Current Organic Chemistry - Volume 29, Issue 2, 2025

A pentacyclic triterpenoid produced from medicinal herbs, fruits, and vegetables, Ursolic acid (UA) has pharmacological activity. This review provides a comprehensive overview of the interactions of UA with molecular targets, its various mechanisms of action, and its clinical implications in cancer therapy. Numerous studies have been conducted on the pharmacological effects of UA, and its biological benefits, such as its anti-inflammatory, antioxidant, and anti-cancer activities, have been demonstrated. The study showed how signaling pathways, such as PI3K/Akt, MAPK, and NF-κB, work together to control cell death, proliferation, and inflammation. UA effectively treats cancer by interacting with molecular targets in cell signaling pathways, making it a potent treatment option. It inhibits tumor cell transformation, limits their reproduction ability, and triggers apoptosis. It also has been found to inhibit various pro-inflammatory transcription factors and cell cycle proteins, such as kinases, cytokines, chemokines, adhesion molecules, and inflammatory enzymes. The targets may aid in UA's chemopreventive and therapeutic benefits by preventing cancer initiation, growth, and metastasis. UA inhibits cancer cell proliferation by arresting and triggering apoptosis through the cell cycle. It is a promising anti-cancer agent with various mechanisms of action. Additionally, it can target multiple signaling pathways and influence the tumor microenvironment, suggesting its potential as a complementary therapy in cancer treatment. Further clinical investigations are needed to entirely understand the therapeutic potential of UA and optimize its application in cancer. This review explores the molecular targets of UA and provides insights into its potential anticancer activities.

Minerals occurring on earth have been used as raw materials by mankind for thousands of years. Currently, more than 6000 mineral species are known, and a few of them are common or abundant. It has long been known that minerals can catalyse chemical processes. The catalytic activity of metallic ore minerals has been investigated primarily in coal liquefaction and prebiotic chemistry and, to a lesser extent, in organic syntheses. This review article discusses organic chemical reactions, in which metallic ore minerals have been used as catalysts.

A practical and novel approach for the regioselective synthesis of 3-arylthioindole derivatives has been accomplished using a combination of indole substrates with p-toluene sulfonyl hydrazide. This methodology employs NIS as the oxidant and PPh3 as the reductant to give the desired 3-arylthioindoles in good to excellent yields. This method offers several advantages, including simplicity, operational ease, and broad substrate scope.

Effective and “green” synthesis of tetraketone derivatives was elaborated. The last compounds developed prominent bactericide activity against both MIC and MBC S. aureus (ATCC-6538P) bacteria. The novelty of this approach is concluded in the application of Al(OH)3 catalyst for the Knoevenagel-Michael cascade reaction of aromatic aldehydes and 1,3-cyclic diketones in water. The process is chemoselective and affords high yield of tetraketones under benign conditions. The catalyst maintained 80% of initial activity within four cycles. The proposed method can be regarded as an alternative to the existing syntheses of biologically active tetraketones that utilize homogeneous and expensive heterogeneous catalysts.

Organocatalysis has been recognized as a part of chemical research for a long time, and it gained significant attention in catalysis in recent decades. Amine catalyst is a substantial type of organocatalysis, and it is successively employed for the activation of carbonyl compounds. This manuscript delves into the exploration of a proline-based organocatalyst for the synthesis of arylidene benzofuranone intermediates, a critical step that facilitates the subsequent construction of aurone-derived azadienes. In this work, we successfully reported the synthesis of arylidene benzofuranone intermediates through Aldol condensation of benzofuranone with different aldehydes enabled by proline-derived organic catalysts. To achieve this strategy, six examples of amine organocatalysts (A1-A6) were evaluated to showcase the optimal catalyst for this transformation. Moreover, the arylidene benzofuranone intermediates were further employed for the synthesis of interesting aurone-derived azadiene substrates through its reaction with TsNH2. Notably, the using of organocatalyst A6 resulted in the delivery of the product with the best yield (94% isolated yield). Under the optimized conditions, different aromatic and heterocyclic containing aldehydes were effectively tolerated to generate the corresponding arylidene benzofuranone intermediates, which further converted to the azadiene products in high to excellent yield. The claimed structures were confirmed by the spectral analysis.

For the first time, a sonochemical method has been developed for the structural rearrangement of [5,6]-open mono- and poly adducts of fullerene C60 containing spirocyclic fragments of camphor analogs into [6,6]-closed isomers. The isomerization reaction occurs with quantitative yield under mild conditions: 1 hour at room temperature. A probable mechanism of sonochemical isomerization has been proposed. Mono- and poly adducts of C60 fullerene containing spirocyclic fragments of camphor analogues were obtained in the reaction of metal complex catalysis by the Pd(acac)2–2PPh3–4Et3Al system with the participation of fullerene and diazo compounds.

Organo-modified carbon nanotubes have recently gained the interest of many research groups. The potential for applying a new generation of organo-modified carbon nanotubes in many technological fields reveals the importance of covalent modifications on nanotubes. In this study, using the microwave synthesis method, multi-walled carbon nanotube (MWCNT) thiophenol derivatives were obtained with a thioesterification reaction. For this purpose, MWCNT-COOH was obtained from MWCNT by oxidation, and MWCNT-COCl was synthesized from MWCNT-COOH. The MWCNT-CO-S-(ortho/meta/para-methyl/methoxy-phenyl) (MA1-MA6) compounds were synthesized through both microwave synthesis methods starting with MWCNT-COCl and Steglich ester reaction of MWCNT-COOH. Products were characterized using Fourier Transform-Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Thermogravimetric Analysis (TGA), and Transmission Electron Spectroscopy (TEM) methods. Furthermore, step numbers, reaction times, and temperatures of obtained molecules, MA1-MA6, were compared. Steglich esterification was found to be the most effective technique for creating these compounds. The photoluminescent characteristics of MWCNT, MWCNT-COOH, and MA1-MA6 compounds were examined. The intensity of the photoluminescence (PL) was found to vary with the location of the functional group. It was detected that the MA2 compound had the highest photoluminescence intensity (6.9x10² a.u.), while the MA1 compound had the second-highest photoluminescence intensity (6.9x10² a.u.). MA1 and MA2 were radiated at low wavelengths of 475-490 nm with high PL values. Possible transitions were n→π* transitions, with high PL values obtained because of the oxygen atom in the methoxy group. It is expected that these materials will find use in imaging devices operating at high temperatures, particularly because structures containing methoxy groups exhibit favourable photoluminescence properties.

The high dipolarophile structure of MWCNT compounds enables them to be used as a reactive 2π member in 1,3-dipolar cycloaddition reactions. N-substituted glycine ester compounds and employed 1,3-dipolar cycloaddition reactions involving azomethine-ylides for the synthesis of multiwalled carbon nanotube compounds that underwent covalent modification. Initially, N-substituted glycine esters (3a) and N-substituted glycine compounds were synthesized. N-substituted glycine (4a) and substituted aromatic aldehyde derivatives were reacted with the dipolarophilic MWCNTs, which have regioselectivity only on (6,6)-bonds, via azomethine ylide intermediates over a 1,3-dipolar cycloaddition reaction to obtain the target pyridine-pyrrole-modified carbon nanotube derivatives (6a-g). The compounds' structural characterizations were achieved using FTIR, Raman, NMR, TEM, UV-VIS, and TGA methods. The dispersibility of the compounds was evaluated in various solvents. The activity of each compound's antimicrobial properties against Escherichia coli was assessed. Based on the obtained results, it was concluded that the compounds, by the method employed, adsorbed Escherichia coli bacteria and decreased the bacterial concentration in their film form. According to the results, the compounds can be used in bacterial adsorption-based purification systems (the eradication of water and environmental pollutants) based on the results obtained.