Anti-inflammatory polyketides from the mangrove-derived fungus Ascomycota sp. SK2YWS-L

A pair of novel 2,3-diaryl indone derivatives (+)- and (?)-ascomindone D [(+)-1 and (?)-1, respectively], as well as two new prenylated polyketides ascomfurans C (2) and ascomarugosin A (3) were obtained from the culture of a mangrove endophytic fungus Ascomycota sp. SK2YWS-L together with three known compounds (4–6). The enantiomers (+)-1 and (?)-1 were purified through chiral HPLC separation, which represented the first example of resolving 2,3-diaryl indone atropisomers in natural products. The structures of the new compounds were determined on the basis of interpretation of spectroscopic data including X-ray diffractions and the absolute configurations of (+)-1 and (?)-1 were elucidated by ECD calculations. The biosynthesis pathway was proposed. In the anti-inflammatory assay, (+)-1 and (?)-1 exhibited potential anti-inflammatory effects by inhibiting against the production of nitric oxide (NO) in lipopolysaccharide (LPS)-induced RAW 246.7 mouse macrophages with the IC₅₀ values of 17.0 and 17.1 μM, respectively.     

Two‐dimensional hydrogen‐bonded networks in two novel glycoluril derivatives

Two new glycoluril derivatives, namely diethyl 6‐ethyl‐1,4‐dioxo‐1,2,2a,3,4,6,7,7b‐octahydro‐5H‐2,3,4a,6,7a‐pentaazacyclopenta[cd]indene‐2a,7b‐dicarboxylate, C₁₄H₂₁N₅O₆, (I), and 6‐ethyl‐2a,7b‐diphenyl‐1,2,2a,3,4,6,7,7b‐octahydro‐5H‐2,3,4a,6,7a‐pentaazacyclopenta[cd]indene‐1,4‐dione, C₂₀H₂₁N₅O₂, (II), both bearing two free syn‐urea NH groups and two ureidyl C=O groups, assemble the same one‐dimensional chains in the solid state running parallel to the [010] direction via N—H...O hydrogen bonds. Furthermore, the chains of (I) are linked together into two‐dimensional networks via C—H...O hydrogen bonds.     

Tetrameric molecular bowl assembled from glycoluril building blocks

Glycoluril derivative--whose bulky Ph-C[triple bond]C- substituents prevent formation of H-bonded tapes--undergoes solvent dependent assembly in the crystal; a tetrameric molecular bowl is formed by R(24) H-bonding interactions from CH(2)Cl(2) whereas DMF results in H-bond dimerization followed by oligomerization via C-H...pi interactions.     

Syntheses,Crystal Structures and Luminescent Properties of Three Inorganic‐Organic Hybrid Frameworks Constructed from 4,5‐Imidazoledicarboxylate

Three inorganic‐organic hybrid frameworks [Mn(HIMDC)(4,4′‐bipyo)_0.5(H₂O)]_n (1) , [Cd(H₂IMDC)₂(2,2′‐bipyo)] (2) and [Ca(HIMDC)(H₂O)₂·H₂O]_n (3) (H₃IMDC = 4,5‐imidazoledicarboxylate; 4,4′‐bipyo = 4,4′‐bipyridine‐N,N′‐dioxide; 2,2′‐bipyo= 2,2′‐bipyridine‐N,N′‐dioxide) have been hydrothermally synthesized and characterized by the elemental analyses, IR spectra, TG analysis and the single crystal diffraction. Both compounds 1 and 3 exhibit 2D layers while 2 is a monomer. It is noteworthy that compound 2 exhibits strong fluorescent emission in the solid state at room temperature.     

Preparation and in vitro degradation of porous three-dimensional silk fibroin/chitosan scaffold

Degradation behaviors of porous scaffolds play an important role in the engineering process of a new tissue. In this study, three-dimensional porous silk fibroin/chitosan (SFCS) scaffolds were successfully prepared by freeze-drying method. In vitro degradation behaviors of SFCS scaffolds have been systematically investigated up to 8 weeks in phosphate buffer saline (PBS) solution at 37 °C. The following properties of the scaffolds were measured as a function of degradation time: pore morphology, structure, weight loss, and wet/dry weight value. The pH value of the PBS solution during degradation was also detected. SFCS scaffolds maintained its porous structure till 6 weeks of degradation. During the first 2 weeks, the pH value fluctuated in a narrow range from 6.53 to 6.93. SFCS scaffolds degraded much more quickly during the first 2 weeks, and the weight loss reached 19.28 wt% after 8 weeks of degradation. The degradation process affects little SFCS scaffolds' swelling properties.     

2,5-二苯腙基-1,3,4-噻二唑类化合物的合成及抗腐蚀性能研究

以2,5-二巯基-1,3,4-噻二唑为原料, 与水合肼反应制得2,5-二肼基-1,3,4-噻二唑, 再将其与取代苯甲醛缩合, 得到了6种新的2,5-二苯腙基-1,3,4-噻二唑类化合物, 其结构经元素分析、红外、¹H NMR及质谱等方法所证实. 6种噻二唑衍生物对喷气燃料银片腐蚀有一定的抑制作用.     

Synthesis, crystal structure, and optical properties of a novel rare-earth complex Nd(C2F5COO)3 · Phen

A novel neodymium pentafluoropropionate binuclear complex, Nd(C₂F₅COO)₃ · Phen (Phen: 1,10-phenanthroline), was synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, FT-IR spectra, UV–Vis–NIR absorption, and PL spectra. Single-crystal data show that the complex bears centrosymmetric dinuclear structure with a planar ligand configuration. Four carboxylato groups act as η²-chelate-μ²-carboxylato-k¹O:k¹O′-bridge-ligands, the other two occupy the terminal position as monodentate ligands. At the same time, the C–O distances appear averaged which indicate the three atoms of carboxylato forming electron-conjugate system. Hydrogen bond and π–π-stacking link the binuclear to two-dimensional sheet. Optical spectra exhibit the complex possesses typical Nd(III) ion absorption and photoluminescence emission.     

Direct NMR evidence for Ca2+ ion binding to G-quartets

We report the first 1H and 43Ca NMR characterization of Ca2+ ion binding to G-quartets.