α-Acyloxylation of Ketones/Cyclic Ethers Mediated by Hypervalent Iodine(III) Reagents as Oxidants and Nucleophilic Sources.

This study describes a catalyst-free α-acyloxylation of ketones and a KBr-mediated α-acyloxylation of cyclic ethers. These conversions are effectively mediated by hypervalent iodine(III) reagents serving dual roles as the oxidant and nucleophilic source. Consequently, esters are produced directly in moderate to excellent yields. The proposed method features good functional group compatibility, a broad substrate scope, and high synthetic efficiency and is remarkably environmentally friendly.

Metal-free iodination of arylaldehydes for total synthesis of aristogins A-F and hernandial.

Iodine is one of the most effective sources for iodination of aromatic compounds; however, its electrophilicity is insufficient for direct iodination. The selection of appropriate environmentally friendly and cost-effective oxidants in combination with iodine for the iodination of aromatic rings, along with its application in the synthesis of natural products, holds significant importance. A highly efficient method utilizing I(III) as the initiator has been successfully developed for monoiodination of arylaldehydes. The method demonstrates good compatibility with a wide range of (hetero)aromatic aldehydes, resulting in moderate to excellent yields, without the need for any toxic, volatile or explosive reagents. The synthesis of seven natural products, namely aristogins A-F and hernandial, was achieved through this iodination followed by Ullmann-type coupling.

Design, synthesis and anticancer activity of naphthoquinone derivatives.

Basis on molecular docking and pharmacophore analysis of naphthoquinone moiety, a total of 23 compounds were designed and synthesised. With the help of reverse targets searching, anti-cancer activity was preliminarily evaluated, most of them are effective against some tumour cells, especially compound 12: 1-(5,8-dihydroxy-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-4-methylpent-3-en-1-yl-4-oxo-4-((4-phenoxyphenyl)amino) butanoate whose IC50 against SGC-7901 was 4.1 ± 2.6 µM. Meanwhile the anticancer mechanism of compound 12 had been investigated by AnnexinV/PI staining, immunofluorescence, Western blot assay and molecular docking. The results indicated that this compound might induce cell apoptosis and cell autophagy through regulating the PI3K signal pathway.

Iodine(III) promotes cross-dehydrogenative coupling of N-hydroxyphthalimide and unactivated C(sp3)-H bonds.

Cross-dehydrogenative coupling reactions provide a method to construct new chemical bonds by direct C-H activation without any pre-functionalization. Compared to functionalization of a C-H bond α- to ether oxygen, α- to carbonyl, or at a benzylic position, functionalization of unactivated hydrocarbons is difficult and often requires high temperatures, a transition-metal catalyst, or a superstoichiometric quantity of volatile, toxic, and explosive tert-butylhydroperoxide. Here, a cross-dehydrogenative C-O coupling reaction of N-hydroxyphthalimide with unactivated alkanes, nitriles, ethers, and thioethers has been realized by using iodobenzene diacetate as the radical initiator. The current protocol enables efficient functionalization of unactivated hydrocarbons and nitriles through inert C(sp3)-H bond activation under mild reaction conditions. O-substituted NHPI derivatives are generated in good yields under metal-free conditions.

A novel lignin degradation bacteria-Bacillus amyloliquefaciens SL-7 used to degrade straw lignin efficiently.

Using tobacco straw (Ts) and lignin as the sole carbon source, a strain was isolated from Ts and identified as Bacillus amyloliquefaciens SL-7 by 16S rDNA gene-sequencing technology.7-day incubation of Bacillus amyloliquefaciens SL-7 can reduce the chemical oxygen demand (COD) by 69.35% in lignin mineral salt medium. The activity of Manganese peroxidase (MnP) reached maximum level 258.57 U L-1, and Lignin peroxidase (Lip) was 422.68 U L-1 at 4th day. The highest Laccase (Lac) activity (55.95 U L-1) was observed at 3th day. After straw-liquid fermentation degradation of 15 days, the bacterial could degrade 28.55% lignin of the straw which was close to that of fungi. Compared with the control group and effective microorganisms (EM) group, the lignin degradation rate in Bacillus amyloliquefaciens SL-7 group increased by 22.26% and 11.70% at 41-day compost fermentation of tobacco straw. These show the strain has strong lignin degradation performance.

Yb-Doped BaCeO3 and Its Composite Electrolyte for Intermediate-Temperature Solid Oxide Fuel Cells.

BaCe0.9Yb0.1O3-α was prepared via the sol-gel method using zirconium nitrate, ytterbium trioxide, cerium nitrate and barium acetate as raw materials. Subsequently, it reacted with the binary NaCl~KCl salt to obtain BaCe0.9Yb0.1O3-α-NaCl~KCl composite electrolyte. The structure, morphology, conductivity and fuel cell performance of the obtained samples were investigated. Scanning electron microscope (SEM) images showed that BaCe0.9Yb0.1O3-α and NaCl~KCl combined with each other to form a homogeneous 3-D reticulated structure. The highest power density and conductivity of BaCe0.9Yb0.1O3-α-NaCl~KCl was 393 mW·cm-2 and 3.0 × 10-1 S·cm-1 at 700 °C, respectively.

Study on the interaction and antioxidant activity of theophylline and theobromine with SOD by spectra and calculation.

Theophylline (TP) and theobromine (TB) are the methyl derivatives of xanthine. The antioxidation of TP and TB as well as the effect of the antioxidation and activity of copper­zinc superoxide dismutase (SOD) with TP and TB were investigated. The contents of MDA in cells showed that both TP (14.49 µmol/g) and TB (14.25 µmol/g) are active in oxidation resistance and closed to the antioxidant effect of SOD (13.77 µmol/g). With the formation of TP-SOD and TB-SOD, the antioxidant ability can be superimposed. The interactions between TP/TB and SOD were studied by ultraviolet spectrum, fluorescence spectrum and molecular docking. The results showed that the complex of TP/TB and SOD with 1:1 component was stabilized by hydrogen bonding and van der Waals forces. The analysis also indicated that the microenvironment and structure of SOD were changed. All of the results indicate that the complex formation of TP-SOD and TB-SOD can maintain their respective antioxidant effects without changes in the activity of SOD.

Preparation, Characterization and Intermediate-Temperature Electrochemical Properties of Er3+-Doped Barium Cerate-Sulphate Composite Electrolyte.

In this study, BaCe0.9Er0.1O3-α was synthesized by a microemulsion method. Then, a BaCe0.9Er0.1O3-α-K2SO4-BaSO4 composite electrolyte was obtained by compounding it with a K2SO4-Li2SO4 solid solution. BaCe0.9Er0.1O3-α and BaCe0.9Er0.1O3-α-K2SO4-BaSO4 were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectrometry. AC impedance spectroscopy was measured in a nitrogen atmosphere at 400-700 °C. The logσ~log (pO2) curves and fuel cell performances of BaCe0.9Er0.1O3-α and BaCe0.9Er0.1O3-α-K2SO4-BaSO4 were tested at 700 °C. The maximum output power density of BaCe0.9Er0.1O3-α-K2SO4-BaSO4 was 115.9 mW·cm-2 at 700 °C, which is ten times higher than that of BaCe0.9Er0.1O3-α.

Binding Characteristics and Superimposed Antioxidant Properties of Caffeine Combined with Superoxide Dismutase.

The binding characteristics and superimposed antioxidant properties of caffeine combined with copper/zinc superoxide dismutase (SOD) were studied. The superimposed antioxidant activity of caffeine with SOD was investigated by detecting the concentration of malondialdehyde (MDA) present in cells, which was induced by hyperthermia and heavy metal exposure. The interactions between the SOD enzyme and caffeine were researched by ultraviolet spectrum, fluorescence spectrum, and molecular computation. The relative amounts of MDA contents of caffeine (0.1 mmol/L), SOD (0.1 mg/L), and caffeine (0.1 mmol/L) and SOD (0.1 mg/L) to water in cells were 0.70, 0.72, and 0.54, respectively, indicating that the antioxidant properties of caffeine combined with SOD may be superimposed. The fluorescence spectroscopy and molecular computation results show that the mixture of caffeine and SOD can result in the formation of a 1:1 complex through hydrogen bond and van der Waals forces spontaneously. The binding constant (K a) of caffeine with SOD at five different temperatures are 4.41 × 104, 3.30 × 104, 2.29 × 104, 1.71 × 104, and 1.17 × 104 L/mol. The changes of Gibbs-free energy (ΔG) are -26.50, -26.21, -25.71, -25.12, and -24.29 KJ/mol and the ΔG of molecular docking calculation is -26.95 KJ/mol. The experimental results are in accordance with the results of theoretical calculations. The combination of caffeine with SOD can change the conformation and microenvironment of SOD but does not change the activity of SOD. In addition, the combination can superimpose the antioxidant activity of caffeine and SOD.

The homeostasis-maintaining metabolites from bacterial stress response to bacteriophage infection suppress tumor metastasis.

The antiviral metabolites from bacterial stress response to bacteriophage infection can maintain homeostasis of host cells, while metabolism disorder is a remarkable characteristic of tumorigenesis. In the aspect of metabolic homeostasis, therefore, the antiviral homeostasis-maintaining metabolites of bacteria may possess anti-tumor activity. However, this issue has not been addressed. Here we show that the homeostasis-challenged maintaining metabolites from deep-sea bacteriophage-challenged thermophile can suppress tumor metastasis. The results indicated that the metabolic profiles of the bacteriophage GVE2-infected and virus-free thermophile Geobacillus sp. E263 from a deep-sea hydrothermal vent were remarkably different. Thirteen metabolites were significantly elevated and two metabolites were downregulated in thermophile stress response to GVE2 infection. As an example, the upregulated L-norleucine was characterized. The data showed that L-norleucine had antiviral activity in thermophile. Furthermore, the in vitro and in vivo assays revealed that L-norleucine, as well as its derivative, significantly suppressed metastasis of gastric and breast cancer cells. L-norleucine interacted with hnRNPA2/B1 protein to inhibit the expressions of Twist1 and Snail, two inhibitors of E-cadherin, and promote the E-cadherin expression, leading to the inhibition of tumor metastasis. Therefore, our study presented that antiviral homeostasis-maintaining metabolites of microbes might be a promising source for anti-tumor drugs.

Direct access to tetrahydro[1,2]diazepinones from α,ß-epoxy-N-aziridinylimines via anionic rearrangement.

A novel one-step synthetic approach to tetrahydro[1,2]diazepinones via base-promoted rearrangement of α,ß-epoxy-N-aziridinylimines, derived from α,ß-epoxyketones and N-aminoaziridines, has been developed.