Divergent synthesis of complex withanolides enabled by a scalable route and late-stage functionalization.

Withanolides are a group of naturally occurring C28 steroids based on an ergostane skeleton. They have a high degree of polyoxygenation, and the abundance of O-functional groups has enabled various natural alterations to both the carbocyclic skeleton and the side chain. Consequently, these molecules have intricate structural features that lead to their highly varied display of biological activities including anticancer, anti-inflammatory, and immunomodulating properties. Despite being intriguing leads for further discovery research, synthetic access to the withanolides remains highly challenging-compounds for current biological research are mainly isolated from plants, often inefficiently. Here, we report the divergent synthesis of 11 withanolides in 12 to 20 steps, enabled by a gram-scale route and a series of late-stage functionalizations, most notably a bioinspired photooxygenation-allylic hydroperoxide rearrangement sequence. This approach enables further biological research disconnected from a reliance on minute quantities of the parent natural products or their simple derivatives.

Activation of Einstein-Podolsky-Rosen steering sharing with unsharp nonlocal measurements.

Einstein-Podolsky-Rosen (EPR) steering is commonly shared among multiple observers by utilizing unsharp measurements. Nevertheless, their usage is restricted to local measurements and does not encompass all nonlocal measurement-based cases. In this work, a method for finding beneficial local measurement settings has been expanded to include nonlocal measurement cases. This method is applicable for any bipartite state and offers benefits even in scenarios with a high number of measurement settings. Using the Greenberger-Horne-Zeilinger state as an illustration, we show that employing unsharp nonlocal measurements can activate the phenomenon of steering sharing in contrast to using local measurements. Furthermore, our findings demonstrate that nonlocal measurements with unequal strength possess a greater activation capability compared to those with equal strength. Our activation method generates fresh concepts for conservation and recycling quantum resources.

Asymmetric synthesis of sulfoximines, sulfonimidoyl fluorides and sulfonimidamides enabled by an enantiopure bifunctional S(VI) reagent.

An increased interest to expand three-dimensional chemical space for the design of new materials and medicines has created a demand for isosteric replacement groups of commonly used molecular functionality. The structural and chemical properties of chiral S(VI) functional groups provide unique spatial and electronic features compared with their achiral sulfur- and carbon-based counterparts. Manipulation of the S(VI) centre to introduce structural variation with stereochemical control has remained a synthetic challenge. The stability of sulfonimidoyl fluorides and the efficiency of sulfur fluorine exchange chemistry has enabled the development of the enantiopure bifunctional S(VI) transfer reagent t-BuSF to overcome current synthetic limitations. Here, we disclose a reagent platform that serves as a chiral sulfur fluorine exchange template for the rapid asymmetric synthesis of over 70 sulfoximines, sulfonimidoyl fluorides and sulfonimidamides with excellent enantiomeric excess and good overall yields. Furthermore, the practical utility of the bifunctional S(VI) transfer reagent was demonstrated in the syntheses of enantiopure pharmaceutical intermediates and analogues.

Triazole-modified Ru-carbene complexes: A valid olefin metathesis pre-catalyst for dynamic covalent chemistry via C=C bond formation.

The 1,2,3-triazole coordinated ruthenium carbene complexes (TA-Ru) were reported for the first time as a new class of modified Grubbs catalyst to achieve challenging olefin metathesis at higher temperatures without catalyst decomposition. Previously reported N-tethered Ru-carbene complexes all suffered from rapid cis/trans isomerization, causing significantly reduced catalyst reactivity. These new TA-Ru complexes hold the active trans-dichloro conformation even at 80 °C, allowing effective olefin metathesis for challenging substrates. With this new TA-Ru catalyst, cross-metathesis (CM), ring-closing metathesis (RCM) and dynamic covalent chemistry (DCvC) were achieved. Excitingly, the reactivity of TA-Ru prevails all previously reported N-coordinated Ru-carbene precatalysts, Grubbs II, and Hoveyda-Grubbs, making the TA-Ru a transformative catalytic system in olefin catalysis.

Asymmetric Hydrative Aldol Reaction (HAR) via Vinyl-Gold Promoted Intermolecular Ynamide Addition to Aldehydes.

Herein, we reported an intermolecular asymmetric hydrative aldol reaction through vinyl-gold intermediate under ambient conditions. This tandem alkyne hydration and sequential nucleophilic addition afforded a "base-free" approach to ß-hydroxy amides with high efficiency (up to 95 % yields, >50 examples). Vinyl gold intermediate was applied as reactive nucleophile and Fe(acac)3 was used as the critical co-catalyst to prevent undesired protodeauration, allowing this transformation to proceed under mild conditions with good functional group tolerance and excellent stereoselectivity (>20 : 1 d.r. and up to 99 % ee).

Application of Monocyte-to-Albumin Ratio and Neutrophil Percentage-to-Hemoglobin Ratio on Distinguishing Non-Small Cell Lung Cancer Patients from Healthy Subjects.

Objective: This study aims at assessing the potential benefits of observation of monocyte-to-albumin ratio (MAR) and neutrophil percentage-to-hemoglobin ratio (NPHR) in the detection of non-small cell lung cancer (NSCLC). Methods: This study retrospectively involved 195 NSCLC patients and 204 healthy volunteers. The correlations between the clinicopathological characteristics of NSCLC and the two ratios including MAR and NPHR were assessed. The diagnostic efficiency of NSCLC patients by MAR and NPHR, alone or in combination with carcinoembryonic antigen (CEA), was assessed by receiver operating characteristic (ROC) curve. The risk factors for NSCLC were analyzed with binary logistic regression. Results: Compared to healthy controls, the levels of MAR and NPHR in NSCLC patients were elevated. MAR and NPHR were related to clinicopathologic characteristics and increased significantly along with the progression of NSCLC. The area under the curve (AUC) for 95% confidence interval (95% CI) of MAR and NPHR in the diagnosis of NSCLC was 0.812 (0.769-0.854) and 0.724 (0.675-0.774), respectively. The combination of MAR, NPHR, and CEA achieved the highest diagnostic utility compared to each individually or combined markers (AUC, 0.86; 95% CI, 0.824-0.896; sensitivity, 72.8%; specificity, 87.3%). Further analysis showed that MAR combined with NPHR presented the potential to detect early-stage (IA-IIB) NSCLC (AUC, 0.794; 95% CI, 0.743-0.845; sensitivity, 55.1%; specificity, 87.7%). The result indicated that MAR and NPHR might be risk factors for NSCLC. Conclusion: MAR and NPHR could be novel and effective auxiliary indexes in the detection of NSCLC, especially when combined with CEA.

Non-canonical functions of SNAIL drive context-specific cancer progression.

SNAIL is a key transcriptional regulator in embryonic development and cancer. Its effects in physiology and disease are believed to be linked to its role as a master regulator of epithelial-to-mesenchymal transition (EMT). Here, we report EMT-independent oncogenic SNAIL functions in cancer. Using genetic models, we systematically interrogated SNAIL effects in various oncogenic backgrounds and tissue types. SNAIL-related phenotypes displayed remarkable tissue- and genetic context-dependencies, ranging from protective effects as observed in KRAS- or WNT-driven intestinal cancers, to dramatic acceleration of tumorigenesis, as shown in KRAS-induced pancreatic cancer. Unexpectedly, SNAIL-driven oncogenesis was not associated with E-cadherin downregulation or induction of an overt EMT program. Instead, we show that SNAIL induces bypass of senescence and cell cycle progression through p16INK4A-independent inactivation of the Retinoblastoma (RB)-restriction checkpoint. Collectively, our work identifies non-canonical EMT-independent functions of SNAIL and unravel its complex context-dependent role in cancer.

Additional diagnostic value of the monocyte to red blood cell count ratio and the product of lymphocyte count and albumin concentration in lung cancer management.

The present study aimed to evaluate the potential of the monocyte to red blood cell count ratio (MRR), the neutrophil to red blood cell count ratio (NRR), the lymphocyte to red blood cell count ratio (LRR) and the product of lymphocyte count and albumin concentration (LA) for the diagnosis of lung cancer. The cases of 216 patients with newly diagnosed lung cancer and 184 healthy volunteers were retrospectively analysed. The MRR and NRR were found to be higher in patients with lung cancer compared with those in healthy controls, while the LRR and LA were lower. The receiver operating characteristic curve analysis revealed that of the four markers, the MRR and LA yielded a higher area under the curve (AUC) (MRR: AUC, 0.810; 95% CI, 0.768-0.847; and LA: AUC, 0.721; 95% CI, 0.674-0.764). The combination of MRR, LA, carcinoembryonic antigen (CEA) and cytokeratin 19 fragment antigen 21-1 (CYFRA21-1) achieved the highest diagnostic value when compared with other single or combined markers (AUC, 0.882; 95% CI, 0.846-0.912; sensitivity, 81.9%; specificity, 81.0%). As the disease progressed, the MRR tended to increase, while LA exhibited a decreasing trend. Binary logistic regression analysis revealed an increase in the MRR, as well as in CEA and CYFRA21-1 concentrations, and a decrease in the LA, which could all be possible risk factors for lung cancer. Differences in the MRR and LA between patients with early stage (IA-IIIA) lung cancer and healthy controls were observed. Further analysis revealed that the MRR also exhibited the potential to detect early stage (IA-IIIA) lung cancer in the model. The present findings demonstrated that the MRR and LA may be used as auxiliary biomarkers for the diagnosis of lung cancer and could partly indicate disease progression.

Study on the inhibitory mechanism of dehydrogenated antioxidants on coal spontaneous combustion.

In order to comprehensively and systematically analyze the reasons why antioxidant inhibitors can scavenge free radicals in coal and inhibit coal spontaneous combustion, this paper studies the effects of VC, TBHQ, EGCG and BHT on coal spontaneous combustion by means of coal spontaneous combustion characteristics experiments and quantum chemical simulation methods. The low-temperature oxidation characteristics of coal were studied through temperature-programmed experiments. The results showed that the CO emission of coal samples with antioxidants was significantly lower than that of raw coal. At 170 °C, the maximum decrease was 37.74%. Fourier infrared test showed that compared with the coal samples without antioxidant treatment, the adsorption strength of hydroxyl structure and oxygen-containing functional groups of the treated coal samples was significantly reduced. The area percentages of hydroxyl and methylene changed significantly, decreased by 7.14% and 6.46%, respectively. Subsequently, molecular models of four antioxidants were constructed using quantum chemical theory, and their Mulliken charges, BDE values ​and frontier orbitals were calculated according to density functional theory (DFT), and the active sites and inhibition mechanisms of antioxidants were discussed. The results showed that H9 of VC, H33 of EGCG, H1 of TBHQ and H40 of BHT all had strong ability to scavenge oxygen-containing free radicals, and their order of strength was TBHQ > BHT > EGCG > VC. Antioxidant inhibitors mainly reduce the number of active free radicals by removing the peroxide groups in the initial stage of the coal oxygen reaction, and remove the hydroxyl groups to prevent the further spontaneous combustion of coal and inhibit the low temperature oxidation process of coal.

VRK1 Is a Synthetic-Lethal Target in VRK2-Deficient Glioblastoma.

Synthetic lethality is a genetic interaction that results in cell death when two genetic deficiencies co-occur but not when either deficiency occurs alone, which can be co-opted for cancer therapeutics. Pairs of paralog genes are among the most straightforward potential synthetic-lethal interactions by virtue of their redundant functions. Here, we demonstrate a paralog-based synthetic lethality by targeting vaccinia-related kinase 1 (VRK1) in glioblastoma (GBM) deficient of VRK2, which is silenced by promoter methylation in approximately two thirds of GBM. Genetic knockdown of VRK1 in VRK2-null or VRK2-methylated cells resulted in decreased activity of the downstream substrate barrier to autointegration factor (BAF), a regulator of post-mitotic nuclear envelope formation. Reduced BAF activity following VRK1 knockdown caused nuclear lobulation, blebbing, and micronucleation, which subsequently resulted in G2-M arrest and DNA damage. The VRK1-VRK2 synthetic-lethal interaction was dependent on VRK1 kinase activity and was rescued by ectopic expression of VRK2. In VRK2-methylated GBM cell line-derived xenograft and patient-derived xenograft models, knockdown of VRK1 led to robust tumor growth inhibition. These results indicate that inhibiting VRK1 kinase activity could be a viable therapeutic strategy in VRK2-methylated GBM. SIGNIFICANCE: A paralog synthetic-lethal interaction between VRK1 and VRK2 sensitizes VRK2-methylated glioblastoma to perturbation of VRK1 kinase activity, supporting VRK1 as a drug discovery target in this disease.

Design and synthesis of stable four-coordinated benzotriazole-borane with tunable fluorescence emission.

A new class of stable four-coordinated benzotriazole-borane compounds was developed via gold-catalyzed alkyne hydroboration. The application of polymeric (BH2CN) n reagent gave the formation of cyano-amine-boranes (CAB) complexes with less basic N-heterocyclic amines and anilines. Various new CABs were investigated in catalytic hydroboration to synthesize N-B cycles. The 1,2,3-benzotriazoles were identified as the only feasible N-source, giving the four coordinated borane N-B cycles (BTAB) in excellent yields (up to 90%) with good functional group tolerability. This new class of polycyclic N-B compounds showed excellent stability toward acid, base, high temperature, and photo-irradiation. The facile synthesis, excellent stability, strong and tunable fluorescence emission make BTAB interesting new fluorescent probes for future chemical and biological applications.

Tongalides, Halogenated Butenolides from an Antarctic Delisea sp. Rhodophyte.

Six new halogenated butenolides, tongalides A-C (1-3) and their acetylated congeners (4-6), were isolated from an extract of the Antarctic rhodophyte Delisea sp. that displayed significant antibiotic activity. The structures of the compounds were determined by analysis of data acquired by spectroscopic and spectrometric techniques including NMR, HRESIMS, optical rotation, and X-ray diffraction studies. The newly isolated compounds were assayed for antibacterial activity, but exhibited no growth inhibition of ESKAPE pathogens. The extract bioactivity was attributed to the previously reported Z-acetoxyfimbrolide A also isolated from the extract, providing further evidence that the exocyclic double bond is essential to the antibacterial activity of the structurally related fimbrolide class of metabolite.

Metallo-Supramolecular Octahedral Cages with Three Types of Chirality towards Spontaneous Resolution.

Chirality is one of the most important intrinsic properties of (supra)molecules. In this study, we obtained enantiomeric metallo-supramolecular octahedra without using any chiral sources. Such cages were self-assembled by prochiral trispyridine ligand L based on a C3h truxene core and CuII salts. Crystallization of the cages with BF4 - as counterions afforded racemate crystals; while crystallizations of cages with ClO4 - and OTf- as counterions resulted in conglomerates with spontaneous resolution. Three types of chirality were observed in each cage, including planar chirality of the truxene core, axial chirality from the pyridyl and truxene moieties, and propeller chirality of the pyridyl-CuII coordination sites. The cages reported here are among the largest discrete synthetic metallo-supramolecules ever reported with chiral self-sorting behavior. Remarkably, the chiral cages exhibited very slow racemization even at low concentrations, suggesting their high stability in solution.

Propensity or diversity? Investigating how mind wandering influences the incubation effect of creativity.

Mind wandering has been argued to be beneficial for breaking through mental impasses, which leads to better creative performance upon a second attempt (i.e., the incubation effect). However, the evidence is inconsistent. Different from the propensity for mind wandering that has been the focus of past studies, in this study we further examined the role of diversity (i.e., non-repetitiveness of mind wandering respective to its content) and types of mind wandering along the dimensions of intentionality and awareness during incubation when engaging in a 0-back task (a mind wandering-prone condition) and a focused-breathing practice (a mindfulness-induced condition). We proposed that diversity rather than the propensity for mind wandering was crucial for post-incubation divergent creativity and that mindfulness induction would be a more effective way to elicit the incubation effect because it should result in fewer but more diverse mind-wandering incidents than engaging in a mind wandering-prone task. We conducted an experiment with a between-participant variable (incubation tasks: mind wandering-prone, mindfulness-induced, and no incubation). As predicted, the mindfulness-induced group (N = 30) outperformed the control group (N = 31) on flexibility for the unusual uses task measuring divergent thinking after incubation, but the mind wandering-prone group (N = 29) did not outperform the control group. In addition, the diversity of mind wandering and the tendency toward intentional mind wandering predicted the magnitude of incubation effects on flexibility and originality, respectively. Theoretical and practical implications are discussed.

Conformational Control of a Metallo-Supramolecular Cage via the Dissymmetrical Modulation of Ligands.

In nature as well as life systems, the presence of asymmetrical and dissymmetrical structures with specific functions is extremely common. However, the construction of metallo-supramolecular assemblies based on dissymmetrical ligands still remains a considerable challenge for avoiding the generation of unexpected isomers with similar thermodynamic stabilities, especially for three-dimensional supramolecular structures. In this study, a strategy for the conformational control of metallo-supramolecular cages via the enhancement of ligand dissymmetry was proposed. Four dissymmetrical ditopic ligands were designed and synthesized. By increasing the dissymmetry of length or angle, conformations of assemblies were precisely controlled to form discrete cis-Pdn L2n molecular cages.

Functional Porphyrinic Metal-Organic Framework as a New Class of Heterogeneous Halogen-Bond-Donor Catalyst.

Biomimetic metal-organic frameworks have attracted great attention as they can be used as bio-inspired models, allowing us to gain important insights into how large biological molecules function as catalysts. In this work, we report the synthesis and utilization of such a metal-metalloporphyrin framework (MMPF) that is constructed from a custom-designed ligand as an efficient halogen bond donor catalyst for Diels-Alder reactions under ambient conditions. The implementation of fabricated halogen bonding capsule as binding pocket with high-density C-Br bonds enabled the use of halogen bonding to facilitate organic transformations in their three-dimensional cavities. Through combined experimental and computational studies, we showed that the substrate molecules diffuse through the pores of the MMPF, establishing a host-guest system via the C-Br⋅⋅⋅π interaction. The formation of halogen bonds is a plausible explanation for the observed boosted catalytic efficiency in Diels-Alder reactions. Moreover, the unique capability of MMPF highlights new opportunities in using artificial non-covalent binding pockets as highly tunable and selective catalytic materials.

Anion mediated, tunable isoguanosine self-assemblies: decoding the conformation influence and solvent effects.

Systematic investigations were performed with various substituted groups at C8 purine and ribose. A series of isoG analogs, C8-phenyl substituted isoG were synthesized and applied for Cs+ coordination. The structural proximity between purine and ribose limited pentaplex formation for C8-phenyl substituted isoG derivatives. Based on this observation, deoxy isoG derivative with modification on ribose (tert-butyldimethylsilyl ether) was applied to assemble with the Cs+ cation. Critical solvent (CDCl3 and CD3CN) and anion (BPh4 -, BARF-, and PF6 -) effects were revealed, leading to the controllable formation of various stable isoG pentaplexes, including singly charged decamer, doubly charged decamer, and 15-mer, etc. Finally, the X-ray crystal structure of [isoG20Cs3]3+(BARF-)3 was successfully obtained, which is the first example of multiple-layer deoxy isoG binding with the Cs+ cation, providing solid evidence of this new isoG ionophore beyond two-layer sandwich self-assembly.

Construction of Stable Helical Metal-Organic Frameworks with a Conformationally Rigid "Concave Ligand".

A helical metal-organic framework was prepared by using a conformationally rigid tetratopic benzoic acid ligand with binding units pointing toward each other (concave ligand). To avoid the obvious intramolecular interactions between binding units, matching spacing groups were applied to introduce atropic repulsion, thereby allowing the formation of extended frameworks for the first time. With this new ligand design, a helical-shaped MOF with significantly improved air and moisture stability was successfully prepared, thus providing a new strategy for ligand design toward porous material constructions.

Highly Stable Single Crystals of Three-Dimensional Porous Oligomer Frameworks Synthesized under Kinetic Conditions.

Various robust, crystalline, and porous organic frameworks based on in situ-formed imine-linked oligomers were investigated. These oligomers self-assembled through collaborative intermolecular hydrogen bonding interactions via liquid-liquid interfacial reactions. The soluble oligomers were kinetic products with multiple unreacted aldehyde groups that acted as hydrogen bond donors and acceptors and directed the assembly of the resulting oligomers into 3D frameworks. The sequential formation of robust covalent linkages and highly reversible hydrogen bonds enforced long-range symmetry and facilitated the production of large single crystals, with structures that were unambiguously determined by single-crystal X-ray diffraction. The unique hierarchical arrangements increased the steric hindrance of the imine bond, which prevented attacks from water molecules, greatly improving the stability. The multiple binding sites in the frameworks enabled rapid sequestration of micropollutant in water.