Letters in Organic Chemistry - Volume 22, Issue 12, 2025

By employing a catalytic proportion of Co-Al2O3-SO3H in a three-component Biginelli-type condensation, combining various aromatic aldehydes, 1,3-cyclohexadione, and urea, practical one-pot synthesis of hexahydroquinazolinone was accomplished. This method yielded hexahydroquinazolinones in good yields, which were further enhanced under reflux conditions. This approach offers several significant advantages, including high efficiency, straightforward reaction conditions, simple workup, reusable catalysts, superior yields, and shorter reaction times. The structure of the produced heterogeneous catalyst Co-Al2O3-SO3H was analyzed using Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM).

The effectiveness of herbal preparations depends on achieving therapeutic plasma concentrations. The in vivo efficacy of phytoconstituents is often hindered by poor lipid solubility, high molecular weight, or degradation in the gastric environment. The liquisolid system is a promising technique for developing herbal pharmaceuticals due to its simple manufacturing process, low production costs, industrial viability, excellent flow and compaction properties, and ability to protect active ingredients from oxidation. The liquisolid technique converts liquid formulations, suspensions, or solutions into dry, free-flowing, and compressible powder blends. This approach enhances drug dissolution rates, maintains the photostability of phytoconstituents, and protects against humidity, thereby extending shelf-life. However, the technique faces challenges, such as carefully selecting excipients and difficulties with high-dose formulations. Overcoming these challenges is crucial to improving the therapeutic efficacy of phytoconstituents in pharmaceutical applications. This review explores the liquisolid technique for phytoconstituent drug delivery by conducting an extensive literature analysis using PubMed, CrossRef, and Google Scholar databases. Advances in excipient selection and formulation strategies can significantly enhance the therapeutic potential of herbal treatments employing liquisolid technology, fostering the development of advanced drug delivery systems in modern pharmaceuticals.

A growing number of applications in the fields of biotechnology, biomedicine, catalysis, and energy storage have resulted from the development of gold nanoparticles (AuNPs), which have garnered considerable attention in recent years due to their unique biochemical, optical, electronic, and catalytic properties. However, the traditional approaches to creating AuNPs, like chemical reduction and physical procedures, frequently call for the use of toxic solvents, dangerous compounds, and large energy inputs, raising questions about environmental sustainability and public health. In recent years, there has been a growing interest in the development of environmentally friendly and sustainable approaches to synthesize AuNPs, often referred to as “green synthesis” or “biogenic synthesis”. Green synthesis of AuNPs involves the use of biocompatible agents, such as plants, microorganisms, and biomolecules, to reduce gold ions and form AuNPs in a single step. Compared to conventional approaches, this strategy has a number of benefits, such as a reduced adverse effect on the environment, cheaper production costs, and better scalability. In this review, we will provide an overview of the current state of green synthesis of AuNPs, highlighting the various biogenic agents and characterization methods that have been employed to date. Furthermore, we shed light on the role of plant-derived biomolecules in the reduction mechanism and stabilization processes. Our review provides researchers with a standard reference for future studies.

The study aims to work on Computational Studies to Optimize Pyrazole Derivatives for Antibacterial Activity. A dataset of 28 Pyrazole derivatives having antibacterial activities was used to generate a pharmacophore hypothesis and a 3D-QSAR model. The established pharmacophore model (DHRRR_1) features three hydrogen bond donors (D), hydrophobic (H), and aromatic ring (R) features, exhibiting favorable parameters (R² = 0.9031; Q² = 0.9004). Hypothesis validation, enrichment analysis, and contour plot analysis were conducted, followed by virtual screening of the ChEMBL database using the optimized pharmacophore model and filtering based on the Lipinski rule of five. Docking was done with PDB ID 3G75 targeting DNA gyrase using Schrodinger software, further Desmond module of Schrodinger 2024-2 was used for MD simulations. The QSAR model was validated along with standard parameters. A library of NCE’s was designed with hypothesis DHRRR_1. Compounds that showed no violations in ADMET studies were further analysed for their interactions in the docking study. Eight compounds have shown zero violations in ADMET and have shown greater binding affinity in comparison to the standard Metronidazole. Further in the MD simulation results, instability of the complex 3G75-Comp D1 was analysed for 100 ns. This study provides a comprehensive approach for identifying novel Pyrazole-based antibacterial agents, highlighting compound D1 as a promising lead. Most promising compound D1 has indicated the role of the Hydroxy group, Pyrazole, and pyrrole ring for good antibacterial activity.

Antioxidants are vital molecules that play a crucial role in maintaining optimal health by neutralizing reactive oxygen species (ROS) and mitigating oxidative stress, which is implicated in various chronic diseases, such as cancer and heart diseases. Apigenin, a naturally occurring flavonoid, has demonstrated significant antioxidant properties through free radical scavenging, metal ion chelation, and modulation of redox signaling pathways. We synthesized a series of novel apigenin derivatives via the Mannich reaction and evaluated their antioxidant activities using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. New derivatives of trihydroxychromen were synthesized and evaluated for their in vitro antioxidant activity. The target compounds were prepared by bonding pharmacophoric moieties possessing antioxidant activity, including amino substituents, via simple and efficient synthetic strategies. Physical and spectral data confirmed the structures of the newly synthesized compounds. The synthesized compounds 4e (IC50 = 0.09 µg/ml), 4i (IC50 = 2.74 µg/ml), and 4j (IC50 = 2.90 µg/ml) showed potential antioxidant activity than gallic acid (IC50 = 4.39 µg/ml) and exhibited moderate to excellent activities, with some derivatives surpassing the standard gallic acid. Molecular docking studies further elucidated the presence of an amino substituent at position 8 in compounds 4i, 4j, and 4e, resulting in good interactions with the receptor molecule's TYR662, ASN710, and GLN553. This study highlights the potential of apigenin derivatives as effective antioxidants with possible therapeutic applications.

The Bacillus cereus group includes eight well-characterized and established species, whose classification and identification have been arduous and intense tasks. The similarity between Bacillus cereus group species and the discovery of new strains have complicated their classification and identification. The chemical profile can be complementary, along with molecular methodologies, to classify Bacillus species. With this issue in mind, we performed a comparative study on natural compounds isolated from Bacillus cereus, Bacillus mycoides, Bacillus thuringiensis, Bacillus weihenstephanensis and Bacillus toyonensis. We isolated compounds from Bacillus cereus, Bacillus mycoides, Bacillus thuringiensis, Bacillus weihenstephanensis and Bacillus toyonensis, elucidating their chemical structure by spectroscopic methods. The data suggests that indolic compounds are isolated from B. thuringiensis, preferentially serving to identify this species. Moreover, macrolactin compounds are extremely specific for B. weihenstephanensis since these compounds are not isolated from any other species. Therefore, the chemical profile of each species can be related to a species of this group, helping to define the type of species. In addition, the data achieved suggest that although genomically B. mycoides and B. weihenstephanensis can be indistinguishable, both species should be treated differently.

This study aimed to carry out highly efficient and simple cross-coupling reactions of arylboronic acid with methyl dithiocarbamates for the synthesis of thioamide derivatives using Ni(acac)2(5 mol%)/TFP(5 mol%) as a catalyst. Under the optimized reaction conditions, the coupling reaction between arylboronic acid with methyl dithiocarbamates was carried out smoothly, and thioamides were obtained with 27-85% isolated yields. Furthermore, dithiocarbamate methyl esters with allyl, cyano, and acid-sensitive ketal functional groups were successfully coupled with phenylboronic acid to produce the desired product, thioamides, with a yield of 27-69%. Aromatic boronic acids with methoxy or formyl groups on the benzene ring were found to be compatible in this reaction system, and the corresponding thioamides were obtained with an isolated yield of 31-43%. A thioamide with 1-(bis(4-fluorophenyl)methyl)piperazine structural units was prepared with a yield of 65%, which has the potential biological activity. However, this reaction system did not achieve satisfactory results for methyl 1H-imidazole-1-carbodithioate. The structures of all the target compounds were confirmed by melting point determination, HMRS, ¹H NMR, and ¹³-CNMR. The broad functional group tolerance and consistent high efficiency at gram-scale synthesis make this protocol a potentially practical approach for producing thioamide derivatives. The method avoids the use of expensive transition metals, such as Pd, Ir, or Rh, and has the advantage of simple operation.