Stereocontrolled Synthesis of the Fully Glycosylated Monomeric Unit of Lomaiviticin A.

We describe a stereocontrolled synthesis of , the fully glycosylated monomeric unit of the dimeric cytotoxic bacterial metabolite (-)-lomaiviticin A (). A novel strategy involving convergent, site- and stereoselective coupling of the β,γ-unsaturated ketone and the naphthyl bromide (92%, 15:1 diastereomeric ratio (dr)), followed by radical-based annulation and silyl ether cleavage, provided the tetracycle (57% overall), which contains the carbon skeleton of the aglycon of . The β-linked 2,4,6-trideoxy-4-aminoglycoside l-pyrrolosamine was installed in 73% yield and with 15:1 β:α selectivity using a modified Koenigs-Knorr glycosylation.

Development of an Enantioselective Synthesis of (-)-Euonyminol.

We detail the development of the first enantioselective synthetic route to euonyminol (), the most heavily oxidized member of the dihydro-β-agarofuran sesquiterpenes and the nucleus of the macrocyclic alkaloids known as the cathedulins. Key steps in the synthetic sequence include a novel, formal oxyalkylation reaction of an allylic alcohol by [3 + 2] cycloaddition; a tandem lactonization-epoxide opening reaction to form the -C2-C3 vicinal diol residue; and a late-stage diastereoselective trimethylaluminum-mediated α-ketol rearrangement. We report an improved synthesis of the advanced unsaturated ketone intermediate by means of a 6--dig radical cyclization of the enyne .

Enhanced nitrogen and phosphorus removal by natural pyrite-based constructed wetland with intermittent aeration.

Four subsurface flow constructed wetlands (SFCWs) filled with different substrates including ceramsite, ceramsite+pyrite, ceramsite+ferrous sulfide, and ceramsite+pyrite+ferrous sulfide (labeled as SFCW-S1, SFCW-S2, SFCW-S3, and SFCW-S4) were constructed, and the removal of nitrogen and phosphorus by these SFCWs coupled with intermittent aeration in the front section was discussed. The key findings from different substrate analyses, including nitrification and denitrification rate, enzyme activity, microbial community structure, and the X-ray diffraction, revealed the nitrogen and phosphorus removal mechanism. The results showed that the nitrogen and phosphorus removal efficiency for SFCW-S1 always remained the lowest, and the phosphorus removal efficiency for SFCW-S4 was recorded as the highest one.

Synthesis and Activity Investigation of Novel 1-Purin-6(9)-one and 3-Imidazo[4,5-][1,2,3]triazin-4(7)-one Derivatives.

Novel 1-purin-6(9)-one () and 3-imidazo[4,5-][1,2,3]trazin-4(7)-one () derivatives were designed, synthesized, and characterized by H NMR, C NMR and high-resolution mass spectrometry spectra. Their herbicidal activity bioassay showed that compound exhibited relatively good activity with 70.4% inhibition rate against in postemergence treatments at 1500 g/ha.

Scalable Total Synthesis of (-)-Vinigrol.

Vinigrol is a structurally and stereochemically complex natural product that displays various potent pharmacological activities, including the capability to modulate TNF-α. A new and efficient synthetic route toward this natural product has been developed to complete the asymmetric synthesis of (-)-vinigrol and provide over 600 mg of material, manifesting the power of macrocyclic stereocontrol and transannular Diels-Alder reaction.

Identification of the binding between three fluoronucleoside analogues and fat mass and obesity-associated protein by isothermal titration calorimetry and spectroscopic techniques.

In this work, the interactions between fat mass and obesity-associated (FTO) protein and three fluoronucleoside analogues (three-member-ring compound (1a), five-member-ring compound (1b) and six-member-ring compound (1c)) have been investigated by fluorescence, ultraviolet-visible absorption spectroscopy, isothermal titration calorimetric (ITC) and molecular modeling. Analysis of fluorescence data showed that the binding between three analogues and FTO occurred via a static quenching mechanism. Both ITC and fluorescence results indicated that 1b is the strongest quencher.

Study on the interaction between cannabinol and DNA using acridine orange as a fluorescence probe.

The interaction between cannabinol (CBN) and herring-sperm deoxyribonucleic acid was investigated by using acridine orange as a fluorescence probe in this work. UV-Vis spectroscopy, fluorescence spectroscopy, and DNA melting techniques were used. The fluorescence of DNA acridine orange was quenched by CBN.

Interaction of two flavonols with fat mass and obesity-associated protein investigated by fluorescence quenching and molecular docking.

The binding of two flavonols with fat mass and obesity-associated protein (FTO) was studied using fluorescence spectroscopy, Stern-Volmer kinetics, UV-Vis absorption, and molecular docking. The quenching of FTO fluorescence was determined to be static with binding constants on the order of 10 M. The interaction was studied over three temperatures, and the binding was found to be exothermic with a positive change in entropy.

Study of the Binding between Camptothecin Analogs and FTO by Spectroscopy and Molecular Docking.

In this work, the interaction between camptothecin (CPT) analogs and fat mass and obesity associated (FTO) was investigated using spectroscopy and molecular docking. From the experimental results, it was found that the CPT analogs caused the fluorescence quenching of FTO through a static quenching procedure. The binding constants and thermodynamic parameters at three different temperatures, the number of binding sites were obtained, which suggested that the hydrophobic interaction and electrostatic force played major role in the reaction between CPT analogs and FTO.

Comparative study of the binding of 3 flavonoids to the fat mass and obesity-associated protein by spectroscopy and molecular modeling.

This study aims to investigate the interaction between 3 flavonoids (quercetin, apigenin, and naringenin) and fat mass and obesity-associated protein by fluorescence, ultraviolet-visible absorption spectroscopy, and molecular modeling. Results indicate that the intrinsic fluorescence of fat mass and obesity-associated protein can be quenched by the 3 flavonoids through a static quenching procedure. Thermodynamic analysis and molecular modeling results suggest that hydrophobic interaction and hydrogen bond forces play the major roles in the binding process.

Investigation of the Interaction between 1,3-Diazaheterocyclic Compounds and the Fat Mass and Obesity-Associated Protein by Fluorescence Spectroscopy and Molecular Modeling.

In this paper, The binding of twelve 1,3-diazaheterocyclic compounds (1a-1 l) to the fat mass and obesity-associated (FTO) protein was investigated by fluorescence, UV-vis absorption spectroscopy and molecular modeling. Results indicated that the intrinsic fluorescence of FTO is quenched by the nine compounds (1a-1i) with a static quenching procedure. No interaction was observed between FTO protein and compounds (1j-1 l).