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This paper describes a catalytic asymmetric Staudinger-aza-Wittig reaction of (o-azidoaryl)malonates, allowing access to chiral quaternary oxindoles through phosphine oxide catalysis. We designed a novel HypPhos oxide catalyst to enable the desymmetrizing Staudinger-aza-Wittig reaction through the PIII/PV═O redox cycle in the presence of a silane reductant and an IrI-based Lewis acid. The reaction occurs under mild conditions, with good functional group tolerance, a wide substrate scope, and excellent enantioselectivity. Density functional theory revealed that the enantioselectivity in the desymmetrizing reaction arose from the cooperative effects of the IrI species and the HypPhos catalyst. The utility of this methodology is demonstrated by the (formal) syntheses of seven alkaloid targets: (-)-gliocladin C, (-)-coerulescine, (-)-horsfiline, (+)-deoxyeseroline, (+)-esermethole, (+)-physostigmine, and (+)-physovenine.

This paper presents a methodology for actively discovering knowledge in transport hotline databases by analyzing complaints reported by citizens, aiming to assist transportation management departments in planning actions to investigate and improve service quality. The proposed model uses text mining techniques and applies latent Dirichlet allocation (LDA) to identify topics that are related to transportation services. Consequently, we actively analyzed over 230,000 phone calls occurring in a certain province between 1st January and 31st December 2021. Specifically, we actively analyzed nearly 22,000 phone calls about the taxi industry within a selected city, and identified six topics, including lost and found (27.1%), car blocking (20.6%), attitude and behavior (17.1%), online car-hailing (12.8%), illegal operations (11.2%), and fare issues (11.2%). By actively referring to past and ongoing best practices, we actively recommend several policy implications. The proposed method thus actively transforms the service center record into a customer feedback-based assessment system to intently monitor drivers' professionalism while efficiently addressing customers' complaints and concerns., Author(s): Ruo-yu Wu [1]; Chun-fu Shao (corresponding author) [1]; Cheng-xiang Zhuge [2]; Xin-yi Wang [3]; Xu-yang Yin [3] 1. Introduction China has experienced rapid urbanization, in recent decades, resulting in [...]

Objective To explore the effect of prednisone acetate on renal function, renal inflammatory response and AMP-activated protein kinase (AMPK)/silent information regulator 1 (SIRT1) signaling pathway in diabetic nephropathy (DN) rats. Methods Twelve rats were randomly selected as the control group, and the remaining rats were given high-sugar and high-fat diet supplemented with intraperitoneal injection of streptozotocin (STZ) to construct a DN rat model. The successful model rats were randomly divided into model group, prednisone acetate low (6.25 mg/kg), high (12.5 mg/kg) dose groups, prednisone acetate + CC group (prednisone acetate 12.5 mg/kg+AMPK inhibitor compound C 0.2 mg/kg), with 12 animals in each group. Each group was given corresponding treatment, once a day for 4 weeks. The general state of rats was observed, and the fasting blood glucose (FBG), 24-hour urine microalbumin (U-mAlb), blood creatinine (SCr), blood urea nitrogen (BUN), serum interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were detected; the pathological changes of renal tissue were observed with hematoxylin eosin (HE) staining and periodate schiff (PAS) staining; The expression of proteins related to the renal tissue AMPK/SIRT1 signaling pathway was detected with Western blot. Results Prednisone acetate can improve the general state of DN rats, reduce FBG, 24 h U-mAlb, serum SCr, BUN, IL-1β, IL-6 and TNF-α levels, and renal tissue acetylation nuclear factor-κB p65 (ac-NF-κB p65)/NF-κB p65 and monocyte chemotactic protein-1 (MCP-1) protein expression (P＜0.05), increase phosphorylated AMPK(p-AMPK)/AMPK and SIRT1 protein expression (P＜0.05), improve kidney disease; compound C could significantly weaken the protective effect of prednisone acetate on DN rats. Conclusions Prednisone acetate can reduce renal inflammatory response and protect renal function in DN rats. Its mechanism may be related to the activation of AMPK/SIRT1 pathway to inhibit the activation of NF-κB.

In the present era, the fixation of atmospheric CO2 is of significant importance and plays a crucial role in maintaining the balance of carbon and energy flow within ecosystems. Generally, CO2 fixation is carried out by autotrophic organisms; however, the scientific community has paid substantial attention to execute this process in laboratory. In this report, we synthesized two carbonato-bridged trinuclear copper(II) complexes, [Cu3(L1)3(μ3-CO3)](ClO4)3 (1) and [Cu3(L2)3(μ3-CO3)](ClO4)3 (2) via atmospheric fixation of CO2 starting with Cu(ClO4)2·6H2O and easily accessible pyridine/pyrazine-based N4 donor Schiff base ligands L1 and L2, respectively. Under very similar reaction conditions, the ligand framework embedded with the phenolate moiety (HL3) fails to do so because of the reduction of the Lewis acidity of the metal center, inhibiting the formation of a reactive hydroxide bound copper(II) species, which is required for the fixation of atmospheric CO2. X-ray crystal structures display that carbonate-oxygen atoms bridge three copper(II) centers in μ3syn–anti disposition in 1 and 2, whereas [Cu(HL3)(ClO4)] (3) is a mononuclear complex. Interestingly, we also isolated an important intermediate of atmospheric CO2 fixation and structurally characterized it as an anti–anti μ2 carbonato-bridged dinuclear copper(II) complex, [Cu2(L2)2(μ2-CO3)](ClO4)2·MeOH (2-I), providing an in-depth understanding of CO2 fixation in these systems. Variable temperature magnetic susceptibility measurement suggests ferromagnetic interactions between the metal centers in both 1 and 2, and the results have been further supported by DFT calculations. The catalytic efficiency of our synthesized complexes 1–3 was checked by means of catechol oxidase and phenoxazinone synthase-like activities. While complexes 1 and 2 showed oxidase-like activity for aerobic oxidation of o-aminophenol and 3,5-di-tert-butylcatechol, complex 3 was found to be feebly active. ESI mass spectrometry revealed that the oxidation reaction proceeds through the formation of complex–substrate intermediations and was further substantiated by DFT calculations. Moreover, active catalysts 1 and 2 were effectively utilized for the base-free oxidation of benzylic alcohols in the presence of air as a green and sustainable oxidant and catalytic amount of TEMPO in acetonitrile. Various substituted benzylic alcohols smoothly converted to their corresponding aldehydes under very mild conditions and ambient temperature. The present catalytic protocol showcases its environmental sustainability by producing minimal waste. [ABSTRACT FROM AUTHOR]

Specific detection of glycoproteins such as transferrin (TRF) related to neurological diseases, hepatoma and other diseases always plays an important role in the field of disease diagnosis. We designed an antibody-free immunoassay sensing method based on molecularly imprinted polymers (MIPs) formed by the polymerization of multiple functional monomers for the sensitive and selective detection of TRF in human serum. In the sandwich surface-enhanced Raman spectroscopy (SERS) sensor, the TRF-oriented magnetic MIP nanoparticles (Fe3O4@SiO2–MIPs) served as capture units to specifically recognize TRF and 4-mercaptophenylboronic acid-functionalized gold nanorods (MPBA–Au NRs) served as SERS probes to label the targets. In order to achieve stronger interaction between the recognition cavities of the prepared MIPs and the different amino acid fragments that make up TRF, Fe3O4@SiO2–MIPs were obtained through polycondensation reactions between more silylating reagents, enhancing the specific recognition of the entire TRF protein and achieving high IF. This sensing method exhibited a good linear response to TRF within the TRF concentration range of 0.01 ng mL−1 to 1 mg mL−1 (R2 = 0.9974), and the LOD was 0.00407 ng mL−1 (S/N = 3). The good stability, reproducibility and specificity of the resulting MIP based SERS sensor were demonstrated. The determination of TRF in human serum confirmed the feasibility of the method in practical applications. [ABSTRACT FROM AUTHOR]

AbstractGuiding by LC-MS/MS analysis and the Global Natural Products Social (GNPS) Molecular Networking, three undescribed sesquiterpenoids, stedapgens A–C, and two known analogues were discovered in the barks of Daphne genkwa Sieb. et Zucc. The structures were determined by analysis of their spectroscopic data and quantum-chemical calculations. All the isolated novel compounds were tested for their acetylcholinesterase inhibitory activities with IC50 = 0.754 ± 0.059, 0.696 ± 0.026, and 0.337 ± 0.023 μg/ml. Among them, stedapgen A displayed promising inhibitory activities against AChE, and the binding sites were predicted by molecular docking. [ABSTRACT FROM AUTHOR]