Novel and potent Lewis acid catalyst: Br2-catalyzed Friedel–Crafts reactions of naphthols with aldehydes

A discovery that the inexpensive Br₂ can serve as a potent Lewis acid catalyst for bis(2-hydroxy-1-naphthyl)methanes synthesis is presented. Under the catalysis of Br₂ at room temperature, naphthols reacted smoothly with various aldehydes with high efficiency and broad substrate scope. This reaction used to require highly acidic conditions and/or high temperature and/or pressure, and sometimes featured poor yields. Moreover, theoretical calculations suggested that Br₂ is a potent Lewis acid to activate the carbonyl group, yet it was not the primary cause for the remarkable activity of Br₂ in the current communication.     

Chemical composition and biological activities of essential oil from Filifolium sibiricum (L.) Kitam

The essential oil from Filifolium sibiricum (L.) Kitam were extracted using hydrodistillation and GC-MS was used to analyse the essential oil. The main components were espatulenol (8.55%), geranyl acetate (8.03%), caryophyllene oxide (5.47%), calamenene (4.79%), geraniol (4.28%), calamenene (4.53%), geraniol (4.06%), cedrene epoxide (3.23%), myrtenol (3.18%), transgeranylgeranio (3.13%), etc. The essential oil showed intensive inhibitory effects against MCF-7 with IC₅₀ level of 0.78 mg/mL, HepG-2 with IC₅₀ level of 0.44 mg/mL, SKOV-3 with IC₅₀ level of 0.27 mg/mL, BGC-823 with IC₅₀ level of 0.34 mg/mL. In the antibacterial test, the essential oil showed the significant antibacterial activities. The MIC and MBC values were 5.20 and 5.20 mg/mL against Staphylococcus aureus.     

影响TiMnx非计量比合金储氢容量的结构因素

以TiMn_x (x = 1.4, 1.5, 1.6, 1.7)非计量比合金为对象,系统研究了储氢容量与其内在结构之间的相关性。结果表明,所有合金的主相均为C14型Laves相,但其储氢容量却存在显著差异。其中TiMn_1.4合金的储氢量约为0.65% (w,质量分数),吸/放氢平台较倾斜,且存在明显的滞后;而TiMn_1.5合金的可逆储氢量达到1.2% (w),平台较为平坦;但继续增加x,其储氢量反而降低,如x = 1.6合金的储氢量仅为0.30% (w),而x = 1.7合金则几乎不吸氢。进一步结构解析表明,上述储氢容量的迥异主要归因于部分Ti原子占据Mn(2a)位置,且其占位率随x的增加而降低,随之C14相中贮氢四面体间隙体积减小;而引起贮氢四面体间隙体积发生变化的主要因素是Ti―Ti键和Mn(2a)―Mn(2a)键的键长,其中Mn(2a)―Mn(2a)键长的增加对合金储氢容量的提升起关键作用。     

Synthesis and Properties of New Tricephalic Tetrasiloxane Surfactants Containing Carbohydrate and Hydrocarbon Chain

A new family of tricephalic tetrasiloxane surfactants containing carbohydrate and hydrocarbon chain (SiC(n + 1)N-GA, in which n + 1 represents a hydrocarbon chain length of 1, 8, 12, 16), was synthesized using two-step method. Their structures were confirmed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (¹H NMR). Their surface activities and aggregation properties in aqueous solution were investigated by surface tension measurements, transmission electron microscopy, and dynamic light scattering. The results indicated that the critical micelle concentration (CMC) of these surfactants increased and the surface tension (γ_CMC) at the CMC decreased with an increase in the number of hydrocarbon chain, and they can self-assemble into spherical micelles with average diameters in the range from 5 to 200 nm, which are smaller than for single-headed surfactants.     

A new tigliane-type diterpene from Euphorbia dracunculoides Lam

One new tigliane-type diterpene, 4-deoxy-4(β)H-8-hydroperoxyphorbol-12-benzoate-13-isobutyrate (1), together with two known diterpenoids, 3-acetyl-5,8-dibenzoyl-14α-propanoyl-13,17-epoxy-7-myrsinaone diterpene with C9–C10 cyclised to form an additional lactone ring (2), Euphodendriane A (3) have been isolated from the whole plants of Euphorbia dracunculoides Lam. Their structures were elucidated by means of extensive spectroscopic analysis (NMR and HR-ESI-MS) and comparison with data reported in the literature. This is the first isolation of 8-hydroperoxy tigliane diterpene (1) from the genus of Euphorbia. All compounds were evaluated for their antifungal activities.     

Paeonenoides D and E: Two New Nortriterpenoids from Paeonia lactiflora and Their Inhibitory Activities on NO Production

Two new nortriterpenoids, paeonenoides D and E ( 1 and 2 , resp.), together with seven known compounds, were isolated from the roots of Paeonia lactiflora. Their structures were elucidated on the basis of spectroscopic evidence. Compounds 1 – 7 were screened for inhibitory effects against NO production in LPS‐induced RAW246.7 macrophages and for cytotoxic activities against HL‐60, Hep‐G2, and SK‐OV‐3 cell lines. Compounds 1 – 3 and 5 – 7 exhibited inhibitory activities with IC₅₀ values in the range of 9.6–32.2 μM . Triterpenoids with an epoxide ring and a free COOH function, 1 – 3 , showed effectively increased activities compared with other pentacyclic triterpenoids. Compounds 1 – 6 showed significant cytotoxic activities against the Hep‐G2 cell line and modest cytotoxic activities against HL‐60 and SK‐OV‐3 cell lines.     

Energy‐resolved technique for discovery and identification of malonyl‐triterpene saponins in Caulophyllum robustum by UHPLC‐electrospray Fourier transform mass spectrometry

Malonyl‐triterpene saponins (MTSs) attract scientific attentions because of their structural diversities and valuable bioactivities. However, its thermal instability brings a huge amount of challenges for isolation and purification of this class of compounds. To our best knowledge, there has been no report on isolation and analysis of MTSs from genus Caulophyllum. In this study, a strategy combining data acquisition using an energy‐resolved technique and the narrow widow extracted ion chromatograms as data mining method was developed for discovery and identification of MTSs in Caulophyllum robustum hair roots by ultra high liquid chromatography coupled to electrospray ionization Fourier transform mass spectrometry. The method was performed at an independent MS full scan using our bottom‐up energies by in‐source collision induced dissociations with 0, 25, 50 and 100 eV in both positive and negative modes. Precursor ion as well as fragment ion information was simultaneously collected from four energy‐resolved MS spectra in a single run of 18 min. The fragmentation pathways of intact deprotonated, protonated and sodium ions of MTSs were proposed for the structural elucidation of Caulophyllum MTSs. A flowchart involving a stepwise procedure based on key fragments from ESI^?/ESI⁺‐FT‐MS^{(1, 1)} to MS^{(1, 4)} spectra was constructed for the identification of structural elements in the MTSs. As a result, a total of 23 MTSs were discovered and tentatively identified, which had not been reported from Caulophyllum species before. All of these were potentially new compounds. This study provides an excellent example for discovery and identification of MTSs in herb medicines. Copyright © 2016 John Wiley & Sons, Ltd.     

Flexible Hierarchical TiO2/Fe2O3 Composite Membrane with High Separation Efficiency for Surfactant‐Stabilized Oil‐Water Emulsions

Globally, efficient oil‐water separation for surfactant‐stabilized oil‐water emulsions has been in urgent demand. The current options available for separation are neither sustainable nor resistant to fouling. Herein, we introduce a hierarchically nanostructured TiO₂/Fe₂O₃ composite membrane, which is capable of separating surfactant‐stabilized oil‐water emulsions with high separation efficiency. The high oil rejection rate is contributed by the acquisition of an interconnected delicate network and underwater superoleophobic interface. Meanwhile, its self‐cleaning function promote the facile recovery of the contaminated membrane. Furthermore, the mechanical flexible characteristic of the TiO₂/Fe₂O₃ composite membrane widens its applicability in industrial employment. Thanks to these properties, this novel membrane can be considered as a practical option for treating surfactant‐stabilized oil‐water emulsions.     

Novel Fluorescent Chemosensor for Detection of F− Anions Based on a Single Functionalized Pillar[5]arene Iron(III) Complex

Novel fluorescent chemosensor with good selectivity for F^? anion was designed and synthesized. The sensor has a bearing on a single functionalized pillar[5]arene and Fe³⁺ metal complex (PN‐Fe), which showed prominent fluorescent response for F^? anion over other common anions (Cl^?, Br^?, I^?, AcO^?, HSO4^?, H₂PO₄^?, ClO₄^?, CN^? and SCN^?). These results were evaluated by fluorescent method. The detection limit of PN‐Fe to F^? was calculated to be 2.50×10^?7 mol/L. Moreover, the sensor PN‐Fe³⁺ might serve as a recyclable component in sensing materials.     

Synthesis of Hollow Platinum–Palladium Nanospheres with a Dendritic Shell as Efficient Electrocatalysts for Methanol Oxidation

Engineering the size, composition, and morphology of platinum‐based nanomaterials can provide a great opportunity to improve the utilization efficiency of electrocatalysts and reinforce their electrochemical performances. Herein, three‐dimensional platinum–palladium hollow nanospheres with a dendritic shell (PtPd‐HNSs) are successfully fabricated through a facile and economic route, during which SiO₂ microspheres act as the hard template for the globular cavity, whereas the triblock copolymer F127 contributes to the formation of the dendritic shell. In contrast with platinum hollow nanospheres (Pt‐HNSs) and commercial platinum on carbon (Pt/C) catalyst, the novel architecture shows a remarkable activity and durability toward the methanol oxidation reaction (MOR) owing to the coupled merits of bimetallic nanodendrites and a hollow interior. As a proof of concept, this strategy is also extended to trimetallic gold–palladium–platinum hollow nanospheres (AuPdPt‐HNSs), which paves the way towards the controlled synthesis of other bi‐ or multimetallic platinum‐based hollow electrocatalysts.