Current Organic Chemistry - Volume 30, Issue 1, 2026

The microwave-assisted synthesis of 1,3,5-triaizne (2,4,6-trichloro-1,3,5-triazine), also known as TCT analogs, is described in this review article. The reactions of TCT with different compounds that have amine functional groups or hydroxy-substituted functional groups under microwave irradiation to produce the triazine derivatives are the main topic of this review article. The microwave irradiation technique has countless benefits over the heating method, such as fast reactions, reduced reaction time from hours to minutes, fewer by-products, improved or high yields, wide temperature instability range, regioselective products, and greater energy efficiency.

Abrupt increase in the cancerous cells, conventional therapies, including radiation and chemotherapy, often exhibit limited efficacy due to the heterogeneous nature of tumours, which can result in collateral damage to normal cells, severe haematological toxicities, and the development of drug resistance, ultimately compromising treatment outcomes and patient compliance. On the other hand, naturally sourced heterocyclic compounds can trigger functional versatility and play critical roles in various biochemical processes within living cells, enhancing their potential as therapeutic leads. Their ability to modulate multiple oncogenic signalling pathways influences key processes such as apoptosis, cell proliferation, migration, angiogenesis, and metastasis, thereby positioning them as promising candidates for improving chemotherapy efficacy, especially in resistant cases. With the rising costs of conventional treatments and the increasing cancer burden, there is an urgent demand for low-cost and sustainable alternatives. In view of that, natural heterocyclic bioactive compounds pave substantial advantages, including a broad chemical range with minimal toxicity and enhanced safety, making them compelling substitutes for synthetic drugs. This review illuminates the molecular mechanisms underlying the anti-cancer properties of significant heterocyclic structures from natural sources, emphasizing their potential to advance therapeutic strategies and emerging future clinical applications over the period of fifteen years.

Heterocyclic rings containing heteroatoms at the 1,4-position and fused to a benzene ring are essential in medicinal chemistry due to their wide range of therapeutic and biological properties. Among them, 1,4-benzoxazine derivatives are distinguished by their heterocyclic structure, characterized by the fusion of a benzene ring with an oxazine ring with oxygen and nitrogen atoms in 1,4-positions. The latter heterocyclic motif gives these compounds great versatility, improving their chemical stability and promoting specific interactions with various biological targets. These compounds possess various pharmacological properties, including antifungal, antistrophic, antihypertensive, anti-Parkinson, anti-Alzheimer, anti-Huntington, antibacterial, and antirheumatic activities. Various synthetic methods have been developed to obtain 1,4-benzoxazine derivatives. These methods typically involve the condensation of 2-aminophenol with α(β)-dicarbonyl and α-halocarbonyl compounds, alkyl 2-halomalonates, and diethyl fumarate. This review focuses on synthetic approaches and methods used to synthesize 1,4-benzoxazine derivatives. It examines a range of proven pharmacological applications of these derivatives described in the literature from 1960 to 2024. The aim is to provide valuable insights for medicinal and organic chemistry researchers, offering guidance on developing and designing novel 1,4-benzoxazine derivatives.

Thiocrown ethers, thiocalixarenes, and thiocyclodextrins, as important host macrocycles, have been synthesized as crown ether, calixarene, and cyclodextrin derivatives, respectively. They have shown special properties compared with their prototypes. Hemicucurbiturils, as a subset of cucurbiturils, are yet to have their thio-derivatives. In this article, methods for the synthesis of hybrid thiohemicucurbiturils were proposed, and several hybrid thiohemicucurbiturils were formed. The mono ethylene thiourea-substituted hemicucurbituril was formed by simply mixing ethylene thiourea and ethylene urea with formaldehyde in an HCl aqueous solution. The synthesis of more ethylene thioureas-substituted hemicucurbituril by acid-catalyzed conversion of an ethylene thiourea-substituted hemicucurbituril has been presented, which differs from the traditional method for synthesizing hemicucurbituril derivatives. These methods provide alternatives for the synthesis of novel hybrid hemicucurbiturils with more complex structures.

Ionic compounds of tetradecachlorocyclohexasilane, a critical precursor for cyclohexasilane and its derivatives, have been synthesized using various methods. However, these approaches are often hindered by low yields, high costs, and environmental concerns. In this study, a novel perchlorinated cyclohexasilane salt, [(i-Pr2EtNH)2Cl⁺]2[Si6Cl14^2-], was synthesized by the cyclization of trichlorohydrosilanes with diisopropylethylamine. The compound differs from previously reported six-membered silicocyclic ionic compounds. Notably, the chlorine atom in the cation does not form a direct covalent bond with the surrounding atoms. Instead, it forms a hydrogen bond, a feature not observed in the cationic components of other tetradecachlorocyclohexasilane dianion compounds. The structure was confirmed through single-crystal X-ray diffraction, NMR spectroscopy, and elemental analysis. The perchlorinated cyclohexasilane salt was subsequently reduced to cyclohexasilane using metal hydrides, achieving an overall yield of 44.2% across the two-step process. This method offers several advantages, including cost-effectiveness, high yields, simple purification, and mild reaction conditions. The results demonstrate the utility of this approach for synthesizing cyclohexasilane and advancing its applications as feedstocks for silicon deposition in the development of micro- and nano-silicon materials.