Probing the Anticancer Mechanism of (−)‐Ainsliatrimer A through Diverted Total Synthesis and Bioorthogonal Ligation

Herein, we report an efficient approach for exploring the novel anticancer mechanism of (?)‐ainsliatrimer A, a structurally complex and unique trimeric sesquiterpenoid, through a combined strategy of diverted total synthesis (DTS) and bioorthogonal ligation (TQ ligation), which allowed us to visualize the subcellular localization of this natural product in live cells. Further biochemical studies facilitated by pretarget imaging revealed that PPARγ, a nucleus receptor, was a functional cellular target of ainsliatrimer A. We also confirmed that the anticancer activity of ainsliatrimer A was caused by the activation of PPARγ.     

Synthesis of Polyketide Stereoarrays Enabled by a Traceless Oxonia‐Cope Rearrangement

Polyketide antibiotics bearing skipped polyols represent a synthetic challenge. A SiCl₄‐promoted oxonia‐Cope rearrangement of syn,syn‐2‐vinyl‐1,3‐diols was developed to forge an array of 1,5‐pentenediols, thus providing versatile motifs for the preparation of 1,2,3,5‐stereoarrays in a highly stereoselective manner. Further exploration with Sn(OTf)₂ realized the rearrangement of a cross‐aldehyde which tactically warrants the utility of the current approach to access complex polyketides. The origin of high stereoselectivity is attributed to a chairlike anti‐conformation of the oxonium ion intermediate.     

Improving the Alkaline Stability of Imidazolium Cations by Substitution

Imidazolium cations are promising candidates for preparing anion‐exchange membranes because of their good alkaline stability. Substitution of imidazolium cations is an efficient way to improve their alkaline stability. By combining density functional theory calculations with experimental results, it is found that the LUMO energy correlates with the alkaline stability of imidazolium cations. The results indicate that alkyl groups are the most suitable substituents for the N3 position of imidazolium cations, and the LUMO energies of alkyl‐substituted imidazolium cations depend on the electron‐donating effect and the hyperconjugation effect. Comparing 1,2‐dimethylimidazolium cations (1,2‐DMIm⁺) and 1,3‐dimethylimidazolium cations (1,3‐DMIm⁺) with the same substituents reveals that the hyperconjugation effect is more significant in influencing the LUMO energy of 1,3‐DMIms. This investigation reveals that LUMO energy is a helpful aid in predicting the alkaline stability of imidazolium cations.     

Optoelectronic and Self‐assembly Properties of Porphyrin Derivatives with Click Chemistry Modification

A series of functionalized porphyrin molecules containing electron‐rich alkynes, synthesized by means of the Sonogashira coupling reaction were further modified by reacting the ethynyl groups with click reagent through a formal [2+2] click reaction. The photophysical and electrochemical properties of the porphyrin derivatives were studied by UV/Vis spectroscopy and cyclic voltammetry. We show that the optoelectronic properties are affected by the click reagent groups and central metal ions. The functionalized porphyrin molecules show strong charge‐transfer (CT) bands in the visible region (near‐IR region) and potent redox activities. Through a phase‐exchange self‐assembly method, the highly organized morphologies were observed by scanning electron microscopy (SEM). The functionalized porphyrin molecules represent an interesting set of candidates for optoelectronic device components. The effect of the metal ions or click reagent groups on the self‐assembly properties were also studied by the UV/Vis spectroscopic titration experiments.     

流动注射-分光光度法测定药物中克林霉素磷酸酯的含量

试验表明:在pH 3.8的乙酸盐缓冲介质中,克林霉素磷酸酯(CLP)能将铁(Ⅲ)还原为铁(Ⅱ),而所生成的铁(Ⅱ)与邻菲啰啉反应生成有色络合物(λmax=508nm),且生成的铁(Ⅱ)量与CLP之间存在定量关系,经换算所测得吸光度与CLP的质量浓度在0.70~140mg·L-1之间呈线性关系。据此并结合流动注射技术(FI)提出了FI-分光光度法间接测定药物中CLP的新方法优化的分析条件如下:①乙酸盐缓冲溶液的加入量:2.5mL;②铁(Ⅲ)溶液质量浓度:10.0mg·L-1;③邻菲啰啉溶液浓度:1.5×10-3 mol·L-1;④反应温度:85℃。该方法的检出限为0.060mg·L-1。应用此方法测定了药物中CLP的含量,测定值与国家药品标准方法的测定值相符。     

Diastereoselective Synthesis of Functionalized Tetrahydropyrimidin‐2‐thiones via ZnCl2 Promoted One‐pot Reactions

In the presence of zinc chloride, the in situ generated β‐enamino ester from the reaction of morpholine, piperidine and pyrrolidine with methyl propiolate reacted, with aromatic aldehydes and thiourea in ethanol resulting in the functionalized tetrahydropyrimidin‐2‐thiones in satisfactory yields and with good diastereoselectivity. When aromatic aldehydes bearing electron‐withdrawing group were used in the reaction, the 4‐hydroxytetrahydropyrimidin‐2‐thione derivatives were obtained as the main product.     

固载化烷基咪唑离子液体对盐酸体系中Fe(Ⅲ)的吸附性能研究

分别将N-甲基咪唑和N-丁基咪唑通过共价键固定于树脂载体上,制备了固载化甲基咪唑离子液体(MCl)和固载化丁基咪唑离子液体(BCl),MCl和BCl可作为一种新型的强碱型阴离子交换树脂。研究了MCl和BCl对盐酸体系中Fe(III)的吸附性能,其吸附平衡时间为6h,拟二级动力学模型能更好地描述MCl和BCl对Fe(III)的吸附动力学过程;随着温度的升高,MCl和BCl对Fe(III)的吸附量增大,表明该过程是一个吸热反应,在298K时,MCl和BCl对Fe(III)的最大吸附量分别为24.9mg/g和71.1mg/g;随着盐酸浓度的增加,MCl和BCl对Fe(III)的吸附量增大,而且溶液中Cl-浓度的增加,也会提高MCl和BCl对Fe(III)的吸附量。MCl和BCl可从盐酸体系中回收Fe(III),而且BCl的效果要优于MCl。     

Pollution characteristics of ambient PM2.5-bound PAHs and NPAHs in a typical winter time period in Taiyuan

The pollution characteristics of ambient fine particulate matter（PM2.5） containing polycyclic aromatic hydrocarbons（PAHs） and nitrated PAHs（NPAHs） in samples collected during a typical winter time period in Taiyuan of China were investigated.The obtained results revealed that the mean mass concentrations of PM2.5,SPAHs（sum of 16 PAHs） and SNPAHs（sum of 3 NPAHs） on PM2.5were161.4 mg/m3,119.8 ng/m3and 0.446 ng/m3,respectively.Diagnostic ratios of PAHs and NPAHs implied that coal consumption might be the main source of the PM2.5pollution.The measured PM2.5mass concentrations,BaP equivalent toxicity（28.632 ng/m3） and individual carcinogenicity index（3.14 10 5） were much higher than those of the recommended safety standards.     

Allyl phthalazinone synthesis,polymerization and polymer properties

A phthalazinone monomer with an allyl group, i.e. 4-（3-allyl-4-hydroxyphenyl）phthalazin-1（2H）-one, was synthesized and then copolymerized with 4-（4-hydroxylphenyl）（2H）-phthalazin-1-one and 2,6- diflurobenzonitrile by means of aromatic nucleophilic polycondensation to provide a series of crosslinkable poly（aryl ether nitrile）s. The virgin copolymers exhibited good solubility in polar organic solvents with relative high molecular weights （Mw： 45,130-58,403, inherent viscosities： 0.58-0.75 dL/ g）. After cross-linking, the thermal stability and solvent resistance of the polymer increased.     

Chemoselective hydrogenolysis of tetrahydrofurfuryl alcohol to 1,5-pentanediol over Ir-MoOx/Si02 catalyst

In this work, MoOx promoted Ir/SiO2 catalysts were prepared and used for the selective hydrogenolysis of tetrahydrofurfuryl alcohol （THFA） to 1,5-pentanediol in a continuous flow reactor. The effects of different noble metals （Ir, Pt, Pd, Ru, Rh）, supports and Ir contents were screened. Among the investigated catalysts, 4 wt%Ir-MoOx/SiO2 with a Mo/Ir atomic ratio of 0.13 exhibited the best catalytic performance. The synergy between Ix particles and the partially reduced isolated MoOx species attached on them is essential for the excellent catalytic performance of Ix-MoOx/SiO2. The catalyst exhibited a better hydrogenolysis efficiency of THFA with the selectivity of 1,5-pentanediol of 65%-74% at a conversion of THFA of 70%-75% when the initial THFA concentration is ranging from 20 wt% and 40 wt%. And higher system pressure was also in favor of the conversion of THFA. During a stability test, the conversion of THFA and 1,5-pentanediol yield over Ix-MoOz/SiO2 decreased with reaction time, which can be explained by the leaching of Mo species during the reaction.