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The bioactive isoflavan glabridin of Glycyrrhiza glabra remains in the limelight because of its widespread pharmacological prospect. Here, a better and eco-friendly synthetic method to (±)-glabridin has been introduced, that relies on a six-step protocol, and that is more overall yielding, less dependent on chromatographic purification, and more operationally simpler than previously described and patented ones. The synthesized (±)-glabridin is very effective antioxidant, showing 87.46% the percentage of inhibition. Antibacterial assay indicates that there is a distinct strain-dependent reaction, with a significant response against Escherichia coli (MIC = 33.8 μM) and moderate efficacy against Staphylococcus aureus (MIC = 125 μM). Cytotoxicity assay and IC50 values show a dose-response profile, (±)-glabridin would not be cytotoxic until 62.5 μM and therefore, these concentrations would be more applicable to mechanistic or efficacy research which would need minimal viability decline and a good safety margin within the assayed concentration range. In addition, molecular docking experiments have been performed against the chosen biological targets, which are in agreement with the experimental findings. On the whole, this study holds a viable and green chemistry principles guided synthesis of (±)-glabridin that indicates how it could be used in multidrug functions and pertains to the future bioorganic and medicinal chemistry research.

Interleukin-4 (IL-4) and its cognate receptor subunit IL-4 receptor alpha (IL-4Rα) constitute a central cytokine-receptor recognition system in type 2 inflammation and represent a challenging therapeutic target at the protein-protein interaction level. The IL-4/IL-4Rα interface is broad, highly polar, and dynamically linked to higher-order receptor assembly, creating substantial barriers to direct small-molecule modulation while also offering a valuable framework for structure-guided ligand design. This review examines the molecular basis of IL-4 signaling with emphasis on receptor recognition, interfacial hotspot residues, heterodimerization with γc or IL-13Rα1, and the structural determinants that govern downstream pathway activation. Clinically validated antibodies targeting IL-4 or IL-4Rα are discussed as important examples of successful interface-directed modulation and as benchmarks for target validation. Particular attention is then given to emerging small-molecule strategies aimed at perturbing IL-4-centered signaling, including direct and indirect modulators, while macrocycles are briefly considered as complementary non-antibody modalities for difficult cytokine-receptor PPI surfaces. By positioning the IL-4/IL-4Rα system as a defined and chemically challenging bioorganic target, this review highlights how biomolecular recognition, interfacial topology, and druggability considerations can inform future efforts to develop next-generation modulators of cytokine-receptor signaling. The article therefore provides a chemistry-oriented perspective on therapeutic intervention at a biologically important immune interface.

Colorectal cancer remains a major global health challenge, highlighting the need for effective and selective anticancer agents. In the present study, a series of pyrazolone-derived sulfonamide analogues (Keum and Giovannucci, 2019a, 2019b; Morgan et al., 2023; Lee et al., 2026; Capuozzo et al., 2025; Li et al., 2024; Xie et al., 2020; Gavrić et al., 2025 (1-8)) was designed, synthesized, and evaluated for anti-colorectal cancer activity. Structural characterization of the synthesized compounds was accomplished using 1H NMR, 13C NMR, and HREI-MS analyses. The cytotoxic potential of the compounds was investigated against HCT-116 and HT-29 colorectal cancer cell lines, while HEK-293 cells were used to assess selectivity toward normal cells. Among the synthesized derivatives, analogue 7 exhibited the strongest antiproliferative activity with IC₅₀ values of 1.80 ± 0.20 μM and 2.00 ± 0.20 μM against HCT-116 and HT-29 cells, respectively, and showed reduced toxicity toward HEK-293 cells (IC₅₀ = 34.60 ± 0.20 μM). The selectivity index of 19.22 and 17.30 was calculated for potent compound 7. Molecular docking studies revealed that compound 7 exhibited the strongest binding affinity toward carbonic anhydrase IX (CA IX), with a docking score of -12.49 kcal/mol, forming favorable interactions within the enzyme active site. Enzyme kinetic analysis and Lineweaver-Burk plots suggested a competitive inhibition mechanism for the lead compound. Additionally, DFT and ADMET investigations confirmed favorable electronic characteristics, molecular stability, drug-likeness, and low predicted toxicity. These findings suggest that pyrazolone-derived sulfonamides represent promising scaffolds for future colorectal cancer drug development.

Pancreatic ductal adenocarcinoma (PDAC) exhibits profound therapy resistance driven by lysosome-dependent nutrient recycling, metabolic adaptation, and stress tolerance. Current lysosome targeting agents such as chloroquine (CQ)/hydroxychloroquine (HCQ) show limited efficacy due to transient activity and dose-limiting-toxicities. To overcome these limitations, we developed lysostilbenes, a new class of hybrid small molecules combining the CQ pharmacophore with lysosome-disrupting stilbene analogs. Stilbene pharmacophore is the core structural component of resveratrol. Among the synthesized hybrids, lysostilbene-4 emerged as the lead candidate, demonstrating ~30-40-fold greater cytotoxicity against PDAC cells than parent compounds, while sparing nonmalignant cells. At nanomolar concentrations, lysostilbene-4 induced rapid, irreversible lysosomal membrane permeabilization (LMP), initiating a lysosome mitochondria apoptotic cascade via CTSB (cathepsin B) release, BID cleavage, BAX activation, and caspase-mediated apoptosis. In parallel, it abrogated lysosomal recovery by significantly reducing repair, lysophagy, autophagosome maturation, and uncoupling TFEB-driven transcriptional programs from effective lysosome biogenesis. Reduced TFEB mRNA expression correlated with poor overall-survival and disease-free-survival across multiple cancer patients, with a particularly strong association in pancreatic cancer patients. Using TFEB+/+ and TFEB-/- knockout pancreatic cancer cells we establish that lysostilbene-4 exerts severe cytotoxicity by inducing persistent lysosomal-damage and disrupting autophagosome-lysosome assembly, with vulnerability further amplified in TFEB-deficient cells. This finding underscores TFEB as a key determinant of lysosomal-resilience and a potential predictive biomarker. Importantly, lysostilbene-4 was well tolerated in preclinical mouse-models at supra-therapeutic doses without systemic-toxicity. These findings position lysostilbene-4 as a first-in-class lysosome-targeting therapeutic that enforces sustained lysosomal collapse while compromising adaptive recovery-mechanisms, providing a mechanistically precise and safe strategy against PDAC.Abbreviations: ALG: autophagy-lysosome genes; AMPK: AMP-activated protein kinase; CASM: conjugation of ATG8s to single membranes; CTSB: cathepsin B; LGALS3: galectin 3; LMP: lysosomal membrane permeabilization; LS: lysostilbene; MTOR: mechanistic target of rapamycin kinase; PDAC: pancreatic ductal adenocarcinoma; TCGA: The Cancer Genome Atlas; TFEB: transcription factor EB; ULK1: unc-51 like autophagy activating kinase 1.

Osteomyelitis, a skeletal infection, is commonly treated with long-term, high-dose antibiotics, carrying the risk of bacterial resistance and treatment failure. There is an urgent clinical need for effective non-antibiotic therapies. Sonodynamic therapy (SDT) activated by ultrasound (US) represents a promising alternative due to its deep tissue penetration and biosafety. Hydroxyapatite (HAP) is a naturally occurring mineral in the human body that exhibits excellent biocompatibility and osteogenic properties. However, the inherently low piezoelectric coefficient of pristine HAP restricts efficacy as a sonodynamic antibacterial agent. In this study, we developed a calcium-deficient HAP (DCP) with enhanced piezoelectric properties through crystal structure modulation via calcium vacancy engineering. This modification optimizes the band structure of DCP, significantly improving its sonodynamic performance under US irradiation. The modified material demonstrates strong bacterial membrane penetration and disruption capabilities, leading to antibacterial outcomes. Additionally, the facilitated electron transfer promotes charge accumulation, which further stimulates osteogenic regeneration and promotes bone formation and mitigates osteolytic damage. In vitro and in vivo results confirm that the DCP-based SDT system not only efficiently eradicates bacteria but also mitigates local inflammation, inhibits osteolytic damage, and supports bone repair. This metal-free, piezoelectric nanoplatform provides a controllable and clinically translatable strategy for treating osteomyelitis without conventional antibiotics.

The title hydrated salt, C16H19FN3O3 +·C2H3O2 -·1.5H2O, crystallizes with two cations, two anions and three water mol-ecules of crystallization in the asymmetric unit. The protonation of the piperazine secondary amine group of norfloxacin occurs via proton transfer from acetic acid. In the extended structure, the components are linked into chains propagating along the a-axis direction through numerous N-H⋯O and O-H⋯O hydrogen bonds. Hirshfeld surface analysis and two-dimensional fingerprint plots confirm the significant contribution of H⋯O inter-actions to the consolidation of the crystal structure.

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RNA viruses, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), flaviviruses, and alphaviruses, represent a major source of emerging human infectious diseases. They pose a persistent threat to public health; however, few therapeutic options are available for severe infections. Through a natural product screening campaign, we identified ansatrienin B as a broad-spectrum inhibitor of multiple RNA viruses, including SARS-CoV-2, flaviviruses (e.g., YFV, WNV, DENV), and alphaviruses (e.g., CHIKV). Time-of-drug-addition assays indicated that ansatrienin B acts at both the early (entry) and intermediate (replication) stages of the viral life cycle. Surface plasmon resonance (SPR) and molecular docking studies validated a direct interaction between ansatrienin B and the RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 and WNV. Combined RNA pull-down and RdRp enzymatic activity assays (in gel, solution, and cellular forms) further demonstrated that ansatrienin B disrupts both the binding of RdRp to viral RNA and its enzymatic activity. In vivo, ansatrienin B showed significant efficacy in mouse models infected with SARS-CoV-2 or WNV infection. To facilitate screening and elucidate the structure-activity relationship (SAR), we generated a focused ansatrienin library via a mutasynthetic approach. Supplementation of four 3,5-AHBA analogs into a ΔmycB1-B4 mutant strain of Streptomyces flaveolus yielded 30 novel ansatrienin derivatives. Evaluation of anti-SARS-CoV-2 activity identified four analogs with enhanced potency, enabling the establishment of a preliminary SAR. Collectively, these findings establish ansatrienin B as a novel inhibitor targeting RdRp and provide a foundation for the development alternative broad-spectrum antiviral agents.

The title compound, bis-(μ-2-carb-oxy-4-nitro-benzoato-κ2 O 1:O 1')bis-[bis-(1,10-phenanthroline-κ2 N,N')cobalt(II)] bis-(2-carb-oxy-4-nitro-benzoate) tetra-hydrate, [Co2(C8H4NO6)2(C12H8N2)4](C8H4NO6)2·4H2O, comprises a centrosymmetric dinuclear cobalt(II) complex dication, two hydrogen 4-nitro-phthalate anions and four water mol-ecules of crystallization. The two CoII atoms are linked by two μ-hydrogen 4-nitro-phthalato ligands, generating a centrosymmetric dinuclear unit. Each cobalt(II) centre adopts a distorted octa-hedral coordination geometry defined by four N atoms from two chelating 1,10-phenanthroline ligands and two O atoms from two symmetry-related bridging hydrogen 4-nitro-phthalate ligands. In the crystal, O-H⋯O and C-H⋯O hydrogen bonds link the ionic components into a three-dimensional supra-molecular framework, which is further reinforced by aromatic π-π stacking inter-actions between neighbouring phenanthroline and hydrogen 4-nitro-phthalate rings, with centroid-to-centroid separations ranging from 3.501 (5) to 3.687 (4) Å. Hirshfeld surface analysis shows that O⋯H/H⋯O contacts make the largest contribution (38.1%) to the crystal packing, confirming the dominant role of hydrogen bonding in consolidating the crystal structure.

Nanoparticles have emerged as a promising strategy in dental implantology to enhance implant integration and therapeutic functionality. Nanostructured surface modifications enable precise control over implant topography and chemistry, leading to increased surface area, improved protein adsorption, and enhanced cellular adhesion, key factors for successful osseointegration. Various nanoparticle systems, including titanium dioxide (TiO₂), hydroxyapatite, and bioactive glass, have been extensively explored for surface modification and functional enhancement of dental implants. In addition to structural benefits, nanoparticles facilitate localized and controlled drug delivery, reducing infection risk, minimizing systemic side effects, and accelerating tissue healing. Despite these advancements, challenges such as long-term stability, biocompatibility, optimization of drug release kinetics, and potential toxicity remain critical barriers to clinical translation. Therefore, further research is required to ensure safe and effective application of nanoparticle-based dental implants in clinical practice.

The therapeutic and biotechnological utility of synthetic oligonucleotides is constrained by the limited chemical diversity of canonical nucleotides and their susceptibility to nuclease degradation. Inspired by the hypermodified genomes of bacteriophages, where 5-glycosylated pyrimidines confer protection against host restriction enzymes, we report the design and synthesis of a scaffold of 5-glycosylated 2'-deoxyuridine triphosphates (dUTPs 1-7) bearing mono- (either neutral or charged moieties) and oligosaccharides affixed to position 5 of the nucleobase. The resulting glyco-modified nucleotides were well incorporated into DNA by different template-dependent polymerases, but much less by template-independent polymerases. While the presence of charged residues did not affect incorporation efficiency, glycan side-chain extension considerably reduced the incorporation yield of the glycosylated nucleotides. On the other hand, the saccharide appendages did not affect the serum stability of the 71-mer sequences containing the glyco-modified dUTPs and were only slightly destabilizing duplex DNA. Interestingly, the presence of short oligosaccharides highly increased the oligonucleotide stability against the BfaI endonuclease. These findings show that 5-glycosylation with short oligosaccharides could be a strategy to expand the chemical arsenal on nucleobases of DNA, offering a robust strategy for developing next-generation glyco-aptamers with enhanced endonuclease stability and novel saccharide-mediated recognition capabilities.

Specialized metabolites are often distributed sporadically across distantly related plant lineages, a pattern commonly attributed to convergent evolution, although the genomic processes enabling such innovation remain poorly understood. Here, we demonstrate that parasitic dodders (Cuscuta spp.) accumulate the lignan sesamin, a compound previously considered characteristic of sesame (Sesamum indicum) and related Lamiales species. We identified Cuscuta homologs of S. indicum CYP81Q1, which encodes piperitol/sesamin synthase (PSS), and demonstrated that these proteins retain catalytic PSS activity in vitro. Phylogenetic analyses indicate that CYP81Q was horizontally transferred from a Lamiales host to an ancestral Cuscuta lineage. Parasitism by C. campestris induces host CYP81Q expression and enhances interspecific transfer of genetic material across the haustorial interface, providing a mechanistic basis for horizontal gene transfer (HGT). Notably, comparative genomic analyses reveal that following horizontal acquisition, the transferred gene underwent extensive structural remodeling, characterized by sequential intron gains, while its enzymatic function was preserved. Many of the newly acquired introns exhibit hallmarks of insertion and excision of transposable elements, suggesting that mobile genetic elements contributed to post-transfer gene restructuring. The intron-rich architecture of Cuscuta CYP81Q was stably maintained throughout species diversification. Together, these findings suggest that parasitism-mediated HGT can be followed by intronization and transposon colonization, resulting in the generation of structurally complex yet functional genes. This process represents an underappreciated mechanism through which parasitic plants remodel horizontally acquired genes to facilitate metabolic innovation.

The microbial production of pantothenic acid (d-PA) is critically limited by feedback inhibition and low activity of the key enzyme ketopantoate hydroxymethyltransferase (KPHMT). To overcome this, rational enzyme mining based on computational prediction was established. Following sequence conservation analysis, molecular dynamics simulations, and binding free energy (ΔG) calculations, five representative native KPHMT enzymes were selected for experimental validation: EcKPHMT from Escherichia coli, CgKPHMT from Corynebacterium glutamicum, MpKPHMT from Mangrovibacter plantisponsor, EpKPHMT from Enterovibrio pacificus, and BsKPHMT from Bacillus subtilis. EpKPHMT and BsKPHMT exhibited 4.25- and 4.60-fold times that of EcKPHMT, respectively, with relieved pantoate feedback inhibition (IC50: 14.07 and 19.86 mM vs. 1.08 mM) and virtually no inhibition by d-PA. The strain expressing BsKPHMT enhanced d-PA and pantoate titers by 74.30% (3.12 g/L) and 140.0% (0.84 g/L) in shake flasks, and further increased d-PA production by 55.4% in a 5 L bioreactor, over the control. This work established a predictive framework for mining superior enzymes based on in silico prediction, offering a valuable strategy for metabolic engineering of high-value chemicals.IMPORTANCEThe industrial-scale biosynthesis of pantothenic acid (d-PA) is often bottlenecked by the strict feedback inhibition of its key biosynthetic enzyme, ketopantoate hydroxymethyltransferase (KPHMT). This study describes a computational strategy for the mining and selection of naturally occurring KPHMTs with reduced feedback inhibition, providing superior genetic parts for metabolic applications. This approach provides a novel and rational framework for mining allostery-free enzymes, successfully delivering two highly efficient biocatalysts, BsKPHMT and EpKPHMT. These biocatalysts exhibit immediate potential for industrial applications, offering a direct solution to enhance the production of both pantoate and d-PA. Collectively, the integrated methodology demonstrates effective translation from fundamental discovery to practical application, presenting a generalizable model for overcoming similar metabolic bottlenecks.

A mild, visible-light-driven protocol has been developed for the regioselective ortho-C(sp2)-H mono-halogenation (Cl, Br, and I) of 3-aryl-2H-benzo[b][1,4]oxazin-2-ones via a synergistic metallaphotoredox strategy. The transformation employs Pd(OAc)2 (20 mol %) in combination with the organic photocatalyst eosin Y (WS, 10 mol %) under irradiation with a 24 W blue LED, using bench-stable N-halo-5,5-dimethylhydantoins (DCDMH, DBDMH, and DIDMH) as sustainable halogen sources. Conducted in 1,2-dichloroethane (DCE) with p-toluenesulfonic acid (1.0 equiv.) as an essential additive, the reaction proceeds under oxidant-free and thermally mild conditions to afford ortho-halogenated products in high isolated yields (75%-97%) with excellent regioselectivity. A broad range of substituents on the 3-aryl ring, including electron-donating, electron-withdrawing, and extended aromatic groups, are well tolerated. Mechanistic investigations-including radical trapping experiments (TEMPO, BHT), light on/off studies, and control reactions-support a cooperative pathway involving Pd(II)-directed C─H activation and photoredox-mediated generation of halogen radicals, followed by radical capture and reductive elimination from high-valent palladium intermediates. This operationally simple dual catalytic approach provides an efficient platform for late-stage diversification of pharmaceutically relevant 2H-benzo[b][1,4]oxazin-2-one scaffolds and advances sustainable strategies in photocatalytic C─H halogenation.

Zebrafish (Danio rerio) is a powerful vertebrate model organism with strong genetic and physiological similarity to humans, yet its use in large-scale transcriptomic research remains constrained by incomplete gene annotations, inefficient ribodepletion methods, and limited transcript-level resolution. To tackle these challenges, we applied CapTrap-seq, a platform-agnostic long-read RNA sequencing approach combining cap-trapping with oligo(dT) priming to selectively capture 5'-capped, full-length transcripts, to zebrafish developmental stages and adult tissues. We further introduce a size-selection step that substantially improves recovery of longer RNA molecules without compromising quantitative accuracy. Benchmarking against the template-switching oligo (TSO) approach demonstrated that CapTrap-seq enables accurate and reproducible transcript reconstruction in a non-mammalian system without requiring external ribodepletion or validation resources. Comparative analysis across multiple long-read catalogues showed that CapTrap-seq detected the largest number of biologically and clinically relevant genes, including oxidative phosphorylation, cardiac, and Online Mendelian Inheritance in Man (OMIM) disease genes, while revealing extensive isoform diversity absent from current annotations. Analysis of the carmn and dancr lncRNA loci further demonstrated the ability to resolve complex splicing landscapes, uncovering novel full-length isoforms with distinct domain architectures not represented in existing zebrafish reference annotations. CapTrap-seq thus emerges as a robust, genome-agnostic framework for high-quality transcriptome characterisation in zebrafish and other under-annotated species, with broad implications for functional genomics and translational research.

Dittrichia viscosa (L.) is widely recognized in alternative medicine in the Mediterranean area for its therapeutic purposes. This study evaluates the acute and subacute toxicity of polar and non-polar extracts of D. viscosa when administered orally or applied topically. Toxicity tests were conducted at a dose of 2000 mg/kg on Wistar rats over 14 days for acute toxicity and 28 days for subacute toxicity. Parameters assessed included body weight, behavioral observations, hematological analysis, serum biochemistry, and histopathological examinations. No significant toxic effects were observed after a single administration of 2000 mg/kg of D. viscosa extracts. Furthermore, during the 28-day sub-acute toxicity study, daily doses of 2000 mg/kg were well-tolerated without inducing mortality, clinical signs of toxicity, or significant changes in behavior, body weight, or physiological status in either male or female rats. Hematological parameters remained stable, and there were no disruptions in liver function enzymes, glucose, or creatinine levels, confirming normal hepatic and renal function. These findings suggest that D. viscosa extracts are non-toxic and safe for oral and dermal use.

RNA modifications constitute a dynamic layer of gene regulation during development. Among them, noncanonical caps, N6-methyladenosine (m6A), and pseudouridine (Ψ) represent three major classes of chemical marks. Noncanonical caps diversify the 5' end of RNA, whereas m6A and Ψ act as internal modifications that modulate RNA structure and RNA-protein interactions. Through these molecular effects, noncanonical caps, m6A, and Ψ influence RNA processing, localization, and function, thereby governing RNA fate in response to developmental and environmental cues. Advances in detection, quantification, and transcriptome-wide profiling have greatly expanded our understanding of these modifications, while revealing important technical challenges. In this review, we discuss how these three major RNA modifications regulate developmental programs in plants and animals, with emphasis on their molecular mechanisms and biological functions. We further highlight their potential relevance for therapeutic strategies in human diseases and agricultural approaches for crop improvement under climate change.

Anaplastic thyroid carcinoma (ATC) exhibits extreme malignancy with a median survival of less than 6 months. Traditional therapeutic approaches yield limited efficacy, necessitating the urgent identification of novel treatment strategies. The tumor hypoxic microenvironment serves as a key driver of ATC progression and drug resistance, in which the transcription factor hypoxia-inducible factor 1α (HIF-1α) orchestrates key processes in regulating tumor metabolism, immune evasion, and resistance to cell death. Ferroptosis is a novel iron-dependent form of programmed death, defined by excessive peroxidation of polyunsaturated fatty acid phospholipids (PUFA-PL) within cellular membranes. In this study, cellular and xenograft models were employed to demonstrate that hypoxia confers ferroptosis resistance to ATC cells. Lipid metabolomics analysis revealed HIF-1α regulates lipid metabolism, and acyl-CoA synthase 4 (ACSL4) was identified as key lipid metabolism-related candidate. Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays were used to assess the binding of HIF-1α to the hypoxia-response element (HRE) within the ACSL4 promoter region. Flow cytometric analysis was performed to investigate how HIF-1α inhibition augments the antitumor immunogenicity of PD-1 blockade, as evidenced by enhanced intratumoral CD8+ T-cell infiltration and cytokine secretion. This study identifies a key mechanism by which HIF-1α provides ferroptosis resistance in ATC under the intrinsically hypoxic tumor microenvironment. HIF-1α directly binds the HRE within the ACSL4 promoter, transcriptionally repressing ACSL4 and consequently curtailing PUFA-PL biosynthesis, thereby conferring ferroptosis resistance on ATC cells. In addition, combined treatment with HIF-1α inhibitor and PD-1 blockade effectively suppresses tumor progression and enhances intratumoral CD8+ T-cell infiltration. This study elucidates the molecular mechanism by which HIF-1α mediates anti-ferroptosis in ATC through regulating lipid metabolism and proposes a promising therapeutic strategy in which HIF-1α inhibition acts synergistically with PD-1 blockade for the treatment of ATC.

There exist two pathways in the cleavage of ester bonds, R-(O═)C-O-C-R', which are central to polyester recycling and organic synthesis. Traditional views emphasize electronic effects, where the more positively charged carbon is considered the preferred site for nucleophilic attack, resulting in the breaking of Cacyl-O bond. However, halide based ionic liquids were found to selectively cleave the Calkoxy-O bond of polyesters, a finding that cannot be rationalized by charge considerations alone. In this work, we propose that it is the presence of clusters in solutions that leverages the accessibility of reactants and thus determines the reaction pathways. The idea has been demonstrated in the study of a model binary system of methyl benzoate (MB) and 1-butyl-3-methylimidazolium bromide ([BMIm]Br) using excess infrared spectroscopy, molecular dynamics simulations, and density functional theory calculations. Excess infrared spectroscopy reveals seven distinct aggregate species in solution, including ionic liquid-ester clusters and MB self-aggregates, providing direct experimental evidence that the solution is microheterogeneous and that cluster formation dictates the local reaction environment. In the catalytically relevant cluster, [BMIm]Br(MB)3, DFT optimized geometries show that the Br-···Calkoxy distance (3.56 Å) is significantly shorter than the Br-···Cacyl distance (5.53 Å). Molecular dynamics simulations confirm the preferential solvation of Calkoxy around Br-. A potential energy surface scan with respect to the Br-···C distance identifies a critical distance of approximately 3.5 Å where the alkoxy C-O bond begins to deviate from equilibrium, marking the incipient stage of partial bonding. At 2.34 Å, the Calkoxy-O bond undergoes abrupt elongation, corresponding to an energy maximum, showing a pattern of the transition state in classic SN2 reactions. These findings establish the proximity effect, through cluster mediated spatial preorganization, as the governing principle of C-O bond cleavage selectivity in ionic liquid-ester systems.