Letters in Organic Chemistry - Volume 22, Issue 10, 2025

Carbimazole is a prodrug that inhibits the overproduction of thyroid hormones in the human body. Its active form, methimazole, is produced by biocatalytic transformation in the target organ. This study addresses the chemistry of carbimazole and thiamazole to improve its therapeutic predictability. The study focuses on the optimisation and selection of conditions for the synthesis and hydrolysis of carbimazole, leading to its active derivative. The in vitro study investigated the reaction of thiamazole with iodine ions under programmable process conditions. The results were confirmed using various analytical techniques, including high-performance liquid chromatography (HPLC), liquid chromatography coupled to mass spectrometry (LCMS), infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). As a result, the synthesis of both types of therapeutics was optimised and the model interaction with iodide ions was confirmed based on the derivation of imidazole derivatives.

Leea indica (Burm.f.) Merr. is a Vietnamese traditional medicinal plant used for the treatment of many different diseases. However, there has been no investigation of chemical constituents and biological activities of it. Isolated compounds from L. indica consist of two phenolics, gallic acid (1) and 3,4,3′-tri-O-methylellagic acid (2), two flavonoids, quercitrin (3) and myricitrin (4), three triterpenoids, ursolic acid (5), maslinic acid (6), and hederagenin (7), one alkaloid, tetrandrine (8) and three steroids, β-sitosterol (9), stigmasterol (10), and daucosterol (11). Among them, compounds 2, 6, 7, 8, and 10 were isolated from L. indica for the first time. Moreover, the ethyl acetate extract of leaves (LILE), ethyl acetate extract of stem barks (LISBE), methanol extract of leaves (LILM) from L. indica, and the mixture of β-sitosterol (9) and stigmasterol (10) significantly inhibited nitric oxide (NO) production, with IC50 values of 10.01 ± 0.35, 15.51 ± 0.61, 11.38 ± 1.01, and 59.36±10.23 µg/mL, respectively. The percentage of inhibition of edema reached 26.53% after treatment with daucosterol (11) at a dose of 100 mg/kg b.wt. The LILE was also found to exhibit the greatest cytotoxic effect against all four cell lines tested with IC50 values ranging from 7.22 to 10.65 µg/mL. These results confirmed that the extracts of L. indica leaf and stem bark, as well as compounds 9/10 and 11, exhibit very potential anti-inflammatory and cytotoxic effects.

A new method has been developed for the synthesis of pyrano[3,2-c] and pyrano[2,3-a]carbazole derivatives via a three-component reaction of 4-hydroxycarbazole or 2-hydroxycarbazole, aromatic aldehydes, and arylenaminones. This transformation presumably occurs via Knoevenagel condensation, Michael addition, o-cyclization, elimination, and isomerization sequence of reactions. Noteworthy features of this protocol include easy isolation, good functional group tolerance, and high yields.

This study specifically aimed to identify the presence of non-permitted food colorings in spices and evaluate a novel method for reducing them using silver nanoparticles. Spices, known for their aromatic and pungent qualities, play a crucial role in enhancing the flavor of food and beverages. However, the adulteration of spices presents a serious threat to human health, making it imperative to detect harmful substances. Asparagine-capped silver nanoparticles (Asp-AgNPs) demonstrated remarkable efficacy and could photo-catalytically reduce metanil yellow dye. To assess real-world implications, four samples of turmeric powder were collected from local markets in Agra. The focus was on testing for adulteration with metal yellow, one of the most widely used but prohibited food colorants. The investigation involved carefully observing color changes in the test samples. The results revealed that two out of the four turmeric powder samples contained metanil yellow dye, highlighting a concerning prevalence of adulteration in commonly consumed spices. Asparagine-capped silver nanoparticles (Asp-AgNPs) demonstrated remarkable efficacy, capable of photo-catalytically reducing approximately 95.4% of the adulterant dye within 60 minutes when in contact with the prepared catalyst under optimized conditions. Our findings revealed that the asparagine-capped silver nanoparticles (Asp-AgNPs) performed exceptionally well as catalysts, facilitating a remarkable reduction of metal yellow dye, thus achieving an impressive 95.4% reduction rate. This research suggests that asparagine-capped silver nanoparticles could be significant catalysts for effectively degrading toxic dyes in various applications.

The present article describes a theoretical study of the reaction mechanism involved in the conversion of cholest-4-en-3-one to 5α-cholest-3-eno-[3,4-b] quinoxaline. In this study, the reaction proceeded via condensation, cyclization, and oxidation. The reaction pathway was characterized using Frontier Molecular Orbital analysis and a comparison of relative energies, which were computed using the theoretical approach of Density Functional Theory with the B3LYP/6-31G(d) method. The reaction involved a total of six intermediates and three transition states. The energy barriers of the transition states were also reported. It was determined that, overall, the reaction was an endothermic reaction. The stability of all the structures was confirmed by calculating their respective fundamental frequencies and energy minima. Moreover, these findings have implications for the design of novel steroid derivatives and may aid in the development of synthetic routes for biologically active molecules involving quinoxaline frameworks.

Sheep pox virus (SPPV) presents considerable economic and health challenges, in particular for agricultural areas relying on sheep farming. SPPV encodes for SPPV14, a strong inhibitor of BCL-2-mediated apoptosis, which has sparked interest in identifying and developing multifaceted therapeutics. The SPPV14 protein is currently noticed as a crucial viral aspect that facilitates infection and advances the progression of the disease. Recent studies indicate that flavonoids, which are naturally occurring compounds known for their strong antiviral properties, could offer a promising strategy to inhibit SPPV infection. The current study attempted to explore the inhibitory ability of specific flavonoids on the SPPV14 protein utilizing an in silico molecular docking approach. A selection of ten flavonoids was made for virtual screening and docking studies aimed at the active site of the SPPV14 protein, emphasizing interactions at the Arg84 residue, which is essential for the stability of the viral protein. Using AutoDock Vina, molecular docking simulations were run to assess the binding affinities and possible inhibitory effects of flavonoids. All examined flavonoids exhibited significant binding affinities to SPPV14, with isoxanthohumol showing a remarkable interaction with the Arg84 residue, indicating increased stability in binding and possible inhibitory effects. The chosen flavonoids eliminated the canonical ionic interaction observed in all sheep pox disease SPPV14:BH3 motif complex resulting in apoptosis in SPPV14 docking investigation. These interactions suggest that flavonoids may have the ability to interfere with viral protein function, which may hinder the development of SPPV. In silico analysis suggests that specific flavonoids could act as effective antiviral agents against SPPV, with a particular focus on SPPV14. The findings establish a basis for following in vitro and in vivo investigations with the purpose of confirming the potential of flavonoids as alternative therapeutic agents for the management of sheep pox.

A new series of pyridine-fused pyranoquinoline derivatives have been synthesized via one-pot three-component coupling of hydroxyquinoline, aromatic aldehydes, and 2-aminopropene-1,1,3-tricarbonitrile in the presence of 10 mol% of triethylamine at 80°C in ethanol under reflux conditions. It is an effective synthetic method due to its simple operating procedure, wide range of substrates, column chromatography-free separations, and high product yield.

In this study, we aimed to describe a reconstructed hydrotalcite (Mg-Al LDH) catalyzed synthesis of β-hydroxy ketones from aldol condensation between acetone and aromatic aldehydes under room temperature. The performance of the catalyst, including catalytic activity, reaction selectivity, and reusability, as well as the general applicability of the catalytic method, was thoroughly evaluated. The reconstructed magnesium-aluminum hydrotalcite catalyst described in this study featured easy preparation, low cost, and high safety and efficiency, representing an excellent approach for catalyzing aldol condensation reactions under heterogeneous conditions.

A novel arylalkanone, 1-(2’,6’-dihydroxyphenyl)-4-hydroxy-9-(3”,4”-dihydroxyphenyl)-nonan-1-one (1), along with five known arylalkanones, malbaricone A (2), malbaricone B (3), malbaricone C (4), malbaricone D (5) and 1-(2’, 6’-dihydroxyphenyl) tetradecan-1-one (6), and a dimeric acylphenol, giganteone A (7), which is newly reported for this plant, were isolated and characterized from seed mace of Myristica ceylanica.