoline-based photochrome within one macromolecule.

Various phenazine scaffolds are reputed for their significant biological activities. The majority of them can be obtained from natural sources. Other phenazine derivatives, especially benzo[a]phenazines, are found to possess immense biological efficacies, including antimicrobial, antifungal, anticancer, antileukemic, antitumor activities, etc. Constant efforts have been made to increase the biological efficacies by using fusing benzo[a]phenazine skeleton with the other biologically promising heterocycles. Among many others, benzo[a]phenazine annulated with pyran skeleton was found to exhibit a wide range of biological efficacies like antimalarial, anti-plasmodial, anticancer, antiangiogenic, anticancer activities, etc. These observations motivated us to synthesize some benzo[a]pyrano[2,3-c]phenazine derivatives under greener conditions by following multicomponent reaction strategies. In this study, we report a facile, straightforward, and environmentally benign high-yielding one-pot four-component reaction protocol for the preparation of a series of 3-amino-2-cyano-1-aryl/alkyl-1H-benzo[a]pyrano[2,3-c]phenazines from the reactions of 2-hydroxy-1,4-naphthaquinone, o-phenylenediamines, malononitrile, and aromatic/aliphatic aldehydes using DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) as an efficient organocatalyst in aqueous ethanol under refluxed conditions. Moreover, under the same optimized reaction conditions, a number of spiro[benzo[a]pyrano[2,3-c]phenazine-1,3'-indoline] derivatives were also synthesized in good yields from one-pot four-component reactions of 2-hydroxy-1,4-naphthaquinone, o-phenylenediamines, malononitrile, and isatin or substituted isatins.

Pyridines/Dihydropyridines is a basic 6-membered organic aza-heterocyclic compound that has garnered the attention of many researchers in recent times. These molecules have been reported with a diverse range of pharmacological activities like anti-coagulant, antileishmanial and anti-trypanosomal, antitubercular agents, anti-microbial, antioxidant, HIV-1 protease inhibitors, anti-cancer, cardiovascular disease, etc. This review article focuses on different protocols for the Hantzsch reaction using acid catalysts, metal catalysts, and no catalysts for the synthesis of pyridine derivatives. The structure-activity relationship in relation to other biological activities of various pyridine-containing drugs and their interaction with different targets (receptors) has also been highlighted to provide a good understanding to researchers for future research on pyridines.

Selectfluor, bis(tetrafluoroborate)[1-chloromethyl-4-fluoro-1,4-diazoniabicyclo-[2.2.2] octane] is an extraordinarily stable solid with exceptional properties, such as strong solubility and stability in polar solvents, minimal toxicity, excellent thermal stability, and utility as an oxidant. One of the electrophilic fluorinating compounds that is most frequently employed in fluorination reactions is Selectfluor. In this mini-review, we have briefly updated the various applications of Selectfluor in organic synthesis, particularly in C-C, C-heteroatom and heteroatom-heteroatom bond formation reactions from mid-2020 to date. In addition to these, Selectfluor found useful in heterocyclic ring formations, demethylation, deoxygenation and other miscellaneous reactions. The results that have been published thus far show how extraordinarily promising Selectfluor-mediated organic molecule skeleton assembly events can be. Visible light, electrochemical, and nano-based reactions still have a lot of room for growth and application, despite the noteworthy advances in these domains. The compilation is subdivided based on the type of reaction/function of Selectfluor organic transformation.

The field of biocatalysis has blossomed exponentially over the past decades and revolutionized chemical synthesis, providing greener and sustainable methods for preparing numerous organic molecules at bench and industrial scales and in high stereoselective mode for the chiral ones. However, despite the tremendous progress, researchers still have room to contribute significantly to the field, especially in the valorization of agro-industrial waste to boost the circular (bio) economy. This review summarizes the use of lipases, the most versatile biocatalyst, in enantioselective transesterification reactions. The emphasis is on biobased materials involved in lipase-catalyzed enantioselective transesterification, such as agro-industrial waste for lipases production (isolation source and growth), the use of biobased solvents, renewable acyl donors and biobased materials for enzyme immobilization. We also discuss the perspectives of how to connect the high demand for more robust enzymes and the development of cost-effectiveness enantioselective methods, as well as the challenges to achieving a circular economy.