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A new and facile route for the one-pot synthesis of 3,12-dicyano-3,6,9,12-tetraazadispiro[5.2.59.26 ]hexadecane-6,9-diium dibromide as a dispirotripiperazine source was introduced by the simple reaction of 1,4-diazabicyclo[2.2.2]octane (DABCO) with cyanogen bromide (BrCN) under mild condition at room temperature. The hydrolysis of dicyanamide moieties in the prepared dispiro compound gave 3,12-diaza-6,9-diazoniadispiro[5.2.5.2]hexadecane dibromide with the dispirotripiperazine (6-6-6) core. The molecular structure of the new compound was characterized by FT-IR,1 H,13 C, HSQC NMR spectroscopy, mass and CHN analysis, and X-ray crystallography technique. [ABSTRACT FROM AUTHOR]

Herein, we describe the first consistent regiospecific reaction of isothiocyanates with a variety of substituted N-arylcyanothioformamides in a 1:1 molar ratio to generate a series of imidazolidineiminodithiones decorated with a multitude of functional groups on both aromatic rings. The reaction is carried out at room temperature using a 20 mol% catalytic amount of triethylamine with DMF as the solvent to selectively form the mentioned products with exclusive regioselectivity. The methodology features wide substrate scope, no requirement for chromatography, and good to high reaction yields. The products were isolated by simple ether/brine extraction and the structures were verified by multinuclear NMR spectroscopy and high accuracy mass measurements. The first conclusive molecular structure elucidation of the observed regioisomer was established by single-crystal X-ray diffraction analysis. Likewise, the tautomer of the N-arylcyanothioformamide reactant was proven by X-ray diffraction analysis. Density functional theory computations at the B3LYP-D4/def2-TZVP level in implicit DMF solvent were conducted to support the noted regiochemical outcome and proposed mechanism. [ABSTRACT FROM AUTHOR]

Pure shift NMR spectroscopy enables the robust probing on molecular structure and dynamics, benefiting from great resolution enhancements. Despite extensive application landscapes in various branches of chemistry, the long experimental times induced by the additional time dimension generally hinder its further developments and practical deployments, especially for multi‐dimensional pure shift NMR. Herein, this study proposes and implements the fast, reliable, and robust reconstruction for accelerated pure shift NMR spectroscopy with lightweight attention‐assisted deep neural network. This deep learning protocol allows one to regain high‐resolution signals and suppress undersampling artifacts, as well as furnish high‐fidelity signal intensities along with the accelerated pure shift acquisition, benefitting from the introduction of the attention mechanism to highlight the spectral feature and information of interest. Extensive results of simulated and experimental NMR data demonstrate that this attention‐assisted deep learning protocol enables the effective recovery of weak signals that are almost drown in the serious undersampling artifacts, and the distinction and recognition of close chemical shifts even though using merely 5.4% data, highlighting its huge potentials on fast pure shift NMR spectroscopy. As a result, this study affords a promising paradigm for the AI‐assisted NMR protocols toward broader applications in chemistry, biology, materials, and life sciences, and among others. [ABSTRACT FROM AUTHOR]

Sesquiterpene lactones (SL) represent a class of secondary metabolites found in the Asteraceae family, notable for their unique structures. The SL α‐santonin (1) and its derivatives are worthy of mention due to their diverse biological properties. Additionally, 4H‐chromenes and 4H‐chromones are appealing frameworks holding the capability to be used as structural motifs for new drugs. Furthermore, unambiguous structural elucidation is crucial for developing novel compounds for diverse applications. In this context, it is common to find in the literature molecules erroneously assigned. Therefore, the use of quantum mechanical calculations to simulate NMR chemical shifts has emerged as a valuable strategy. In this work, we conceived the synthesis of two halogenated 4H‐chromenediones derived from photosantonic acid (2), a photoproduct arising from irradiation of α‐santonin (1) in the ultraviolet region. The structure of the chlorinated and brominated products was determined by NMR analysis, with the aid of quantum mechanical calculations at the B3LYP/6‐311 + G(2d,p)//M062x/6‐31 + G(d,p) level of theory. All analyses were in agreement and led to the assignment of the brominated 4H‐chromene‐2,7‐dione as (3S,3aS,5aR,9bS)‐5a‐(2‐bromopropan‐2‐yl)‐3‐methyl‐3,3a,5,5a,8,9b‐hexahydro‐4H‐furo[2,3‐f]chromene‐2,7‐dione (11b) and of the chlorinated 4H‐chromene‐2,7‐dione as (3S,3aS,5aR,9bS)‐5a‐(2‐chloropropan‐2‐yl)‐3‐methyl‐3,3a,5,5a,8,9b‐hexahydro‐4H‐furo[2,3‐f]chromene‐2,7‐dione (12b). The diastereoselectivities of the reactions were explained based on products and intermediates formation energy calculated using B3LYP/6‐31 + G(d,p) as the level of theory. Structures 11b and 12b were identified as the thermodynamic and kinetic products of the reaction among all candidates. Consequently, the strategy utilized in this study is robust and successfully illustrates the use of quantum mechanical calculations in the structural elucidation of new compounds with potential applications as novel drugs or products. [ABSTRACT FROM AUTHOR]

Purpose: The traditional Chinese herbal medicine Suaeda salsa (L.) Pall (S. salsa) with a digesting food effect was taken as the research object, and its chemical composition and action mechanism were explored. Methods: The chemical constituents of S. salsa were isolated and purified by column chromatography, and their structures were characterized by nuclear magnetic resonance. The food accumulation model in mice was established, and the changes of the aqueous extract of S. salsa in gastric emptying and intestinal propulsion rate, colonic tissue lesions, serum brain-gut peptide hormone, colonic tissue protein expression, and gut microbiota structure were compared. Results: Ten compounds were isolated from S. salsa named as naringenin (1), hesperetin (2), baicalein (3), luteolin (4), isorhamnetin (5), taxifolin (6), isorhamnetin-3-O-β-d-glucoside (7), luteolin-3′-d-glucuronide (8), luteolin-7-O-β-d-glucuronide (9), and quercetin-3-O-β-d-glucuronide (10), respectively. The aqueous extract of S. salsa can improve the pathological changes of the mice colon and intestinal peristalsis by increasing the rate of gastric emptying and intestinal propulsion. By adjusting the levels of 5-HT, CCK, NT, SS, VIP, GT-17, CHE, MTL, and ghrelin, it can upregulate the levels of c-kit, SCF, and GHRL protein, and restore the imbalanced structure of gut microbiota, further achieve the purpose of treating the syndrome of indigestion. The effect is better with the increase of dose. Conclusion: S. salsa has a certain therapeutic effect on mice with the syndrome of indigestion. From the perspective of "brain-gut-gut microbiota", the mechanism of digestion and accumulation of S. salsa was discussed for the first time, which provided an experimental basis for further exploring the material basis of S. salsa. [ABSTRACT FROM AUTHOR]

The synthesis of the phosphorus‐capped heptaphenylsilsesquioxane T7Ph7P is reported. We show that, unlike previous examples, it readily forms Lewis acid‐base adducts with boranes of different steric demand and the FeCO4 fragment. All complexes were characterized by multinuclear NMR and IR spectroscopy in solution and the solid state. The molecular structures of the adducts with BPh3 and B(C6F5)3 were determined from XRD suitable single crystals. The relative conformation of the Ph and C6F5 rings in T7Ph7P−B(C6F5)3 suggests favorable π‐interactions, stabilizing the adducts to such a degree that attempts to activate H2 or CO2 were unsuccessful. [ABSTRACT FROM AUTHOR]

Four new tirucallane-type triterpenoids, polystanins H–K (1–4), were obtained from the stems and leaves of Aphanamixis polystachya. Their structures were elucidated by analysis of the spectroscopic data and comparison with literature data. Compounds 1 and 2 showed week inhibitory effects against NO production in LPS-stimulated RAW264.7 cells. All the isolates were investigated for their antifungal activities against drug-resistant Candida albicans. [ABSTRACT FROM AUTHOR]

Nine jatrophane diterpenoids were isolated from the whole plant Euphorbia helioscopia, including two new ones, helioscopnins A (1) and B (2). Comprehensive spectroscopic data analysis and ECD calculations elucidated their structures, including absolute configurations. All compounds were evaluated for bioactivity towards autophagic flux by flow cytometry using HM mCherry-GFP-LC3 cells. Compounds 1, 3, 4, 5, 8, and 9 significantly increased autophagic flux. [ABSTRACT FROM AUTHOR]

Two new triterpene fatty acid esters, 3β-palmityloxy-12,27-cyclofriedoolean-14-en-11α-ol (1) and 3β-palmityloxy-19α-hydroxyursane (2), together with 3β-hydroxy-11-oxo-olean-12-enyl palmitate (3) were isolated from the potent anti-inflammatory active fraction of the petroleum ether-soluble part of Cirsium setosum ethanol extract. Compound 1 was found to be a rare 12,27-cyclopropane triterpenoid. Their structures were determined through spectral data analysis combined with literature reports. Furthermore, in vitro experiment, compounds 1-3 exhibited significant inhibitory effects on nitric oxide production in lipopolysaccharide-activated mouse RAW264.7 macrophages. [ABSTRACT FROM AUTHOR]

A new 14-membered resorcylic acid lactone (RAL14), chaetolactone A (1), along with three known ones (2−4), was obtained from the fermentation of the soil-derived fungus Chaetosphaeronema sp. SSJZ001. Their structures were established based on extensive spectroscopic data analyses (UV, IR, HRESIMS, 1D, and 2D NMR),13C NMR chemical shifts calculations coupled with the DP4+ probability method, theoretical calculations of ECD spectra, as well as X-ray diffraction analysis. All compounds were evaluated for their cytotoxic effects against A549, HO-8910, and MCF-7 cell lines. [ABSTRACT FROM AUTHOR]

Many 1,2,4-triazole derivatives have high biological activity. They are of interest for scientific and practical human activity as potential drugs and pesticides. In this work, we report a synthesis of a series of new 3-amino-1,2,4-triazole derivatives containing an alkylamide moiety. It was found that the amidoalkylation of 3-amino-1,2,4-triazole N-(1,2,2,2-tetrachloroethyl)carboxamides in the presence of triethylamine occurred selectively at the endocyclic nitrogen atom N-1 with the formation of the corresponding N-(1-(5-amino-1H-1,2,4-triazol-1-yl)-2,2,2-trichloroethyl)carboxamides. The reaction products were isolated in 79–85% yields and characterized by 1H NMR and 13C NMR spectroscopy. To unambiguously establish the structure of the obtained compounds, we carried out X-ray diffraction analysis for N-(1-(5-amino-1H-1,2,4-triazol-1-yl)-2,2,2-trichloroethyl)-3-methylbutanamide. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis and structural characterization of new compounds that integrate thiazolidine-2,4-dione, acridine moiety, and an acetamide linker, aiming to leverage the synergistic effects of these pharmacophores for enhanced therapeutic potential. The newly designed molecules were efficiently synthesized through a multi-step process and subsequently transformed into their hydrochloride salts. Comprehensive spectroscopic techniques, including nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), infrared (IR) spectroscopy, and elemental analysis, were employed to determine the molecular structures of the synthesized compounds. Biological evaluations were conducted to assess the therapeutic potential of the new compounds. The influence of these derivatives on the metabolic activity of various cancer cell lines was assessed, with IC50 values determined via MTT assays. An in-depth analysis of the structure–activity relationship (SAR) revealed intriguing insights into their cytotoxic profiles. Compounds with electron-withdrawing groups generally exhibited lower IC50 values, indicating higher potency. The presence of the methoxy group at the linking phenyl ring modulated both the potency and selectivity of the compounds. The variation in the acridine core at the nitrogen atom of the thiazolidine-2,4-dione core significantly affects the activity against cancer cell lines, with the acridin-9-yl substituent enhancing the compounds' antiproliferative activity. Furthermore, compounds in their hydrochloride salt forms demonstrated better activity against cancer cell lines compared to their free base forms. Compounds 12c·2HCl (IC50 = 5.4 ± 2.4 μM), 13d (IC50 = 4.9 ± 2.9 μM), and 12f·2HCl (IC50 = 4.98 ± 2.9 μM) demonstrated excellent activity against the HCT116 cancer cell line, and compound 7d·2HCl (IC50 = 4.55 ± 0.35 μM) demonstrated excellent activity against the HeLa cancer cell line. Notably, only a few tested compounds, including 7e·2HCl (IC50 = 11.00 ± 2.2 μM), 7f (IC50 = 11.54 ± 2.06 μM), and 7f·2HCl (IC50 = 9.82 ± 1.92 μM), showed activity against pancreatic PATU cells. This type of cancer has a very high mortality due to asymptomatic early stages, the occurrence of metastases, and frequent resistance to chemotherapy. Four derivatives, namely, 7e·2HCl, 12d·2HCl, 13c·HCl, and 13d, were tested for their interaction properties with BSA using fluorescence spectroscopic studies. The values for the quenching constant (Ksv) ranged from 9.59 × 104 to 10.74 × 104 M−1, indicating a good affinity to the BSA protein. [ABSTRACT FROM AUTHOR]

We report the stepwise synthesis of a novel series of heterometallic gold(I)/palladium(II) complexes supported by heteroditopic imidazol‐2‐ylidene/triazol‐5‐ylidene ligands. All new compounds were characterized by means of 1H and 13C NMR spectroscopy, melting points, and elemental analyses. The versatility of the ligand platforms, additionally allows for the preparation of cationic chelate biscarbenic palladium(II) complexes through full deprotonation of the mixed azolium precursors. Characterization studies were completed by the determination of the molecular structures of some synthetic intermediates. The new biscarbenic palladium(II) complexes were tested as catalysts in the cross‐coupling of boronic acid to a variety of chloroarenes and the hydrosilylation of terminal alkynes. Both catalytic processes provide good to excellent yields under low catalyst loadings. [ABSTRACT FROM AUTHOR]

Humins, (side-)products of the acid-catalysed dehydration of carbohydrates, will be produced in substantial quantities with the development of industrial biorefining processes. Most structural knowledge about such humins is based on synthetic model humins prepared at lab-scale from typical carbohydrate(-derived) compounds. Here, we report the first extensive characterisation study of an industrial humin. The soluble humin was generated from pilot plant-scale methanolic cyclodehydration of D-fructose to 5-methoxymethyl-2-furfural (MMF), as part of the Avantium YXY® process to produce FDCA. Purification of the industrial humin followed by fractionation allowed isolation of a water-insoluble, high molecular weight fraction (WIPIH) and a water-soluble, low-to-middle molecular weight soluble fraction (WES). Characterisation by elemental analysis, thermogravimetry, IR and NMR spectroscopy and size exclusion chromatography provided a detailed picture of the humin structure in both fractions. Aided by a comprehensive NMR spectral library of furanic model compounds, we identified the main furanic building blocks and inter-unit linkages and propose a structure for this industrial humin sample. The WIPIH and WES fractions were found to be composed of furanic rings interconnected by short aliphatic chains containing a wide range of functionalities including alcohols, ethers, carboxylic acids, esters, aldehydes and ketones. The low level of crosslinking and high functional group content of the industrial humin differ from the more extensively studied, (highly over-)condensed synthetic model humins, towards which they can be considered intermediates. The structural and compositional insights into the nature of an actual industrial humin open up a broad spectrum of valorisation opportunities. [ABSTRACT FROM AUTHOR]

The reactions of triammino(tricarbonyl)chromium (I) with 1,3-benzodioxane (L1), 2-methyl-1,3-benzodioxane (L2), and 2-phenyl-1,3-benzodioxane (L3) afford new complexes: (η6-C8H8O2)Cr(CO)3 (II), exo- and endo-[2-Me-(η6-C8H7O2)]Cr(CO)3 (III, IV), exo- and endo-[2-Ph-(η6-C8H7O2)]Cr(CO)3 (V, VI), [2-(η6-Ph)-C8H7O2]Cr(CO)3 (VII), and endo-[2-(η6-Ph)]Cr(CO)3-[η6-C8H7O2]Cr(CO)3 (VIII). The structures, compositions, and purity of the synthesized products are proved by UV, IR, and 1H NMR spectroscopy, HPLC, and mass spectrometry. The molecular structures of complexes IV–VI are determined by XRD (CIF files CCDC nos. 2263301 (IV), 2295552 (V), and 2237106 (VI)). A possibility of coordination of the tricarbonylchromium group at different sides of the phenylene ring of ligands L2 and L3 and on the phenyl substituent of ligand L3 is shown. [ABSTRACT FROM AUTHOR]

The reaction of Ru3(CO)10(µ-Ph2AsCH2AsPh2) and arsine ligand (AsPh3) afforded a new triruthenium cluster derivative, Ru3(CO)9(µ-Ph2AsCH2AsPh2)(AsPh3) (1). 1 was synthesised and characterised by elemental analysis, Fourier transform infrared, 1H nuclear magnetic resonance (NMR) and 13C{1H} NMR spectroscopy. The molecular structure of 1 was confirmed by single crystal X-ray diffraction (SXRD) analysis. The compound features a bidentate ligand of Ph2AsCH2AsPh2 and a monodentate ligand of AsPh3 that occupy the equatorial positions at Ru atoms. The thermal decomposition of 1 investigated by the thermogravimetric-differential thermogravimetric (TG-DTG) technique involves three stages, with the final product being Ru atoms with a residual rate of 18.60% (calcd: 18.41%). Density functional theory (DFT) calculations were performed using the B3LYP hybrid exchange–correlation functional method, and the LanL2DZ pseudopotential on Ru with 6-31G basis was set for all other atoms. Assessment of bond lengths and angles between SXRD and DFT data demonstrated consistent values within expected ranges. Frontier molecular orbitals analysis and molecular electrostatic potential were also illustrated. The 2D fingerprint plot of Hirshfeld surface analysis reveals that H···H contact dominates the population with 38%. The interplay of intermolecular C–H···O hydrogen bond and C–H···π interactions were found to be effective in stabilizing the molecular structure. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to synthesize two different benzoxazines (Bz) monomers using bio-based and petroleum-based primary amines, respectively, and they have been compared to study their thermal and mechanical performances. Design/methodology/approach: A bio-based bisphenol, Divanillin (DiVa), was formed by reacting two moles of vanillin with one mole of ethylenediamine (EDA) which was then reacted firstly with paraformaldehyde and EDA to form the benzoxazine DiVa-EDA-Bz, and secondly with paraformaldehyde and furfuryl amine (FFA) to form the benzoxazine DiVa-FFA-Bz. The molecular structure and thermal properties of the benzoxazines were characterized by fourier transform infrared spectroscopy and nuclear magnetic resonance (1H,13C) spectroscopies, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The benzoxazines were further coated on mild steel panels to evaluate their mechanical properties and chemical resistance. Findings: The DSC results of DiVa-FFA-Bz showed two exothermic peaks related to crosslinking compared to the one in DiVa-EDA-Bz. The DiVa-FFA-Bz also showed a higher heat of polymerization than DiVa-EDA-Bz. The TGA results showed that DiVa-FFA-Bz exhibited higher thermal stability with a residual char of 54.10% than 43.24% for DiVa-EDA-Bz. The chemical resistance test results showed that DiVa-FFA-Bz showed better chemical resistance and mechanical properties due to its higher crosslinking density. Originality/value: This study shows the use of bio-based materials, vanillin and FFA, for synthesizing a benzoxazine resin and its application at high temperatures. [ABSTRACT FROM AUTHOR]

Boswellia serrata ole-gum-resin extracts (BSEs) are commonly used as food supplements, especially in osteoarthritis management. The quality standard is established by determining 11-keto-β-boswellic acid (KBA) and acetyl-11-keto-boswellic acid (AKBA) content using high-performance liquid chromatography (HPLC) or assessing the total boswellic acid (TBA) content by titrimetry. The limited geographical distribution of Boswellia species and increasing industrial demand could increase the risk of adulteration in Boswellia-containing products. In this study, 14 BSEs from commercial sources, used in food supplements, were analyzed in comparison with a USP Reference Standard extract. The KBA and AKBA content was determined by HPLC, whereas the TBA content was determined by titration. Targeted UHPLC-high-resolution mass spectrometry (HRMS) was applied to identify the carboxylic acid content in the samples. The 1H NMR spectra of extracts were also analyzed. Only two products met the criteria for KBA and AKBA content. Although, the TBA content complied with the expected amount, 10 extracts contained citric acid levels of 6–11% even though citric acid is not a cha-racteristic component of BSEs. Our results suggest undeclared addition of citric acid to comply with declared contents of TBA when using titration methods. Incorporation of citric acid to industrial samples – in order to alter the outcomes of the titration analysis – was demonstrated for the first time. [ABSTRACT FROM AUTHOR]

TATB and TATB-d6 were synthesized using phloroglucinol as raw material. Their molecular structure and micromorphology of them were well characterized by FTIR, NMR spectroscopy, XRD and FE-SEM. The thermal behaviors of these compounds were studied with TG-DSC, and the non-isothermal kinetic decomposition parameters of the two compounds were gained using the method of Friedman (FM). The apparent activation energy value of TATB-d6 was larger than that of TATB, which indicated the heat stabilization of deuterated TATB particles was improved. Finally, the thermal detonation critical temperatures of these two products were also calculated and discussed. [ABSTRACT FROM AUTHOR]

A new triterpenoid saponin (1), along with five known compounds (2–6), was isolated from Bupleurum marginatum Wall. ex DC, of which compounds 2–4 were obtained for the first time from this plant. The structures were confirmed by the analysis of 1D, 2D NMR, and HR-ESIMS data, and comparison with previous spectral data. Anti-liver fibrotic activities of the isolates were determined as proliferation inhibition of LPS-induced activation of HSC-T6 in vitro. [ABSTRACT FROM AUTHOR]

Two new triterpenes mayteneri A (1), mayteneri B (2), and seven known compounds (3-9) were isolated from stems of Maytenus hookeri Loes. The chemical structures of compounds 1 and 2 were established by 1D, 2D NMR, HRESIMS analysis, and calculating electronic circular dichroism (ECD). The structures of known compounds 3-9 were determined by comparison of their spectral with those reported. Compounds 4-7 showed significant inhibitory activity for NLRP3 inflammasome, with the IC50 values of 2.36–3.44 μM. [ABSTRACT FROM AUTHOR]

Two previously undescribed iridoid glycosides, 6'-O-trans-feruloyl-(4S,6R)-3,4-dihydro-3β-ethoxypaederoside (1) and 6'-O-trans-caffeoyl-(4S,6R)-3,4-dihydro-2'-O-3α-paederoside (2), were isolated from the 90% EtOH extract of the air dried aerial parts of Paederia Foetida. Structural elucidation of all the compounds was performed by spectral methods such as 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy. The two isolated iridoid glycosides were tested in vivo for their antinociceptive properties. As a result, 2 showed potent antinociceptive effect and its ID50 value (53.4 μmol/kg) was 2-fold less than those of the positive control drugs aspirin and acetaminophen. [ABSTRACT FROM AUTHOR]

Hericium erinaceus is a species of mushroom with high nutritional value that is used mainly as food in tropical countries. Phytochemical study of H. erinaceus led to the isolation of an undescribed compound, named as hericium VN (1), together with nine known compounds, 1-(2-formyl-1-pyrrolyl)butanoic acid (2), herierin III (3), 5′-(methylthio)adenosine (4), adenosine (5), nicotinic acid (6), (22E,24R)-5α,8α-epidioxyergosta-6,9(11),22-trien-3β-ol (7), 5α,8α-peroxycerevisterol (8), (22E,24R)-5α,8α-epidioxy-egosta-6,22-diene 3-O-β-D-glucopyranoside (9), and cerevisterol (10) based on extensive analyses of HR-ESI-MS, 1D and 2D NMR spectra. The absolute configuration of compound 1 was determined by experimental combined with calculated electronic circular dichroism spectra. Compound 7 exhibited cytotoxic effects against brain tumor cell line CCF-STTG1 with the IC50 value of 15.50 µM, compared to that of the positive control compound, doxorubicin, which showed IC50 value of 15.84 µM. [ABSTRACT FROM AUTHOR]

Phytochemical study on 90% ethanol extract from the green walnut husks of Juglans mandshurica Maxim. resulted into the isolation of three undescribed triterpenoids, juglansmanoids A–C (1–3). Structural elucidation of all the compounds were performed by spectral methods such as 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. The isolated components were evaluated in vitro for anti-hyaluronidase activities. As a result, triterpenoid 1 exhibited potent anti-hyaluronidase activity (IC50 = 9.78 μg/ml) three times more than the positive control drug oleanolic acid (IC50 = 40.12 μg/ml). [ABSTRACT FROM AUTHOR]

Nineteen isosteviol derivatives were designed and synthesized by C-16, C-19 and D-ring modifications of isosteviol. These compounds were screened for their cytotoxic activities against Hela and A549 cells in vitro. Among them, the inhibitory effect of compounds 3b and 16 on Hela cells was comparable to that of the positive control gefitinib, and the compounds 3b (IC50=7.84 ± 0.84 μM) and 7a (IC50=6.89 ± 0.33 μM) exhibited significant cytotoxicity superior to gefitinib (IC50=11.02 ± 3.27 μM) against A549 cells. [ABSTRACT FROM AUTHOR]

A new seco-A tirucallane triterpenoid named excelxylin A (1), along with two known seco-A triterpenoids (2–3), were isolated from the n-hexane extract of Dysoxylum excelsum (Spreng.) Blume ex G.Don stem bark. The structure and stereochemistry configuration of compounds 1–3 was established by NMR, IR, and HR-ESI-MS spectroscopic data analyses and comparison of their NMR data with literatures. The compounds exhibited the carbon framework for seco-A ring tirucallane triterpenoid, first reported in the Dysoxylum genus. All compounds were tested for their cytotoxicity against human cervical HeLa cells. [ABSTRACT FROM AUTHOR]

Thrombosis plays an important role in the occurrence and development of cardiovascular and cerebrovascular diseases that contribute to high mortality and morbidity in patients. L-(-)-Quebrachitol (QCT), a natural product, was first isolated from quebracho bark. It can inhibit PAF receptor and decrease gastric damage induced by indomethacin, as a drug against platelet aggregation. Here, five QCT derivatives were synthesized and investigated for their inhibitory effects on platelet aggregation. Among them, compound 3a showed anticoagulant effects comparable to aspirin, while compound 4b showed dose-independent inhibitory activities in rats that were stronger than aspirin. [ABSTRACT FROM AUTHOR]

Two new iridoid glycosides, piasezkiiosides A (1) and B (2), were isolated from aqueous extract of the whole plant of Rehmannia piasezkii. Their structures were established from the spectroscopic data, chemical transformation, and X-ray diffraction analysis. Compound 1 exhibited weak hepatoprotective activity against APAP-induced HepG2 cell damage. [ABSTRACT FROM AUTHOR]

A new steroid, 2a-oxa-2-oxo-5β-hydroxy-3,4-dinor-24-methylcholesta-22E-ene (1), together with 10 known ones (2–11), was isolated from the marine sponge Cliona sp. The structures of these compounds were determined by the spectroscopic methods (UV, IR, MS, and NMR) and X-ray diffraction analysis. Compound 1 was the third example of 3,4-dinorsteroid with a hemiketal at C-5 that was isolated from the natural source. In addition, the antibacterial activities of these compounds were also evaluated. However, none of them exhibited significant inhibition effects. [ABSTRACT FROM AUTHOR]

This article focuses on polyamide materials T1 and B1, and uses two types of fungi to conduct anti mold tests on them. It conducts in-depth exploration and research on the failure mechanism during the co cultivation process!* of fungi and polyamide. Through infrared spectroscopy analysis;, it was; found that mold growth can absorb oxygen from the outside, which can cause the methylene on the polyamide molecular chain to break and react with it to form carbonyl groups, causing changes in the internal structure of the molecule. Through UV spectroscopy and nuclear magnetic resonance analysis, it can be seen that due to the presence of highly reactive methylene structures on the internal molecular chains of polyamide, the color of polyamide and mold will change during the co cultivation process. It will react with the outside world to generate methylene free radicals, further react with oxygen to generate hydrogen peroxide, and then isomerize to generate carbonyl groups. The carbonyl groups then combine with other active groups to produce carbonyl imines. As a result, the conjugated chains on the polyamide molecular chains will increase, and the maximum absorption wavelength will be seen in the visible light region, which is macroscopically manifested as the color change of the polyamide material. Thermogravimetric analysis shows that fungi can obtain nutrients from the surface of polyamide for reproduction, and the surface structure will undergo significant damage and changes. Mechanical performance tests have shown that mold can cause a decrease in the tensile, bending, and impact properties of polyamide materials, and the two types of mold can cause different degrees of attenuation. [ABSTRACT FROM AUTHOR]

A series of palladium (II) and platinum (II) selenolate complexes have been isolated depending upon the nature of the phosphine ligand. The substitution reaction of [PdCl2(PPh3)2] with two equivalents of NaSeC5H3(5-Me)N resulted in the hexanuclear complex [Pd6Br0.87Cl1.13{2-SeC5H3(5-Me)N2}2(PPh3)6] (1a) whereas a chelated compound [Pt{κ-Se, κ-N: SeC5H3(5-Me)N}{SeC5H3(5-Me)N}(PPh3)] (1b) has been obtained in the case of [PtCl2(PPh3)2]. However, chelated phosphine as an ancillary ligand with a similar reaction by using [PtCl2(P∩P)] (P∩P = dppm, dppe) yielded cis-configured monomer [Pt{2-SeC5H3(5-Me)N}2(P∩P)]. The trinuclear complexes [M3(µ-Se)3(dppp)3]2+ [M = Pd (2d), Pt (2e)] were isolated by reactions of [MCl2(dppp)] (M = Pd, Pt) with NaSeC5H3(5-Me)N via facile cleavage of Se-C bond in presence of chlorinated solvents. All the synthesized complexes have been characterized by elemental analyses, 1H, 31P{1H}, 77Se{1H} NMR spectroscopy. The molecular structure of complexes [Pd6Br0.87Cl1.13{2-SeC5H3(5-Me)}2(PPh3)6] (1a) and [Pt{2-SeC5H3(5-Me)N}2(dppm)].C6H5CH3 (2a) were determined by single crystal X-ray diffraction analyses. [ABSTRACT FROM AUTHOR]

Five cationic ruthenium–arene complexes with the generic formula [Ru(SAc)(S2C·NHC)(p-cymene)](PF6) (5a–e) were prepared in almost quantitative yields using a straightforward one-pot, two-step experimental procedure starting from [RuCl2(p-cymene)]2, an imidazol(in)ium-2-dithiocarboxylate (NHC·CS2) zwitterion, KSAc, and KPF6. These half-sandwich compounds were fully characterized by various analytical techniques and the molecular structures of two of them were solved by X-ray diffraction analysis, which revealed the existence of an intramolecular chalcogen bond between the oxygen atom of the thioacetate ligand and a proximal sulfur atom of the dithiocarboxylate unit. DFT calculations showed that the C=S...O charge transfer amounted to 2.4 kcal mol−1. The dissolution of [Ru(SAc)(S2C·IMes)(p-cymene)](PF6) (5a) in moist DMSO-d6 at room temperature did not cause the dissociation of its sulfur ligands. Instead, p-cymene was slowly released to afford the 12-electron [Ru(SAc)(S2C·IMes)]+ cation that could be detected by mass spectrometry. Monitoring the solvolysis process by 1H NMR spectroscopy showed that more than 22 days were needed to fully decompose the starting ruthenium–arene complex. Compounds 5a–e exhibited a high antiproliferative activity against human glioma Hs683 and human lung carcinoma A549 cancer cells. In particular, the IMes derivative (5a) was the most potent compound of the series, achieving toxicities similar to those displayed by marketed platinum drugs. [ABSTRACT FROM AUTHOR]

In this research, a new Ag(I) complex, namely, [Ag(5‐chloro‐1H‐benzimidazole)2(NO3)], has been synthesized using the benzimidazole‐based ligand 5‐chloro‐1H‐benzimidazole (5ClBZ). Ag(I) complexes were characterized by elemental analysis, UV‐Vis, FT‐IR, and 1H NMR spectroscopy, and DFT analysis was used. The free ligand and its Ag(I) complexes were tried for their biochemical properties, including antioxidant and antidiabetic properties. To study the molecular structures of the title compounds, in silico ADME/Tox research was performed on the newly made complex and free ligand. The empirical guidelines relating to ADME were utilized to conduct molecular docking simulations and in‐depth drug‐likeness profiling. This was carried out to validate the conclusions and identify exact binding interactions. Based on the study's findings, it has been determined that these new compounds have significant potential as powerful therapeutic agents for controlling antioxidant and antidiabetic activities. [ABSTRACT FROM AUTHOR]

The reaction of [Ru2(CO)4(µ-H)(µ-PtBu2)(µ-Ph2PCH2PPh2)] (1) with the diazonium salts [PhN2]BF4 and [p-BrC6H4N2]BF4 in dichloromethane at T = 273 K was investigated. The oxidative addition afforded the products [Ru2(CO)4(µ-H)(µ-PtBu2)(µ-Ph2PCH2PPh2)(µ-N2Ph)]BF4 (2a) and [Ru2(CO)4(µ-H)(µ-PtBu2)(µ-Ph2PCH2PPh2)(µ-N2C6H4-p-Br)]BF4 (2b) in good yields. The products have been characterized by NMR and IR spectroscopy and mass spectrometry and the molecular structure of 2a has been determined by a single-crystal X-ray diffraction analysis (monoclinic, space group P21/m, Z = 2). [ABSTRACT FROM AUTHOR]

Sea cucumber-derived fungi have attracted much attention due to their capacity to produce an incredible variety of secondary metabolites. Genome-wide information on Aspergillus micronesiensis H39 obtained using third-generation sequencing technology (PacBio-SMRT) showed that the strain contains nonribosomal peptide synthetase (NRPS)-like gene clusters, which aroused our interest in mining its secondary metabolites. 11 known compounds (1–11), including two γ-aromatic butenolides (γ-AB) and five cytochalasans, were isolated from A. micronesiensis H39. The structures of the compounds were determined by NMR and ESIMS, and comparison with those reported in the literature. From the perspective of biogenetic origins, the γ-butyrolactone core of compounds 1 and 2 was assembled by NRPS-like enzyme. All of the obtained compounds showed no inhibitory activity against drug-resistant bacteria and fungi, as well as compounds 1 and 2 had no anti-angiogenic activity against zebrafish. [ABSTRACT FROM AUTHOR]

The Discretizable Molecular Distance Geometry Problem (DMDGP) plays a key role in the construction of three-dimensional molecular structures from interatomic distances acquired through nuclear magnetic resonance (NMR) spectroscopy, with the primary objective of validating a sequence of distance constraints related to NMR data. This article addresses the escalating complexity of the DMDGP encountered with larger and more flexible molecules by introducing a novel strategy via the Molecular Ordered Covering Problem, which optimizes the ordering of distance constraints to improve computational efficiency in DMDGP resolution. This approach utilizes a specialized Branch-and-Bound (BB) algorithm, tested on both synthetic and actual protein structures from the protein data bank. Our analysis demonstrates the efficacy of the previously proposed greedy heuristic in managing complex molecular scenarios, highlighting the BB algorithm's utility as a validation mechanism. This research contributes to ongoing efforts in molecular structure analysis, with possible implications for areas such as protein folding, drug design, and molecular modeling. [ABSTRACT FROM AUTHOR]

In the context of our ongoing studies on chromane derivatives as inhibitors of the salicylate synthase from M. tuberculosis, we isolated a new, unexpected compound from the cyclization of 3-(propargyloxy)-5-benzyloxy-benzoic acid methyl ester. Its molecular structure was elucidated by means of 1D and 2D NMR analyses, FT-IR, ESI-MS, and HRMS. [ABSTRACT FROM AUTHOR]

The process of development and optimization of anticancer drugs entails the design, synthesis, and elucidating of a diverse range of compounds. Among these are organotin(IV) dithiocarbamate metal complexes, which offer promising potential as anti-cancer agents. Recent studies have underscored the potential of these complexes to exert encouraging anti-proliferative activities against cancer cells, which can be attributed to their distinctive molecular structures and interactions with malignant tissues. This study aimed to refine the chemical constitution of Ph2Sn (N-ethyl-N-benzyldithiocarbamate) through the application of cutting-edge analytical methods, including elemental and spectral analysis (infrared (IR) and NMR spectroscopy). Following optimization, the bioactivity of the newly designed compounds was evaluated on A549 human lung cancer cells utilizing standardized MTT assays to bring a better understanding of the structureactivity relationship (SAR). Our results indicate that these compounds display augmented cytotoxicity vis-à-vis current platinum-based chemotherapeutics, cisplatin, thereby highlighting their potential as an innovative alternative to conventional anti-cancer therapies. [ABSTRACT FROM AUTHOR]

Background: The plant roots excrete a large number of organic compounds into the soil. The rhizosphere, a thin soil zone around the roots, is a hotspot for microbial activity, making it a crucial component of the soil ecosystem. Secondary metabolites produced by rhizospheric Sphingomonas sanguinis DM have sparked significant curiosity in investigating their possible biological impacts. Methods: A bacterial strain has been isolated from the rhizosphere of Datura metel. The bacterium's identification, fermentation, and working up have been outlined. The ethyl acetate fraction of the propagated culture media of Sphingomonas sanguinis DM was fractioned and purified using various chromatographic techniques. The characterization of the isolated compounds was accomplished through the utilization of various spectroscopic techniques, such as UV, MS, 1D, and 2D-NMR. Furthermore, the evaluation of their antimicrobial activity was conducted using the agar well diffusion method, while cytotoxicity was assessed using the MTT test. Results: The extract from Sphingomonas sanguinis DM provided two distinct compounds: n-dibutyl phthalic acid (1) and Bis (2-methyl heptyl) phthalate (2) within its ethyl acetate fraction. Furthermore, the 16S rRNA gene sequence of Sphingomonas sanguinis DM has been registered under the NCBI GenBank database with the accession number PP422198. The bacterial extract exhibited its effect against gram-positive bacteria, inhibiting Streptococcus mutans (12.6 ± 0.6 mm) and Staphylococcus aureus (10.6 ± 0.6 mm) compared to standard antibiotics. Conversely, compound 1 showed a considerable effect against phytopathogenic fungi such as Alternaria alternate (56.3 ± 10.6 mm) and Fusarium oxysporum (21.3 ± 1.5 mm) with a MIC value of 17.5 µg/mL. However, it was slightly active against Klebsiella pneumonia (11.0 ± 1.0 mm). Furthermore, compound 2 was the most active metabolite, having a significant antimicrobial efficacy against Rhizoctonia solani (63.6 ± 1.1 mm), Pseudomonas aeruginosa (16.7 ± 0.6 mm), and Alternaria alternate (20.3 ± 0.6 mm) with MIC value at 15 µg/mL. In addition, compound 2 exhibited the most potency against hepatocellular (HepG-2) and skin (A-431) carcinoma cell lines with IC50 values of 107.16 µg/mL and 111.36 µg/mL, respectively. Conclusion: Sphingomonas sanguinis DM, a rhizosphere bacterium of Datura metel, was studied for its phytochemical and biological characteristics, resulting in the identification of two compounds with moderate antimicrobial and cytotoxic activities. [ABSTRACT FROM AUTHOR]

Existing modelling tools, developed to aid the design of efficient molecular wires and to better understand their charge‐transport behaviour and mechanism, have limitations in accuracy and computational cost. Further research is required to develop faster and more precise methods that can yield information on how charge transport properties are impacted by changes in the chemical structure of a molecular wire. In this study, we report a clear semilogarithmic correlation between charge transport efficiency and nuclear magnetic resonance chemical shifts in multiple series of molecular wires, also accounting for the presence of chemical substituents. The NMR data was used to inform a simple tight‐binding model that accurately captures the experimental single‐molecule conductance values, especially useful in this case as more sophisticated density functional theory calculations fail due to inherent limitations. Our study demonstrates the potential of NMR spectroscopy as a valuable tool for characterising, rationalising, and gaining additional insights on the charge transport properties of single‐molecule junctions. [ABSTRACT FROM AUTHOR]

The salt metathesis reaction of dipotassium germacyclopentadienediide with aluminum(III) dichlorides provides either half‐sandwich alumole complexes of germanium(II) or aluminylene germole complexes. Their molecular structure and the delocalized bonding situation, revealed by density functional theory (DFT) calculations, are equally described as isomeric aluminagerma[5]pyramidanes with either the germanium or the aluminum atom in the apical position of the pentagonal pyramid. The product formation and the selectivity of the reaction depends on the third substituent of the aluminum dichloride. Aryl‐substituents favor the formation of alumole complexes and Cp*‐substituents that of the isomeric germole complexes. With amino‐substituents at the aluminum atom mixtures of both isomers are formed and the positional exchange of the two heteroatoms is shown by NMR spectroscopy. The alumole complexes of germanium(II) undergo facile reductive elimination of germanium and form the corresponding alumoles. [ABSTRACT FROM AUTHOR]

Efficient and robust analytical methods are needed to improve the identification and subsequent regulation of new psychoactive substances (NPS). NMR spectroscopy is a unique method able to determine the structure of small molecules such as NPS even in mixtures. However, high‐field NMR analysis is associated with expensive purchase and maintenance costs. For more than a decade, compact NMR spectrometers have changed this paradigm. It was recently shown that a dedicated analytical workflow combining compact NMR and databases could identify the molecular structure of NPS, in spite of the lower spectral dispersion and sensitivity of compact spectrometers. This approach relies on 1H‐13C HSQC to both recognize NPS and elucidate the structure of unknown substances. Still, its performance is limited by the need to compromise between resolution and experiment time. Here, we show that this strategy can be significantly improved by implementing non‐uniform sampling (NUS) to improve spectral resolution in the 13C dimension of HSQC at no cost in terms of experiment time. Gains in the range of 3 to 4 in resolution are achieved for pure NPS and for a mixture. Finally, 2D HSQC with NUS was applied to improve the identification of NPS with the assistance of databases. The resulting method appears as a useful tool for the characterization of NPS in mixtures, which is essential for forensic laboratories. [ABSTRACT FROM AUTHOR]

In this paper, a new type of Gemini surfactant was synthesized by esterification reaction of phthalic anhydride and fatty alcohol polyoxyethylene ether to improve the pollution problem and achieve the purpose of reservoir restoration in the near-wellbore area. The target product was characterized by infrared spectroscopy and hydrogen nuclear magnetic resonance spectroscopy. The ability of Gemini surfactant to reduce boundary surface tension, wettability, dispersion, viscosity reduction, oil washing and core damage recovery were studied. Gemini surfactant The critical micelle concentration (cmc) and the corresponding γ-cmc of Gemini surfactant are 26 mg/L and 30.26 μN/m, respectively. Gemini surfactant has a good ability to wash oil, which effectively reduce the interfacial tension of oil and water. At the same time, the benzene ring in the molecular structure of Gemini surfactant dissolve the organic matter in the pollution source, and the core permeability could be restored. [ABSTRACT FROM AUTHOR]

The use of modern spectroscopic methods of analysis, which provide extensive information on the chemical nature of substances, significantly expands our understanding of the molecular composition and properties of soil organic matter (SOM) and its transformation and stabilization processes in various ecosystems and geochemical conditions. The aim of this review is to identify and analyze studies related to the application of nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy techniques to study the molecular composition and transformation of organic matter in virgin and arable soils. This article is mainly based on three research questions: (1) Which NMR spectroscopy techniques are used to study SOM, and what are their disadvantages and advantages? (2) How is the NMR spectroscopy technique used to study the molecular structure of different pools of SOM? (3) How is ESR spectroscopy used in SOM chemistry, and what are its advantages and limitations? Relevant studies published between 1996 and 2024 were searched in four databases: eLIBRARY, MDPI, ScienceDirect and Springer. We excluded non-English-language articles, review articles, non-peer-reviewed articles and other non-article publications, as well as publications that were not available according to the search protocols. Exclusion criteria for articles were studies that used NMR and EPR techniques to study non-SOM and where these techniques were not the primary methods. Our scoping review found that both solid-state and solution-state NMR spectroscopy are commonly used to study the structure of soil organic matter (SOM). Solution-phase NMR is particularly useful for studying soluble SOM components of a low molecular weight, whereas solid-phase NMR offers advantages such as higher 13C atom concentration for stronger signals and faster analysis time. However, solution-phase NMR has limitations including sample insolubility, potential signal aggregation and reduced sensitivity and resolution. Solid-state NMR is better at detecting non-protonated carbon atoms and identifying heterogeneous regions within structures. EPR spectroscopy, on the other hand, offers significant advantages in experimental biochemistry due to its high sensitivity and ability to provide detailed information about substances containing free radicals (FRs), aiding in the assessment of their reactivity and transformations. Understanding the FR structure in biopolymers can help to study the formation and transformation of SOM. The integration of two- and three-dimensional NMR spectroscopy with other analytical methods, such as chromatography, mass spectrometry, etc., provides a more comprehensive approach to deciphering the complex composition of SOM than one-dimensional techniques alone. [ABSTRACT FROM AUTHOR]

Alkaloids are among the most important and best-known secondary metabolites as sources of new drugs from medicinal plants and marine organisms. A phytochemical investigation of the whole plant of Crinum asiaticum var. sinicum resulted in the isolation of seven alkaloids (1–7), including one new dimeric compound, bis-(-)-8-demethylmaritidine (1). Their structures were elucidated using NMR and HR-ESI-MS. The absolute configuration of new compound 1 was established by circular dichroism spectroscopy. All isolated compounds were evaluated for their inhibitory effects on acetylcholinesterase (AChE) activity in vitro. Among them, compound 1 exhibited the most potent AChE inhibition. Moreover, molecular docking and molecular dynamics simulations were carried out for the most active compound to investigate their binding interactions and dynamics behavior of the AChE protein-ligand complex. Therefore, compound 1 may be a potential candidate for effectively treating Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Two oxygenated ergostane-type steroids including one new compound, 3β-hydroxy-5α,6β-methoxyergosta-7,22-dien-15-one (1) along with a known analogue ergosta-6,22-dien-3β,5α,8α-triol (2) were isolated from the crude extracts of the marine sponge-derived fungus Aspergillus sp. Their structures were elucidated on the basis of combined NMR and MS spectroscopic methods. Compound 1 was a marine ergostane-type steroid with two methoxy groups at C-5 and C-6, respectively. These oxygenated ergostane-type steroids were evaluated for their antibacterial activities against human or aquatic pathogens. Among them, compound 1 exhibited antibacterial activity against Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

A phytochemical investigation on the 80% EtOH extract of the fruiting bodies of Ganoderma tsugae resulted into the isolation of two previously undescribed lanostane triterpenoids, 7,11-dioxo-3β-acetyloxy-26,27-dihydroxy-lanosta-8,24-diene (1) and 7,20-dioxo-3β-acetyloxy-11β,15α-dihydroxy-22,23,24,25,26,27-hexanorlanosta-8-ene (2), togeher with one known lanostane triterpenoid ganodermanontriol (3). Structural elucidation of all the compounds were performed by spectral methods such as 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy. All the triterpenoids were in vitro evaluated for their antibacterial activities against six pathogenic microorganisms. Compound 3 exhibited some activities against three Gram positive bacteria with MIC values less than 30 μg/ml. [ABSTRACT FROM AUTHOR]

New dammarane-type triterpenoid saponin, named 22(R)-notoginsenoside Ab1 (1), together with thirteen known dammarane-type triterpenoid saponins (2-14) was isolated from the EtOH extract of black ginseng and their structures were elucidated on the basis of one- and two-dimensional NMR (including 1H-NMR, 13C-NMR, HSQC, HMBC, ROESY) and calculated ECD. Among them, compounds 1-2 and 6-8 were isolated for the first time from ginseng and black ginseng. Besides, the absolute structure of 22(R)- and 22(S)- notoginsenoside Ab1 were distinguished by ECD for the first time. [ABSTRACT FROM AUTHOR]

Background: Dioscorea bulbifera Linn. has been used for wound care in Thailand. However, a comprehensive evaluation of its antibacterial activity is required. This study aimed to investigate the antibacterial efficacy of D. bulbifera extract against skin-associated bacteria and isolate and characterize its active antibacterial agent, flavanthrinin. Methods: Air-dried bulbils of D. bulbifera were pulverised and extracted with hexane, dichloromethane, ethyl acetate, methanol, ethanol, and distilled water; vacuum filtered; concentrated; freeze-dried; and stored at -20 ºC. Antibacterial activity of the extracts was assessed using microdilution techniques against several skin-associated bacteria. Thin-layer chromatography (TLC) bioautography was used to identify the active compounds in the extract, which were fractionated by column chromatography and purified by preparative TLC. The chemical structures of the purified compounds were analysed using nuclear magnetic resonance (NMR). The cytotoxicity of the extract and its active compounds was evaluated in Vero cells. Results: The ethyl acetate extract exhibited distinct inhibition zones against bacteria compared to other extracts. Therefore, the ethyl acetate extract of D. bulbifera in the ethyl acetate layer was used for subsequent analyses. D. bulbifera extract exhibited antibacterial activity, with minimum inhibitory concentrations (MICs) of 0.78–1.56 mg/mL. An active compound, identified through TLC-bioautography, demonstrated enhanced antibacterial activity, with MICs of 0.02–0.78 mg/mL. NMR analysis identified this bioactive compound as flavanthrinin. Both D. bulbifera extract and flavanthrinin-containing fraction demonstrated potent antibacterial activity against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and S. epidermidis. The flavanthrinin containing fraction demonstrated low cytotoxicity against Vero cells, showing CC50 values of 0.41 ± 0.03 mg/mL. These values are lower than the MIC value, indicating that this fraction is safer than the initial ethyl acetate extract. Conclusions: Dioscorea bulbifera extract and its bioactive component flavanthrinin demonstrated significant antibacterial activity against the skin-associated bacteria Staphylococci, including MRSA. Flavanthrinin has potential as a complementary therapeutic agent for managing skin infections owing to its potent antibacterial effects and low cytotoxicity. [ABSTRACT FROM AUTHOR]

The attempted synthesis of [{Carb}BaPPh2] (1) showed this barium-phosphide and its thf adducts, 1·thf and 1·(thf)2, to be unstable in solution. Our strategy to circumvent the fragility of these compounds involved the use of phosphinoboranes HPPh2·BH3 and HPPh2·B(C6F5)3 instead of HPPh2. This allowed for the synthesis of [{Carb}Ae{PPh2·BH3}] (Ae = Ba, 2; Ca, 3), [{Carb}Ca{(H3B)2PPh2}·(thf)] (4), [{Carb}Ba{PPh2·B(C6F5)3}] (5), [{Carb}Ba{O(B(C6F5)3)CH2CH2CH2CH2PPh2}·thf] (6), [Ba{O(B(C6F5)3)CH2CH2CH2CH2PPh2}2·(thf)1.5] (7) and [Ba{PPh2·B(C6F5)3}2·(thp)2] (8) that were characterised by multinuclear NMR spectroscopy (thp = tetrahydropyran). The molecular structures of 4, 6 and 8 were validated by X-ray diffraction crystallography, which revealed the presence of Ba⋯F stabilizing interactions (ca. 9 kcal mol−1) in the fluorine-containing compounds. Compounds 6 and 7 were obtained upon ring-opening of thf by their respective precursors, 5 and the in situ prepared [Ba{PPh2·B(C6F5)3}2]n. By contrast, thp does not undergo ring-opening under the same conditions but affords clean formation of 8. DFT analysis did not highlight any specific weakness of the Ba–P bond in 1·(thf)2. The instability of this compound is instead thought to stem from the high energy of its HOMO, which contains the non-conjugated P lone pair and features significant nucleophilic reactivity. [ABSTRACT FROM AUTHOR]