皂土修饰碳糊电极的电化学发光特性研究及其分析应用

基于皂土修饰碳糊电极对鲁米诺背景电化学发光信号的降低作用和对异烟肼的富集分离作用,建立了一种灵敏度高、选择性好的测定异烟肼的电化学发光新方法.在最佳的实验条件下,相对电化学发光强度与异烟肼的浓度在5.0×10^-9～8.0×10^-7mol/L范围内呈线性关系,方法的检出限为1.8×10^-9mol/L,相关系数为0.9984.     

Multisymplectic Structure－Preserving in Simple Finite Element Method in High Dimensional Case

In this paper, we study a finite element scheme of some semi-linear elliptic boundary value problems in high-dhnensjonal space. With uniform mesh, we find that, the numerical scheme derived from finite element method can keep a preserved multisymplectic structure.     

簇状纳米二氧化锰修饰玻碳电极电化学发光法测定己烯雌酚

基于簇状纳米二氧化锰可显著增强玻碳电极的导电性能,且己烯雌酚在该电极上能够增强鲁米诺体系的电化学发光,据此建立了电化学发光测定己烯雌酚的新方法。采用壳聚糖包覆的方法将簇状纳米二氧化锰固定在玻碳电极表面,考察了电极的稳定性以及影响电化学发光的因素。己烯雌酚浓度在3.5×10-11~6.5×10-9mol/L范围内,与电化学发光信号呈良好线性关系;检出限(3σ)为2.0×10-11mol/L。对4.0×10-10mol/L己烯雌酚进行11次平行测定,相对标准偏差(RSD)为1.1%。     

流动注射光纤动力学荧光法测定锰──锰-二元荧光配合物-高碘酸钠体系

对二元荧光配合物作为动力学反应指示剂的可行性进行了考察,以8-羟基喹啉-5-磺酸铝-高碘酸钠为指示反应,建立起流动注射光导纤维光谱技术测定痕量锰(Ⅱ)的动力学荧光分析新体系.此法线性范围为5～200ng/mL,检出限为1ng/mL,对50ng/mL锰(Ⅱ)进行11次测定的相对标准偏差为0.5%,分析速度为45样次/h.     

Total Synthesis of Suberitines A–D Featuring Tunable Biomimetic Late-Stage Oxidative Dearomatization and Acetalization

Aaptaminoids are a unique family of marine alkaloids bearing a benzo[de][1,6]-naphthyridine core. This work describes the first total synthesis of suberitines A–D ( 1 – 4 ), four typical dimeric natural aaptaminoids, employing a step-saving bidirectional strategy. Key methods applied in the total synthesis include a cationic cascade to construct the bis-isoquinoline(s) with Hendrickson reagent-mediated Friedel-Crafts-type cyclization and eliminative aromatization, and a Bronsted acid-promoted Vilsmeier cyclization to generate the naphthyridine(s). The conditionally tunable PIDA-mediated oxidative dearomatization and subsequent methanolysis or hydrolysis successfully served as a powerful biomimetic tool to elaborate the essential oxygenated functionalities of suberitines A–D ( 1 – 4 ) in proper solvent-combinations at the final stage of total synthesis. The biomimetic proposal employed in the late-stage redox interchanges of related natural products was eventually supported by the isolation of synthetic intermediate 23 a as a natural product from the same natural source. Biological screening revealed that five of the synthetic samples including two natural suberitines and three full-skeleton natural product-like intermediates exhibited low micromolar inhibitory activities against the growth of cancer cell line K562.     

Diastereoselective Access to Tetracyclic Eight-Membered Lactams through a Dearomative Heck Reaction and an Alkylative Ring-Opening Driven by Photoexcited Spiroindolines

An external-photocatalyst-free, light-driven alkylative ring-opening of stable spiroindolines was developed to construct indolo- and benzoannulated eight-membered lactams. The spiroindolines were prepared from tetrahydro-β-carbolines by a dearomative Heck reaction. Mechanistic experimental studies on the alkylative ring opening suggested that a photoredox pathway was involved, in which the spiroindoline performed as both reagent and photosensitizer. DFT calculations showed that the radical addition toward a cyclic alkene was the key to the diastereoselective formation of tetracyclic medium-sized lactams.     

青蒿素的生物素标记衍生物的合成

青蒿素1及其衍生物具有特征的过氧桥结构, 并呈现优秀的抗疟生物活性. 为了研究详细的作用机制和确定生物学作用靶标, 本研究从易得的青蒿素衍生物出发, 通过酰胺键相连, 合成了生物素标记的青蒿素衍生物.     

碳纳米管/Nafion-吡啶钌修饰电极电化学发光法测定激动素

实验发现激动素对固定于碳纳米管/Nafion复合膜修饰电极上的吡啶钌弱电化学发光信号有强的增敏作用,基于此建立了一种高灵敏的电化学发光直接测定激动素的新方法.在优化的实验条件下,本方法测定激动素的线性范围为5.0×10-8～4.0×10-5g/L;检出限为2.0×10-8 g/L;相对标准偏差(RSD)为5.8% (n=11, c=5×10-6 g/L);方法操作简单方便,灵敏度高.     

二磺酰胺基溴化硼促进下溴代乙酸酯与吲哚甲醛的缩合反应中底物醛的电子效应

研究了二磺酰胺基溴化硼存在下溴代乙酸叔丁基酯对吲哚α或β甲醛的缩合反应，发现其产物与醛基的位置有密切的联系；同时吲哚氮原子的保护基性质也对产物有较大影响。     

Metal-free synthesis of alkynyl imines using an oxophosphonium-mediated approach at ambient temperatures

A metal-free approach was developed for the mild synthesis of N-aryl α-alkynyl imines from corresponding amide precursors for the first time. The electronic effects of substrates and the reaction mechanisms were investigated and discussed. This newly developed oxophosphonium-triggered one-pot multiple-step method presents the advantages of mild conditions, ease of operation and satisfactory efficiency.