Simultaneous Determination of Gold and Platinum by Double Artificial Neural Network Analysis with Flow-injection Chemiluminescence

Chemiluminescence (CL) is well known to be an important and powerful analytical technique owing to its lower detection limits, higher sensitivity and wider linear ranges can be achieved with simpler instrument1. CL analysis has been used for determination…     

Determination of Amino Acids in Single Human Lymphocytes after On-capillary Derivatization by Capillary Zone Electrophoresis with Electrochemical Detection

Sensitive and selective methods for the detection of amino acids (AAs) in single cells are of increasing importance. Capillary zone electrophoresis (CZE) with electrochemical detection (ED) is suitable for analysis of electroactive contents in single cells. However, most native AAs have no electroactivity. Derivatization with an electroactive tag is an attractive method. An on-capillary derivatization scheme was reported1. Naphtha- lene-2, 3-dicarboxaldehyde (NDA) can react with pri…     

First Total Synthesis of an Analogue of (±)-Hypargenin B

Hypargenin B, a diterpene with the abietane skeleton, was isolated by Ayhan from the root of an endemic species salvia hypargenia and showed antibacterial activity1. In this diterpene, the junction of A/B ring is trans. In order to provide for studying further the relationship between the structure and bioactivities, we develop a novel route whereby the hypargenin B methyl ether 22 could be obtained in good yield. To our knowledge no total synthetic work has been reported on the title com…     

Study on the Interaction between Distamycin Analogs and DNA from Herring Sperm by Fluorimetry

Distamycin is a naturally occurring antibiotic which binds to the AT rich regions in minor groove of DNA1. We have reported the interaction between the analogs and calf thymus DNA by circular dichroism spectropolarimetry (CD) and isothermal titration calorimetry (ITC)2. Due to the greater sensitivity of fluorescence-based techniques in comparison with CD, we employ the fluorimety to explore the interaction between four new distamycin analogs and DNA from herring sperm. O2NNNOHNNO…     

Synthesis of (1H)-3,4-Dihydropyrrolo[2,1-c][1,4]oxazin-1-one Derivatives

It has been found that some acyl derivatives of 1,2,3,4-tetrahydro-1-indolizin-1-one 1and (1H)-3,4-dihydropyrrolo[1,2-a]pyrazin-1-one 2 show remarkable anti-inflammatory and analgesic activities1,2. The interest in extending the study of structure-activity relationships and search of new potent anti-inflammatory and analgesic agents led us to design and synthesize (1H)-3,4-dihydropyrrolo[2,1-c][1,4]oxazin-1-one 3 derivatives. NO 1 NNHO2 87654321ONO3 A few examples of the p…     

Preliminary Study on Pyrolysis of Polymethylsilsesquioxane by FT—IR and XPS

The term polysilsesquioxanes in this paper refers to all structures with the empiri-cal formulas (RSiO3/2)n where R is hydrogen or any alkyl, alkylene, aryl, arylene, or organo-functional derivatives of alkyl, alkylene, or aryl. Polymethylsilsesquioxane (PMSQ) is characterized by its low weight loss at high temperatures. X-ray photoelectron spectroscopy (XPS) characterization of PMSQ was unavailable from reported literatures. In this study, the pyrolysis was carried out in an inert at…     

Biotransformation of 14-Deacetoxy-13-oxo sinenxan A by Ginkgo Cell Cultures

Sinenxan A, 2a, 5a, 10b,14b-tetraacetoxy-4(20),11-taxadiene, is a taxoid isolated from the callus cultures of Taxus spp. in high yield (ca. 1~2% of dry weight)1,2. The rich resources and its taxane-skeleton vest it valuable potential for the semisynthesis of paclitaxel or other structurally related bioactive compounds, such as 搒econd -generation?taxoid anticancer agents and taxane-based multidrug resistant anticancer agents3-5. Many remarkable studies on its structural modification by chemi…     

Diastereoselective α-Alkylation of β-Amino Esters: Preparation of Novel α-Substituted β-Amino Esters from α-Amino Acids

b-Amino acids and their derivatives have attracted considerable attention in recent years due to their occurrence in biologically active natural products, such as dolastatins 11, cyclohexylnorstatine 22 and taxol 33. bAmino acids also find application in the synthesis of blactams4, piperidines5, indolizidines6. Moreover, the peptides consisting of bamino acids, the so called bpeptides, have been extensively studied recently7. Consequently, considerable efforts have been directed to the synt…     

Studies on the Catalytic Properties of Magnesia Supported on γ-Alumina

ＩｎｔｒｏｄｕｃｔｉｏｎＧｌｙｃｏｌｅｔｈｅｒｓａｒｅｉｍｐｏｒｔａｎｔｉｎｄｕｓｔｒｉａｌｄｅｒｉｖａｔｉｖｅｓｏｆｅｐｏｘｉｄｅｓ .Ｐｏｌｙｅｔｈｙｌｅｎｅ ｇｌｙｃｏｌｅｔｈｙｌｅｔｈｅｒｓａｎｄｐｏｌｙｐｒｏｐｙｌｅｎｅｇｌｙｃｏｌｅｔｈｙｌｅｔｈｅｒｓａｒｅｔｗｏｉｍｐｏｒｔａｎｔｓｅｒｉｅｓｏｆｐｒｏｄｕｃｔｓ .Ｇｌｙｃｏｌｅｔｈｅｒｓａｒｅｇｏｏｄｓｏｌｖｅｎｔｓｄｕｅｔｏｔｈｅｐｒｅｓｅｎｃｅｏｆ—Ｏ—ａｎｄ—ＯＨ ｇｒｏｕｐｓ.Ａｓａｒｅ ｓｕｌｔ ,ｔｈｅｙａｒｅｗｉｄｅｌｙｕｓｅ…     

羟基自由基对多壁碳纳米管表面和结构的影响

碳纳米管纯化后，使用Fenton试剂产生羟基自由基对碳管进行改性处理，研究羟基自由基对碳管表面和结构的影响，并与碳管的混酸处理结果进行比较。FTIR结果表明：经Fenton试剂化学处理后，碳管表面主要引入羟基和羰基，而混酸能“剪切”碳管，产生大量羧基和羰基等官能团。根据Fenton试剂产生羟基自由基的机理，分析了Fenton试剂处理条件的影响因素，控制反应条件即过氧化氢与亚铁离子物质的量之比保持在10左右，而pH值则维持在3左右，对碳管进行改性处理。依据碳管Fenton试剂处理前后的FTIR谱图变化，初步探讨了羟基自由基与多壁碳纳米管作用的可能机理。机理分析表明，改性后碳管表面的羟基和羰基是羟基自由基对碳管上的不饱和键进行加成氧化的结果。