Synthesis and characterization of the first carbene derivative of a polyoxometalate

Reaction of the Keggin-type polyanion [PW11O39]7- with the tetrakis-carbene ruthenium precursor [RuLMe4Cl2] (LMe = 1,3-dimethylimidazolidine-2-ylidene), in water, results in the formation of Na4K9[(PW9O34)2(cis-WO2)(cis-RuLMe2)].23H2O, which is the first carbene derivative of a polyoxometalate. The oxidation state of the ruthenium is confirmed by XANES experiments.     

Synthesis and first molecular structure of a bis-2-spiro-1-boraadamantane derivative

[reaction: see text] A new method for synthesizing the 2-spiro-boraadamantane pyridine complex (2) from 1-ethynylcyclohexylmethyl ether has been developed. The chemistry has been applied to the synthesis of bis-2-spiro-1-boraadamantane.pyridine (1) from trans-1,4-diethynyl-1,4-dimethoxycyclohexane (8). This bis-Lewis acid serves as a self-assembling molecular building block with difunctional Lewis bases.     

Biomedical applications of derivative spectroscopy

The value of spectroscopic data can be enhanced by transformation to the second or higher derivative. The impact of this new computer-aided approach in analytical spectroscopy on the biomedical sciences is assessed.     

The enantio- and diastereoselective synthesis of the first phospho-statine derivative

The title compound was synthesized by the diastereoselective addition of the lithium or sodium anion of dimethyl methylphosphonate to $\text{N}$-trityl-L-phenylalaninal.     

Determination of lamivudine and zidovudine in binary mixtures using first derivative spectrophotometric, first derivative of the ratio-spectra and high-performance liquid chromatography-UV methods

Three methods are presented for the simultaneous determination of lamivudine and zidovudine. The first method depends on first derivative UV spectrophotometry, with zero-crossing and peak-to-base measurement. The first derivative amplitudes at 265.6 and 271.6 nm were selected for the assay of lamivudine and zidovudine, respectively. The second method depends on first derivative of the ratio-spectra by measurements of the amplitudes at 239.5 and 245.3 nm for lamivudine and 225.1 and 251.5 nm for zidovudine. Calibration graphs were established for 1-50 μg/ml for lamivudine and 2-100 μg/ml for zidovudine. In the third method (HPLC), a reversed-phase column with a mobile phase of methanol:water:acetonitrile (70:20:10 (v/v/v)) at 0.9 ml/min flow rate was used to separate both compounds with a detection of 265.0 nm. Linearity was obtained in the concentration range of 0.025-50 μg/ml for lamivudine and 0.15-50 μg/ml for zidovudine. All of the proposed methods have been extensively validated. These methods allow a number of cost and time saving benefits. The described methods can be readily utilized for analysis of pharmaceutical formulations. There was no significant difference between the performance of all of the proposed methods regarding the mean values and standard deviations. The described HPLC method showed to be appropriate for simultaneous determination of lamivudine and zidovudine in human serum samples.     

苯并呋喃衍生物的合成和结构表征

天然化合物常表现出各种独特的生物活性,使其成为寻找和筛选各种生物活性物质如医药、农药等的天然宝库.楝酰胺(rocaglamide)(结构式如图式1)是从楝属植物中分离出的具有良好杀虫活性的化合物[1],对疆叶蛾的LC50为0.91μg/mL,与已知的天然杀虫剂苦楝素Azadirachtin(LC50为0.70μg/mL)的活性相当[2-4],这表明楝酰胺有可能成为一种极为重要的天然杀虫剂.     

四硫代富瓦烯衍生物的合成和表征

通过4-二甲氨基吡啶(DMAP)、二环己基碳二亚胺(DCC)催化体系的酯化反应和三乙基磷酸酯的耦合反应得到四硫代富瓦烯衍生物,通过核磁、质谱、红外等手段对所合成的四硫代富瓦烯的衍生物进行了纯度和结构的确认,使用偏光显微镜,差示扫描量热仪等,对其热力学性能和液晶性能进行了表征,证明它是一种室温液晶分子,对它进行了化学氧化实验,研究了四硫代富瓦烯衍生物的氧化还原性质.     

固载脯氨酸的毛发状纳米粒子的合成及其应用研究

毛发状粒子表面的聚合物链是一个具有一定流动性的动态体系,其负载的催化剂综合了均相和非均相负载催化剂的优点,为手性催化剂的负载和实用化提供了一条新的途径。本文利用Si O2纳米粒子表面修饰制得的功能基,通过表面RAFT聚合,并经过氨基去保护后制得负载脯氨酸的毛发状纳米粒子。通过热重、红外和透射电镜对毛发状二氧化硅纳米粒子的结构进行表征,并将获得的毛发状纳米粒子作为催化剂直接催化不对称Aldol反应。     

Triazole-modified triphenylene derivative: self-assembly and sensing applications

Triphenylene-based discotic liquid crystal 3 bearing 1,2,3-triazole groups has been synthesized using "click" chemistry. Discotic mesogen 3 has good thermal stability, and incorporation of triazole groups results in stabilization of columnar mesophases down to room temperature and formation of organogels in cyclohexane and mixed solvents such as hexane and dichloromethane (4:1 v/v). Characterization of the organogel of 3 in cyclohexane revealed a porous network. However, presence of Cd(2+) ions in solution obstructed the self-assembly of this derivative due to preferred interactions between Cd(2+) ions and triphenylene units over π-π interactions among triphenylene groups. Further, strong emission of derivative 3 in its nonaggregated form makes it a promising fluorescence sensory material for nitroaromatic compounds.     

Synthesis of levoglucosenone oxazoline derivative

Russian Journal of Organic Chemistry -     

Synthesis of a novel Boc-protected cyclopropane-modified proline analogue

The synthesis of the Boc derivative of a novel member of the cyclopropane-modified proline library, Boc-protected 5-azaspiro[2.4]heptane-6-carboxylic acid, is reported. The synthesis was performed in six steps starting from (2S,4R)-4-hydroxyproline using a modified Simmons-Smith reaction as the key step. The reaction conditions for all the steps were carefully selected to avoid racemization at the chiral centers in the intermediates and the final product.     

Synchronous scanning first and second derivative spectrofluorimetric determination of the alkaloid berberine

Summary Solvent effects on the spectral characteristics of berberine solutions and their influences on the sensitivity of its spectrofluorimetric determination are discussed. Linear calibration graphs in the ng·ml^–1 range for zero, normal and synchronous first and second derivative are established. The prototropic behaviour of berberine in the ground and excited state was determined and related with the influence of proton motions in the analytical procedure.The influence of reaction variables, instrumental parameters and some interfering substances was studied. The application of the methods to synthetic mixtures is also described.

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Bestimmung des Alkaloids Berberin durch synchrone Scanning-Spektrofluorimetrie mit erster und zweiter Ableitung

Zusammenfassung Lösungsmitteleffekte auf die Spektralcharakteristik von Berberinlösungen und ihr Einfluß auf die Empfindlichkeit der spektrofluorimetrischen Bestimmung werden diskutiert. Lineare Eichkurven im ng/ml-Bereich wurden für die nullte, normale sowie synchrone erste und zweite Ableitung aufgestellt. Das prototrope Verhalten des Berberins im Grund- und angeregten Zustand wurde bestimmt und zum Einfluß der Protonbewegungen in der analytischen Methode in Bezug gesetzt. Der Einfluß der Reaktionsvariablen, der instrumenteilen Parameter sowie von störenden Substanzen wurde untersucht. Die Anwendung auf synthetische Mischungen wird beschrieben.

     

Multidimensional quantum trajectories: applications of the derivative propagation method

In a previous publication [J. Chem. Phys. 118, 9911 (2003)], the derivative propagation method (DPM) was introduced as a novel numerical scheme for solving the quantum hydrodynamic equations of motion (QHEM) and computing the time evolution of quantum mechanical wave packets. These equations are a set of coupled, nonlinear partial differential equations governing the time evolution of the real-valued functions C and S in the complex action, S=C(r,t) + iS(r,t)/Planck's over 2pi, where Psi(r,t)=exp(S). Past numerical solutions to the QHEM were obtained via ensemble trajectory propagation, where the required first- and second-order spatial derivatives were evaluated using fitting techniques such as moving least squares. In the DPM, however, equations of motion are developed for the derivatives themselves, and a truncated set of these are integrated along quantum trajectories concurrently with the original QHEM equations for C and S. Using the DPM quantum effects can be included at various orders of approximation; no spatial fitting is involved; there is no basis set expansion; and single, uncoupled quantum trajectories can be propagated (in parallel) rather than in correlated ensembles. In this study, the DPM is extended from previous one-dimensional (1D) results to calculate transmission probabilities for 2D and 3D wave packet evolution on coupled Eckart barrier/harmonic oscillator surfaces. In the 2D problem, the DPM results are compared to standard numerical integration of the time-dependent Schrodinger equation. Also in this study, the practicality of implementing the DPM for systems with many more degrees of freedom is discussed.     

伊马替尼衍生物的合成及细胞毒活性研究

以3-乙酰基嘧啶、2-甲基-5-硝基苯胺为起始原料,经加成、缩合、环化、还原得到中间体伊马替胺(6),再与异氰酸酯和芳酰基异硫氰酸酯胺解得到脲类(7a~7e)和芳酰基硫脲类(8a~8g)共12个化合物。目标化合物经过IR、1H NMR、13C NMR、HRMS等结构确证。采用四甲基偶氮唑盐(MTT)法考察目标化合物细胞毒活性,结果显示,目标化合物对所选肿瘤细胞的增殖活性具有一定抑制作用,其中化合物7d、7e、8d对人白血病细胞(K562)和人肝癌细胞(Hep G2)的抑制活性接近伊马替尼。     

地塞米松衍生物的合成及其抗肿瘤活性研究

地塞米松(dexamethasone)为人工合成的肾上皮质激素类药物,具有抗炎、应激保护[1],增强化疗药物诱导肿瘤细胞凋亡[2],促进细胞分化[3]等药理作用.     

Synthesis and characterization of the first metallacyclooctane

Ring closing metathesis (RCM) using Grubbs' 1st generation catalyst with cis-[L(2)Pt(CH(2)CH(2)CH[double bond, length as m-dash]CH(2))(CH(2)CH(2)CH(2)CH[double bond, length as m-dash]CH(2))] yields a platinacyclooctene which can be hydrogenated to the platinacyclooctane, L(2)Pt(CH(2))(7) [L(2) = Ph(2)PCH(2)CH(2)CH(2)PPh(2) (dppp) or Ph(2)PCH(2)CH(2)PPh(2) (dppe)] in high yield.