Search Results (110)

Polymeric materials have become important components in prefilled syringes, drug delivery systems, and advanced medical devices. Background/Objectives: Nitrogen dioxide gas is used for the terminal sterilization of drug delivery systems. For the implementation of sterilization methods, compatibility with materials must be demonstrated such that the materials maintain product requirements and specifications after sterilization and at the time of use (i.e., product shelf life). Methods: Commonly used polymers were selected based on their chemical structures to provide insight into the nature of reactions that occur at the temperature and NO₂ concentration levels used in the sterilization process. After exposure to the NO₂ process, materials were evaluated for chemical, mechanical, and biocompatibility properties. Results: In this paper, we demonstrated the compatibility of polymers comprising carbonyl, unsaturated ester, and ketone groups which have been used in medical devices sterilized with NO₂. No significant chemical or physical changes were observed upon the treatment of Amorphous Polyester, Polysulfone (PSU), Polycarbonate (PC), PolyEtherEtherKetone (PEEK), PolyArylEtherKetone (PAEK), and Polypropylene (PP) with NO₂ at a sterilization temperature of 20 °C. At this relatively low sterilization temperature, the reactions of NO₂ with the polymer do not typically occur because the activation energies of these reactions require much higher temperatures. Conclusions: Not all materials will be compatible with NO₂ sterilization, and even with the established data, many devices will need to have their polymers evaluated for compatibility before moving to NO₂ sterilization. These results will provide guidance to device designers selecting materials for new drug delivery devices and to regulators that review the safety and efficacy of these devices. Full article

Objective: The development of natural and new P-gp modulators to reverse tumor multidrug resistance (MDR). Methods: Test compounds were prepared from the plant Metaplexis japonica, and their ability to reverse P-glycoprotein (P-gp)-mediated MDR was investigated in HepG2/Dox cells. Their effects on P-gp expression and function and their interaction modes with P-gp were also investigated. Results: Natural product 3β,12β,14β, 17β,20(S)-pentahydroxy-5α-pregnan-12β-O-(E)-cinnamate (1) and its new semisynthetic derivative 3β12β,14β,17β,20(S)-pentahydroxy-5α-pregnan-3β-O-nicotinate-12β-O-(E)-cinnamate (1a) were obtained. At non-cytotoxic concentrations of 5 or 10 μM, they significantly reversed the resistance of HepG2/Dox cells to P-gp substrate drugs doxorubicin, paclitaxel, and vinblastine, with reversal folds of 7.1, 118.5, and 198.3 (1), and 18.8, 335.8, and 140.0 (1a), respectively, at 10 μM. Cell apoptosis and expression of caspase 9 were both triggered by the combination of 10 μM of compound 1 or 1a and 500 nM of paclitaxel (p < 0.001). Compound 1 or 1a did not affect P-gp expression, but it did significantly suppress the efflux of Rhodamine 123 out of HepG2/Dox cells (p < 0.001). On the Caco-2 cell monolayer, 1 and 1a were shown to be non-substrates of P-gp, with efflux ratios of 0.83 and 0.89. Molecular docking revealed their strong binding energies (−8.2 and −8.4 kcal/mol) with P-gp, and their direct binding to P-gp was confirmed by their dissociation constants (5.53 µM for 1 and 3.72 µM for 1a), determined using surface plasmon resonance. Conclusions: Compounds 1 and 1a are potential P-gp modulators; they may reverse P-gp-MDR through interacting with P-gp to interfere with substrate binding and transporting, and have the potential to improve the efficacy of paclitaxel or vinblastine drugs for combating P-gp-mediated MDR in tumor cells. Full article

Diaryliodonium salts are an important part of hypervalent iodine chemistry, owing to their highly electrophilic character, non-toxicity, and air and moisture stability, have been identified as an important arylating agent. It has been widely applied in the synthesis of natural products, drugs, and bioactive molecules bearing active α-arylation carbonyl units. Within the domain of α-arylation of carbonyl compounds using diaryliodonium salts, there is a notable absence in the literature of a comprehensive compilation dedicated to exclusive arylation processes involving these compounds. In this review, we focus on the overview of the recent advancements in utilizing diaryliodonium salts for α-arylation reactions, encompassing both racemic and asymmetric approaches to various carbonyl compounds including ketones, esters, enolates, and amides. Furthermore, we discuss the unique advantages and inherent limitations of diaryliodonium salts as arylating agents, as well as the underexplored application potentials that warrant further investigation in this rapidly evolving field. Full article

The efficient synthetic routes and evaluates cytotoxic profiles of denitroaristolochic acids II–V (DAA-II–V) were demonstrated in this study. Based on retrosynthetic analysis, a modular synthetic strategy was developed through Suzuki–Miyaura coupling, Wittig reaction, and bismuth triflate-catalyzed intramolecular Friedel–Crafts cyclization to efficiently construct the phenanthrene core. Process optimization significantly improved yields: aryl bromide intermediate A reached 50.8% yield via bromination refinement, while arylboronic ester intermediate B overcame selectivity limitations. Combining Darzens condensation with Wittig reaction enhanced throughput, achieving 88.4% yield in the key cyclization. Structures were confirmed by NMR and mass spectra. CCK-8 cytotoxicity assays in human renal proximal tubular epithelial cells revealed distinct toxicological profiles: DAA-III and DAA-IV exhibited IC₅₀ values of 371 μM and 515 μM, respectively, significantly higher than the nitro-containing prototype AA-I (270 μM), indicating that the absence of nitro group attenuates but does not eliminate toxicity, potentially via altered metabolic activation. DAA-II and DAA-V showed no detectable cytotoxicity within assay limits, suggesting reduced toxicological impact. Structure–activity analysis exhibited that the nitro group is not essential for cytotoxicity, with methoxy substituents exerting limited influence on potency. This challenges the conventional DNA adduct-dependent toxicity paradigm, implying alternative mechanisms like oxidative stress or mitochondrial dysfunction may mediate damage in denitro derivatives. These systematic findings provide new perspectives for AA analog research and a foundation for the rational use and safety assessment of Aristolochiaceae plants. Full article

Background/Objectives: Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) are highly sensitive clinical imaging modalities, frequently employed in conjunction with magnetic resonance imaging (MRI) or computed tomography (CT) for diagnosing a wide range of disorders. Efficient and robust radiolabeling methods are needed to accommodate the increasing demand for PET and SPECT tracer development. Copper-mediated radiohalogenation (CMRH) reactions enable rapid late-stage preparation of radiolabeled arenes, yet synthetic challenges and radiolabeling precursors’ instability can limit the applications of CMRH approaches. Methods: A series of aryl-boronic acids were converted into their corresponding aryl-boronic acid 1,1,2,2-tetraethylethylene glycol esters [ArB(Epin)s] and aryl-boronic acid 1,1,2,2-tetrapropylethylene glycol esters [ArB(Ppin)s] as stable and versatile precursor building blocks for radiolabeling via CMRH. General protocols for the preparation of ¹⁸F-labeled and ¹²³I-labeled arenes utilizing CMRH of these substrates were developed and applied. The radiochemical conversions (RCC) were determined by radio-(U)HPLC. Results: Both ArB(Epin)s and ArB(Ppin)s-based radiolabeling precursors were prepared in a one-step synthesis with chemical yields of 49–99%. Radiolabeling of the aryl-boronic esters with fluorine-18 or iodine-123 via CMRH furnished the corresponding radiolabeled arenes with RCC of 7–99% and 10–99%, respectively. Notably, a radiohalogenated prosthetic group containing a vinyl sulfone motif was obtained with an activity yield (AY) of 18 ± 3%, and applied towards the preparation of two clinically relevant PET tracers. Conclusions: This approach enables the synthesis of stable radiolabeling precursors and thus provides increased versatility in the application of CMRH, thereby supporting the development of novel PET and SPECT radiotracers. Full article

Matrix metalloproteinase-9 (MMP-9) and lipopolysaccharide (LPS) levels are known to be elevated in obesity and contribute to metabolic dysfunction. 2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), an endogenous ligand of the aryl hydrocarbon receptor (AhR), has been implicated in the regulation of inflammatory responses. This study aimed to determine whether ITE can inhibit LPS-induced MMP-9 expression in monocytic cells and to explore the underlying signaling mechanisms involved. Human monocytic THP-1 cells and primary human monocytes were treated with LPS in the presence or absence of ITE. MMP-9 mRNA and protein levels were assessed using quantitative real-time PCR and ELISA, respectively, while gelatin zymography was employed to evaluate MMP-9 enzymatic activity. Chromatin immunoprecipitation followed by qPCR (ChIP-qPCR) was performed to assess NF-κB and AP-1 binding to the MMP-9 promoter region. Our findings demonstrate that ITE significantly suppresses LPS-induced MMP-9 gene and protein expression. This suppression is associated with a marked reduction in LPS-induced NF-κB and AP-1 transcriptional activity. ChIP-qPCR confirmed that ITE attenuates the recruitment of NF-κB and AP-1 to the MMP-9 promoter, thereby inhibiting its transcription. In summary, ITE downregulates LPS-induced MMP-9 expression by interfering with NF-κB/AP-1 signaling, suggesting a potential anti-inflammatory mechanism that could be relevant in the context of MMP-9-driven inflammatory conditions. Full article

Motivated by the search for novel antimicrobials against opportunistic resistant pathogens and based on the reported antimicrobial activity of phthalimides, two series of phthalimide and N-phthaloylglycine esters were designed to investigate whether the addition of butyl and aryl groups enhances their antimicrobial properties. Thus, in vitro antimicrobial activity, antifungal mechanism of action, effect combined with Chloramphenicol, in silico/vitro toxicity, and a docking molecular were studied. Phthalimide and N-phthaloylglycine aryl esters were obtained in yields of 75–98%. Phthalimide aryl ester 3b (R = Me) showed the best results against Gram-(+) and Gram-(−) bacteria, S. aureus and P. aeruginosa, respectively, and yeast fungi, C. tropicalis and C. albicans, with MIC values equal to 128 µg·mL⁻¹. Regarding the antifungal mechanism of action on C. albicans, the MIC values of compound 3b changed from 128 to 1024 µg·mL⁻¹ in the presence of ergosterol. Furthermore, compound 3b showed synergy with Chloramphenicol against P. aeruginosa, with a FICI value equal to 0.5. Finally, the four most promising compounds had their in silico/vitro toxicity evaluated, which showed moderate toxicity to non-toxicity on Artemia salina larvae. With the exception of Chloramphenicol, all selected compounds, including Fluconazole, are potentially hepatotoxic, but they were predicted not to cause skin sensitization, suggesting a potential application for topical use. Molecular docking revealed that compound 3b exhibits superior binding affinity and stability with the 50S ribosomal subunit (−92.69 kcal·mol⁻¹) compared to Chloramphenicol, and a unique π–sulfur interaction with CYP51, suggesting its potential as a dual-action antibacterial and antifungal candidate against resistant pathogens. Full article

The palladium-catalyzed cross-coupling reaction used for carbon–carbon bond formation is one of the most commonly applied reactions in modern organic synthesis. In this work, a concise strategy was developed for constructing the tetrahydroisoquinoline core, a key structural motif found in many biologically active compounds. This method involves the palladium-catalyzed intramolecular coupling of aryl iodides with ester enolates generated in the presence of K₃PO₄ as a base, resulting in the formation of the tetrahydroisoquinoline ring with an exceptionally high yield of 84%. Full article

Prostate cancer remains a significant global health concern, prompting ongoing exploration of novel therapeutic agents. Licochalcone A, a natural product in the chalcone family isolated from licorice root, is characterized by its enone structure and demonstrates antiproliferative activity in the micromolar range across various cell lines, including prostate cancer. Building on our prior success in enhancing curcumin’s antiproliferative potency by replacing the substituted phenol with a 1-alkyl-1H-imizadol-2-yl moiety, we applied a similar approach to design a new class of licochalcone A-inspired chalcones. The synthesis of these target chalcones involved key [3,3]-sigmatropic rearrangement of aryl prenyl ethers and Claisen–Schmidt condensations, yielding three derivative series. These compounds were evaluated for antiproliferative activity in both androgen receptor (AR)-positive and AR-null prostate cancer cell models using WST-1 cell proliferation assay. Systematic evaluation of licochalcone A across four prostate cancer cell lines indicated a modest advantage over enzalutamide, an FDA-approved AR antagonist, in suppressing 22Rv1 cell proliferation. Interestingly, three ester derivatives by replacing the phenol next to the carbonyl with an alkoxide demonstrated similar antiproliferative potency to licochalcone A in both AR-positive and AR-negative prostate cancer cell lines. This suggests that the phenol moiety on licochalcone A may be a promising site for chemical manipulations to enhance anti-prostate cancer activity. Among the synthesized chalcones, nine derivatives showed improved selectivity for AR-positive LNCaP and 22RV1 cells relative to AR-negative PC-3 and DU145 cells, surpassing licochalcone A in selectivity. Additionally, the antiproliferative potency was highly dependent on the R group attached to the imidazole. Most of the derivatives showed antiproliferative potency against androgen receptor-positive LNCaP and 22Rv1 cells, comparable to that of enzalutamide and licochalcone A. These findings suggest that optimization of licochalcone A-inspired chalcones as potential anti-prostate cancer agents warrants further investigation. Full article

Palladium-catalyzed carbonylation reactions of ortho-phenylene dihalides were studied using aminoethanols as heterobifunctional N,O-nucleophiles. The activity of aryl-iodide and -bromide as well as the chemoselective transformation of amine and hydroxyl functionalities were studied systematically under carbonylation conditions. Aminocarbonylation can be selectively realized under optimized conditions, enabling the formation of amide alcohols, and the challenging alkoxycarbonylation can also be proved feasible, enabling amide-ester production. Intramolecular double carbonylation reaction can be achieved using 1,2-diiodobenzene and amino alcohols featuring secondary amine groups, giving oxazocine derivatives. Useful reaction scope with various amino alcohols was performed with good isolated yields of the targeted compounds. Intramolecular C-O coupling of amide alcohols possessing bromo substituent in adjacent ortho position is also demonstrated as a potential next step in benzoxazepine heterocycle formation. Full article

To predict the behavior of aromatic contaminants (ACs) in complex soil–plant systems, this study developed machine learning (ML) models to estimate the root concentration factor (RCF) of both traditional (e.g., polycyclic aromatic hydrocarbons, polychlorinated biphenyls) and emerging ACs (e.g., phthalate acid esters, aryl organophosphate esters). Four ML algorithms were employed, trained on a unified RCF dataset comprising 878 data points, covering 6 features of soil–plant cultivation systems and 98 molecular descriptors of 55 chemicals, including 29 emerging ACs. The gradient-boosted regression tree (GBRT) model demonstrated strong predictive performance, with a coefficient of determination (R²) of 0.75, a mean absolute error (MAE) of 0.11, and a root mean square error (RMSE) of 0.22, as validated by five-fold cross-validation. Multiple explanatory analyses highlighted the significance of soil organic matter (SOM), plant protein and lipid content, exposure time, and molecular descriptors related to electronegativity distribution pattern (GATS8e) and double-ring structure (fr_bicyclic). An increase in SOM was found to decrease the overall RCF, while other variables showed strong correlations within specific ranges. This GBRT model provides an important tool for assessing the environmental behaviors of ACs in soil–plant systems, thereby supporting further investigations into their ecological and human exposure risks. Full article

Pyrazolo[3,4-b]pyridine scaffolds have been heavily exploited in the development of nitrogen-containing heterocycles with numerous therapeutic applications in the field of medicinal and pharmaceutical chemistry. The present work describes the synthesis of eighteen biaryl pyrazolo[3,4-b]pyridine ester (6a–i) and hydrazide (7a–i) derivatives via the Suzuki cross-coupling reaction. These derivatives were subsequently screened for their therapeutic potential to inhibit the diabetic α-amylase enzyme, which is a key facet of the development of anti-diabetic agents. Initially, the ethyl 4-(4-bromophenyl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-6-carboxylate 4 was synthesized through a modified Doebner method under solvent-free conditions, providing an intermediate for further derivatization with a 60% yield. This intermediate 4 was subjected to Suzuki cross-coupling, reacting with electronically diverse aryl boronic acids to obtain the corresponding pyrazolo[3,4-b]pyridine ester derivatives (6a–i). Following this, the biaryl ester derivatives (6a–i) were converted into hydrazide derivatives (7a–i) through a straightforward reaction with hydrazine monohydrate and were characterized using ¹H-NMR, ¹³C-NMR, and LC-MS spectroscopic techniques. These derivatives were screened for their α-amylase inhibitory chemotherapeutic efficacy, and most of the biaryl ester and hydrazide derivatives demonstrated promising amylase inhibition. In the (6a–i) series, the compounds 6b, 6c, 6h, and 6g exhibited excellent inhibition, with almost similar IC₅₀ values of 5.14, 5.15, 5.56, and 5.20 μM, respectively. Similarly, in the series (7a–i), the derivatives 7a, 7b, 7c, 7d, 7f, 7g, and 7h displayed excellent anti-diabetic activities of 5.21, 5.18, 5.17, 5.12, 5.10, 5.16, and 5.19 μM, respectively. These in vitro results were compared with the reference drug acarbose (IC₅₀ = 200.1 ± 0.15 μM), demonstrating better anti-diabetic inhibitory activity in comparison to the reference drug. The in silico molecular docking study results were consistent with the experimental biological findings, thereby supporting the in vitro pharmaceutical efficacy of the synthesized derivatives. Full article

We report a straightforward and efficient synthesis of 4-methyl-2-oxo-2H-chromen-7-yl benzenesulfonate (3a) and 8-iodo-4-methyl-2-oxo-2H-chromen-7-yl benzenesulfonate (3b) in good yields through an O-sulfonylation reaction of 7-hydroxy-2H-chromen-2-ones 1a and 1b with benzenesulfonyl chloride 2 mediated by triethylamine in dichloromethane at ambient temperature. The aryl sulfonyl esters were characterized using spectroscopic, spectrometric, and thermal analyses. Full article

A common flame-retardant and plasticizer, triphenyl phosphate (TPhP) is an aryl phosphate ester found in many aquatic environments at nM concentrations. Yet, most studies interrogating its toxicity have used µM concentrations. In this study, we used the model organism zebrafish (Danio rerio) to uncover the developmental impact of nM exposures to TPhP at the phenotypic and molecular levels. At concentrations of 1.5–15 nM (0.5 µg/L–5 µg/L), chronically dosed 5dpf larvae were shorter in length and had pericardial edema phenotypes that had been previously reported for exposures in the µM range. Cardiotoxicity was observed but did not present as cardiac looping defects as previously reported for µM concentrations. The RXR pathway does not seem to be involved at nM concentrations, but the tbx5a transcription factor cascade including natriuretic peptides (nppa and nppb) and bone morphogenetic protein 4 (bmp4) were dysregulated and could be contributing to the cardiac phenotypes. We also demonstrate that TPhP is a weak pro-oxidant, as it increases the oxidative stress response within hours of exposure. Overall, our data indicate that TPhP can affect animal development at environmentally relevant concentrations and its mode of action involves multiple pathways. Full article

An efficient palladium-catalyzed carbonylation of aryl fluorosulfates with aryl formates for the facile synthesis of esters was developed. The cross-coupling reactions proceeded effectively in the presence of a palladium catalyst, phosphine ligand, and triethylamine in DMF to produce the corresponding esters in moderate to good yields. Of note, functionalities or substituents, such as nitro, cyano, methoxycarbonyl, trifluoromethyl, methylsulfonyl, trifluoromethoxy, fluoro, chloro, bromo, methyl, methoxy, N,N-dimethyl, and [1,3]dioxolyl, were well-tolerated in the reactions, which could be kept for late-stage modification. The reactions employing readily available and relatively robust aryl fluorosulfates as coupling electrophiles could potentially serve as an attractive alternative to traditional cross-couplings with the use of aryl halides and pseudohalides as substrates. Full article