Current Organic Chemistry - Volume 29, Issue 9, 2025

Novel bispidine skeleton has been extensively designed as bifunctional chelators (BFCs) for their special stereochemical structure and variable dentate numbers. Bispidine-based ligands (BBLs) as BFCs generally integrate the benefits of conventional acyclic and macrocyclic BFCs, demonstrating exceptional radiolabeling kinetics, thermodynamic stability and kinetic inertness for their metal complexes. The accessible inherent spatial asymmetry in bispidine skeleton is well-suited for Jahn-Teller active metal ions, notably Cu(II). Currently, BBLs have already been studied to coordinate with radionuclides such as ⁵²Mn, ^64/67Cu, ⁶⁸Ga, ¹¹¹In, ¹³³La, ¹⁷⁷Lu, ²¹²Pb, ^212/213Bi, and ²²⁵Ac for radiopharmaceuticals application. Among them, the ⁶⁴Cu, ⁵²Mn, ¹¹¹In, ¹⁷⁷Lu, and ²²⁵Ac complexes with BBLs have particularly made significant research progress. In this review, we introduce the synthesis of BBLs and their applications in chelating the above five metallic radionuclides for the development of radiopharmaceuticals are discussed.

Under the broad domain of multimetallic catalysis, the utilisation of two transition metals (either homometallic or heterometallic) as catalysts in a cooperative way to enhance reactivity and promote higher stereoselectivity and versatility has witnessed remarkable advancements in organic synthesis in the last two decades. This review attempts to provide an account of the development in the recent past to its progress now in this area, highlighting the importance of simultaneous catalytic cycles in the mechanistic pathway and optimal reaction conditions for organic transformations leading to building blocks of importance in biology and pharmaceutical applications. The reactions presented here include, among others, C-H activation, reductive cross-coupling, allenylation, tandem isomerisation-allylation, heteroarylation, and asymmetric synthesis.

Heterocyclic compounds with a pyridine structure are important in organic chemistry because they are found in many pharmaceuticals, agrochemicals, and natural substances. Traditional methods to create pyridines use harsh conditions and toxic chemicals, which can be harmful to the environment and human health. Recently, there has been interest in using ionic liquids (ILs) as a sustainable alternative for these reactions. ILs have low melting points and don't evaporate easily, making them environmentally friendly. They can act as both solvents and catalysts, and their properties can be adjusted by changing their components, allowing for better control over reactions. Advancements have shown that ILs can improve the efficiency, yield, and selectivity of pyridine synthesis. They enable one-pot multicomponent responses, reducing the need for multiple steps and minimizing waste. ILs can also lead to milder reaction conditions, decreasing energy use and hazardous by-products. Their recyclability supports cost-effectiveness and green chemistry principles. This review highlights recent progress in using ILs for pyridine synthesis, showing their advantages over traditional methods. Benefits include better yields, improved efficiency, enhanced selectivity, and the ability to perform complex reactions in one step. By exploring the role of ILs in pyridine synthesis, this review contributes to the development of sustainable and eco-friendly synthetic methods.

Indoles are critical in natural amalgamation for their flexible jobs in drugs, regular items, and material science, exhibiting huge pharmacological and compound reactivity. Due to their versatility and high reactivity, nitroalkenes are essential electrophilic partners in organic synthesis. While indoles and nitroalkenes are used in both Michael addition and Friedel-Crafts alkylation for producing carbon-carbon bonds, the catalyst types and reactions involved are different. Michael addition employs conjugate addition, whereas Friedel-Crafts alkylation employs electrophilic aromatic substitution. Each technique has a different level of selectivity and distinct synthetic applications. This review aims to examine the advancements and persistent challenges in catalysis, focusing on the comparative methodologies of Friedel-Crafts alkylation and Michael addition involving indoles and nitroalkenes. Emphasizing green chemistry principles, it discusses the potential for sustainable and efficient synthetic processes through the use of innovative catalysts, including photocatalysis and biocatalysis. The integration of computational studies and interdisciplinary collaboration is essential for developing economically viable and environmentally responsible chemical synthesis, ultimately contributing to the creation of advanced materials and pharmaceuticals.

Imidazopyridine holds significance as a crucial fused bicyclic heterocycle within the realm of medicinal chemistry, being acknowledged as a “privileged scaffold” owing to its extensive utility. Numerous methodologies for the synthesis of imidazo[1,2-a]pyridines have been documented, with a considerable focus on strategies aimed at functionalizing these compounds. This study aimed to explore the potential of novel imidazo[1,2-a] pyridine derivatives as agents against drug-resistant Mycobacterium tuberculosis, which poses significant challenges in tuberculosis (TB) treatment. The research involved the synthesis of substituted imidazo[1,2-a]pyridine derivatives using site identification and molecular docking techniques. Characterization of the synthesized compounds was carried out using FT-IR, LC-MS, ¹H NMR, and ¹³C NMR analysis. Compounds 6a and 6k showed good anti-TB activity against the H37Rv strain of Mycobacterium tuberculosis, with MIC values of 0.6 μM and 0.9 μM, respectively, which were comparable with the standard drug isoniazid. These findings suggest that imidazo[1,2-a]pyridine derivatives, especially compounds 6a and 6k, have potential as agents against drug-resistant TB, providing valuable insights for ongoing efforts in developing effective TB treatments.