Mackinnonmccaffrey3672

Burchellin and its analogues are a class of neolignan natural products containing a rare core with three contiguous stereogenic centers. In previous reports, racemic burchellin was synthesized without accessing each of the enantiomers. In this paper, a concise and efficient total synthetic route to divergently access the enantiomers of burchellin and those of its 1'-epi-diastereoisomer over six steps for each is disclosed, where each of the enantiomers was obtained by preparative chiral phase HPLC purification. The key steps include the construction of a 2,3-dihydrobenzofuran moiety by two Claisen rearrangements and a one-step rearrangement/cyclization and subsequent tandem ester hydrolysis/oxy-Cope rearrangement/methylation to furnish the basic skeleton of burchellin. The structures and absolute configurations of the four stereoisomers were determined using spectroscopic data analyses and comparison of experimental and calculated electronic circular dichroism data. These stereoisomers were found to have potent antiviral effects against coxsackie virus B3, and is the first time that bioactivity has been reported for these compounds.We find that the use of Au substrate allows fast, self-limited WS2 monolayer growth using a simple sequential exposure pattern of low cost, low toxicity precursors, namely tungsten hexacarbonyl and dimethylsulfide (DMS). We use this model reaction system to fingerprint the technologically important metal organic chemical vapour deposition process by operando X-ray photoelectron spectroscopy (XPS) to address the current lack of understanding of the underlying fundamental growth mechanisms for WS2 and related transition metal dichalcogenides. Au effectively promotes the sulfidation of W with simple organosulfides, enabling WS2 growth with low DMS pressure ( less then 1 mbar) and a suppression of carbon contamination of as-grown WS2, which to date has been a major challenge with this precursor chemistry. Full WS2 coverage can be achieved by one exposure cycle of 10 minutes at 700 °C. We discuss our findings in the wider context of previous literature on heterogeneous catalysis, 2D crystal growth, and overlapping process technologies such as atomic layer deposition (ALD) and direct metal conversion, linking to future integrated manufacturing processes for transition metal dichalcogenide layers.Carbon nanobubbles are regarded as one of the most promising carbon-based anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), with significantly improved capacity and superior cycling stability. The wet-chemistry method is a cost-effective and readily scalable method of preparing carbon nanobubbles when compared to common pyrolysis, but balancing the relationship between high capacity and low initial coulombic efficiency still remains challenging. Herein, we present a solution-polymerization method associated with a removable template to realize the controllable synthesis of N-doped carbon nanobubbles (NCN). The obtained NCN material delivers impressive high specific capacity as an anode for both LIBs and SIBs (799 mA h g-1 at 0.8 A g-1 for 385 cycles in LIBs; 248 mA h g-1 at 0.3 A g-1 for 200 cycles in SIBs). Meanwhile, the NCN anode exhibits an initial coulombic efficiency of nearly 80% for both LIBs and SIBs, which is ascribed to the moderate specific surface area and rational structure design.Covering 2007 to 2020 Selaginellins are a small group of pigments exclusively found in the ancient genus Selaginella. Since the first report of selaginellin from S. sinensis in 2007, more than 110 selaginellins with diverse polyphenolic skeletons have been reported. LC-2 This review provides extensive coverage of the selaginellins discovered from 2007 to 2020, including 61 natural ones and 52 synthetic analogues. The isolation, chemical structures, plausible biosynthetic pathways, bioactivity, and total synthesis of these selaginellins have been summarized for the first time, and this highlights the fact that the vast uninvestigated Selaginella species may serve as a potential treasure trove of chemically diverse selaginellins waiting to be discovered.Second near-infrared (NIR-II) window responsive phototheranostic agents have a precise spatiotemporal potential for the diagnosis and treatment of cancer. In this study, a full-spectrum responsive ZrO2-based phototheranostic agent was found to achieve NIR-II photoacoustic (PA) imaging-guided tumour-targeting phototherapy. Initially, the ZrO2-based phototheranostic agent was fabricated through NaBH4 reduction to form boron-doped oxygen-deficient zirconia (ZrO2-x-B), an amino-functionalised SiO2 shell and a further covalent connection with hyaluronic acid (HA), namely, ZrO2-x-B@SiO2-HA. In the ZrO2-x-B@SiO2-HA system, the oxygen vacancy and boron doping resulted in full-spectrum absorption, enabling a high NIR-II photothermal conversion, high-resolution PA imaging ability and a remarkable production of reactive oxygen species (ROS). The surface modification of HA provided ZrO2-x-B@SiO2-HA with water dispersibility and a targeting capability for CD44 overexpressed cancer cells. Furthermore, in vitro and in vivo experiments showed that NIR-II activated ZrO2-x-B@SiO2-HA had a targeted photothermal/photodynamic effect for cancer elimination under the real-time guidance of NIR-II PAs. Hence, ZrO2-x-B@SiO2-HA displays a precise NIR-II radiation-activated phototheranostic potential for PA imaging-guided cancer-targeting photothermal/photodynamic therapy.Though a large amount of literature has been reported on outlining the biological significance of zinc(ii) Schiff base complexes, yet none of them have explored the influence of nuclearity on their properties. This report elaborates the targeted syntheses of two different hemi-salen ligands for their ability to produce Zn(ii)-complexes with different nuclearity. Herein, one dimeric, [Zn2L12(N3)2] (1) and one trimeric [Zn3L22(N3)4] (2) [HL1 = (2-(((2-(diethylamino)ethyl)imino)methyl)phenol, HL2 = 2-(((3-(dimethylamino)-2,2-dimethylpropyl)imino)methyl)-6-methoxyphenol] complexes of hemi-salen ligands have been thoroughly screened for various biological studies including cytotoxic assay, DNA/protein-complex interplay, fluorescence imaging, and antibacterial pathogen tests. The trimer features the IC50 value of 9.651 ± 0.026 μM against the HeLa cancer cell line, one of the best figure by any Zn(ii) hemi-salen complex to date. How the nuclearity dependency affects the supramolecular interactions is also a key point of interest in this study. The compounds exhibit strong DNA binding affinity and the dimer 1 predominantly binds to the minor grooves of DNA (binding energy = -5.8 kcal mol-1), whereas trimer 2 prefers the intercalative mode (binding energy = -7.1 kcal mol-1) in contrast to groove binding (binding energy = -6.2 kcal mol-1). The atypical phenomenon behind the conformational changes of biomolecules by these zinc complexes has been investigated through experimental procedures and further corroborated theoretically. Apart from this, it has been found that even at very low concentration (≤10 μM) of the ligand, HL1 and complexes can be effective for live cell imaging. It is worth mentioning that HL1 could be useful for the specific staining of the cell cytoplasm. Furthermore, the complexes have shown promising anti-bacterial activity; thus, they can be convenient for multiple biological applications.Developing a mass spectrometry-based assay for the ovarian cancer biomarker CA125 (MUC16) is a desirable goal, because it may enable detection of molecular regions that are not recognized by antibodies and are therefore analytically silent in the current immunoassay. Additionally, the ability to characterize the CA125 proteoforms expressed by individuals may offer clinical insight. Enrichment of CA125 from malignant ascites may provide a high-quality source of this important ovarian cancer biomarker, but a reliable strategy for such enrichment is currently lacking. Beginning with crude ascites isolated from three individual patients with high grade serous ovarian cancer, we enriched for MUC16 using filtration, ion exchange, and size exclusion chromatography and then performed bottom-up proteomics on the isolated proteins. This approach of enrichment and analysis reveals that the peptides detected via mass spectrometry map to the SEA domain and C-loop regions within the tandem repeat domains of CA125 and that peptide abundance correlates with clinical CA125 counts.Here we evaluate a quick and easy tool for determination of epitope configuration using immunocapture and liquid chromatography mass spectrometry (LC-MS) subsequent to pre-treatment of the target protein to disrupt its three-dimensional structure. The approach can be a valuable screening tool to identify antibodies that can be used in peptide capture by anti-protein antibodies. The experimental set-up was established using seven monoclonal antibodies (mAbs) with known linear or conformational epitope recognition. The mAbs were developed to target either of the two biomarkers, progastrin releasing peptide (ProGRP) or human chorionic gonadotropin (hCG). Best coherence with established epitope configuration was seen when using both denaturation, reduction and alkylation as pre-treatment method of the proteins (≥70% reduction in MS signal intensity compared to control) prior to immunocapture and LC-MS determination. The final method was used to determine the epitope configuration of four anti-thyroglobulin mAbs with unknown epitope configuration; all four mAbs showed configurational epitope recognition. These results were also supported by western blots of native, and reduced and alkylated protein using three of the evaluated mAbs, and by analysis native, and reduced and alkylated protein in a routine immunofluorometric assay employing the four evaluated antibodies.Three copper(ii) complexes, [Cu(L1)(NCS)]n (1), [Cu(L1)(N3)]n (2) and [Cu(L2)(N3)] (3) were synthesized from one Schiff base ligand and one reduced Schiff base ligand, (E)-4-chloro-2-[(2-propylaminoethylimino)methyl]phenol (HL1) and 4-chloro-2-[(2-(propylaminoethylamino) methyl]phenol (HL2), respectively. All complexes were characterized by various physicochemical studies, such as FT-IR, UV-Vis, ESI-MS, EPR and single crystal X-ray diffraction. Complexes 1 and 2 have 1D polymeric chain-like structures bridging through thiocyanate and azide anions, whereas complex 3 has a mononuclear structure in the solid state. All the complexes are active towards mimicking two well-known proteins, phosphatase and phenoxazinone synthase, using the disodium salt of 4-nitrophenylphosphate (4-NPP) and 2-aminophenol (OAP) as the substrate in DMF medium. Complexes 2 and 3 show the highest activity towards phosphatase and phenoxazinone synthase activity with kcat values of 22.6 s-1 and 134.4 h-1, respectively. EPR studies confirmed that for complex 1, the OAP oxidation goes through the generation of an organic radical at g = 1.99, which is due to an imine radical formation, whereas the metal center redox pathway is followed for complex 3. Extensive DFT calculations have been performed for both catalytic studies to put forward the most probable mechanistic pathways.