Convenient access to sterically hindered C2 chiral 2,2,5,5-tetraphenyltetrahydrofuran-3,4-diols: intramolecular selective 1,4-cyclocondensation of (2R,3R)- and (2S,3S)-1,1,4,4-tetraphenylbutanetetraols

Sterically hindered C₂ chiral (3R,4R)- and (3S,4S)-2,2,5,5-tetraphenyltetrahydrofuran-3,4-diols have been conveniently prepared in a very high yield via heterogeneous intramolecular selective 1,4-cyclocondensation of (2R,3R)- and (2S,3S)-1,1,4,4-tetraphenylbutanetetraol in concentrated hydrohalic acids, respectively. Preliminary examination of additives for the Barbas–List reaction showed that in certain cases, the hindered C₂ chiral tetrahydrofuran-3,4-diols were better chiral auxiliaries than enantiopure (R)- and (S)-1,1′-bi-2-naphthols.     

Covalent Organic Frameworks with trans-Dimensionally Vinylene-linked π-Conjugated Motifs

Vinylene-linked covalent organic frameworks(COFs) are a class of promising porous organic materials that feature fully π-conjugated structures, high crystallinity, permanent porosity, ultrahigh chemical stability, and extraordinary optoelectronic properties. Over the past 5 years, this kind of material has been witnessed rapid development either in chemical synthesis or in potential applications. In this review, we summarize the chemistry to synthesize vinylene-linked COFs, especially the synthetic strategies involving activation of aryl methyl groups for condensation reaction. We then scrutinize the state-of-the-art development in properties and functions of this kind of COFs. Our own opinions on the further development of the vinylene-linked COFs are also presented for discussion.     

硼化合物的研究(Ⅳ)——硼烷阴离子铵盐的合成与性质

通过硼烷阴离子网-B₃H₈^-和闭-B₁₀H₁₀^2-与一系列卤化铵反应合成出十五种新的硼烷阴离子铵盐。这些新化合物均经元素分析和红外光谱鉴定。它们的差热分析结果表明:B₁₀H₁₀^2-铵盐的热稳定性高于B₃H₈^-铵盐;在季铵离子中导入氨基以后,化合物的热稳定性降低,并且导入的氨基愈多,化合物愈不稳定。     

Synthesis and Evaluation of Novel α-Aminoamides Containing Benzoheterocyclic Moiety for the Treatment of Pain

Novel α-aminoamide derivatives containing different benzoheterocyclics moiety were synthesized and evaluated as voltage-gated sodium ion channels blocks the treatment of pain. Compounds 6a, 6e, and 6f containing the benzofuran group displayed more potent in vivo analgesic activity than ralfinamide in both the formalin test and the writhing assay. Interestingly, they also exhibited potent in vitro anti-Na_v1.7 and anti-Na_v1.8 activity in the patch-clamp electrophysiology assay. Therefore, compounds 6a, 6e, and 6f, which have inhibitory potency for two pain-related Na_v targets, could serve as new leads for the development of analgesic medicines.     

A Novel Automated Online SPE-Coupled CE System for the Analysis of Sulfonamide Antibiotics in Wastewater

A novel automated online SPE-coupled CE system with high precision has been developed, in which a four-port nano-valve served as an interface. With this system, 10 mL of pretreated water sample was introduced to the online SPE column, and the analytes were preconcentrated. After the cleanup step, the analytes were eluted, and a quantitative volume of the elution plug was injected in the capillary by switching the four-port nano-valve for CE separation. The experimental parameters, including the position of the four-port nano-valve, separation conditions, sample loading flow rate, sample volume, elution flow rate and four-port nano-valve switch time were optimized in detail. The effectiveness of the system was demonstrated by the analysis of six sulfonamide antibiotics in water samples. Good linear ranges were obtained with correlation coefficients from 0.9983 to 0.9997. The intra- and inter-day relative standard deviations were below 4.6 and 5.8%, respectively. The limits of detections were in the range of 2.22 to 3.35 ng mL^?1. This proposed method was successfully applied to the analysis of effluent and influent water from a wastewater treatment plant, and the average recoveries of the wastewater samples ranged from 77.3 to 92.0%.     

An improved and practical approach to essentially enantiopure BINOLs: enantioselective inclusion complexation of (S)-proline

An improved and practical approach to (R)- and (S)-BINOLs has been developed. The rac-BINOL and (S)-proline were refluxed in acetonitrile for several hours, and the resulting white precipitate was recrystallized in ethanol to afford colorless crystals consisting of (S)-BINOL and (S)-proline, which were analyzed by single crystal X-ray structural analysis. Essentially enantiopure (S)- and (R)-BINOLs were obtained in high yields after decomposition of the colorless crystalline complex and evaporation of the acetonitrile mother liquor removed from the complex precipitate and successive crystallization. The (S)-proline can be recovered and reused without any decrease in efficiency.     

相依删失下基于连接函数的参数模型的统计分析

在临床数据的收集中,由于竞争性风险或者病人的退出可能导致数据删失.删失数据的统计分析大多是基于独立删失的假定进行的.而实际情况中,数据的删失往往是非独立的,即删失变量和失效时间变量是相关的.相依删失使得原本复杂的删失数据处理变得更加困难.在本文中,假定删失变量和失效时间变量的联合分布可以用它们边际分布的连接函数函数表示,在给定连接函数下,得到了比例风险模型的极大似然估计.模拟计算显示,如果删失假定成立,本文所采用方法比独立删失假定下的估计方法更准确.     

轴对称超形变和三轴超形变核态性质的研究

利用轴对称超形变和三轴超形变模型研究了¹⁶⁵Lu π[660 1/2]带.两种模型计算的γ跃迁能量都和实验值较好地符合.然而,能量的signature颤动指数,三轴因子,两类动力学电四极矩之比存在明显的差别,这些差别可以用来识别三轴超形变核态.     

一些多官能生物碱的硼烷配合物的合成与结构表征

研究了多官能生物碱辛可宁、辛可尼定和奎宁与Ｈ３Ｂ·Ｓ（ＣＨ３）２的反应；其产物组成和结构与反应物配比有关．在实验条件下，生物碱与Ｈ３Ｂ·Ｓ（ＣＨ３）２等摩尔反应生成单甲硼烷配合物；在Ｈ３Ｂ·Ｓ（ＣＨ３）２过量时，最多只能得到含两个硼原子的化合物，生物碱分子中的烯键对Ｈ３Ｂ·Ｓ（ＣＨ３）２表现出惰性．