茯苓菌核多糖的分离和结构分析

分别用０．９％ＮａＣｌ不溶液，热水，０．５ｍｏｌ／Ｌ ＮａＯＨ水溶液和８８％甲酸从新鲜茯苓菌核体中提取出５种多糖：ＰＣ１，ＰＣ２，ＰＣ２－Ａ，ＰＣ３和ＰＣ４．用ＩＲ，ＨＰＬＣ，ＧＣ，＾１ＨＮＭＲ和＾１３Ｃ ＮＭＲ等方法分析了它们的组成和结构。结果表明，ＰＣ１，ＰＣ２和ＰＣ２－Ａ由Ｄ－葡萄糖，Ｄ－木糖，Ｄ－甘露糖和Ｄ－半乳糖组成，ＰＣ１和ＰＣ２－Ａ含葡萄糖醛酸，其葡萄糖含量随提取过程的进行逐渐增加。     

抑制动力学分析法测定痕量铈

１引言研究了铈（Ⅲ）阻抑Ｈ２Ｏ２氧化水杨基荧光酮（ＳＡＦ）褪色的反应。反应对铈（Ⅲ）为一级反应，表观活化能为２８．７５ｋＪ／ｍｏｌ。据此建立了测定痕量铈的动力学分析法。测定条件为：ＳＡＦ：４．０ｘ１０－５ｍｏｌ／Ｌ，Ｈ２Ｏ２：０．０１０％，ＮａＯＨ：２．０ｘ１０－２ｍｏｌ／Ｌ，５０℃。线性范围０．０４～０．４４ｍｇ／Ｌ，检测限为０．０２ｍｇ／Ｌ。当溶液中的铈含量为０．１６ｍｇ／Ｌ时，３～８倍量的轻稀土，５～１１倍量的重稀土及同倍量铀和钍不干扰测定。２实验部分２．１试剂和仪器铈（Ⅲ）标准溶液：２０…     

芦荟大黄素的电化学研究

用单扫示波极谱法研究了芦荟大黄素的电化学行为。在５％Ｎａ２ＣＯ３＋５％ＮａＯＨ（９＋１）底液中，芦荟大黄素于－０．８４Ｖ（Ｐ１）和－０．９７Ｖ（Ｐ２）处产生两个示波极谱峰，利用Ｐ１可测定芦荟大黄素，线性范围为 ０．１１－２４ｍｇ／Ｌ和３．０－２８．６ｍｇ／Ｌ，检测限为０．０６ｍｇ／Ｌ。将该法应用于中药大黄中的芦荟大黄素的测定，结果满意。另外，讨论了芦荟大黄素清除由邻苯三酚自氧化产生的超氧自由基（Ｏ２）的作用。     

硼掺杂多晶金刚石薄膜电极的电化学特性

用循环伏安法和恒电位法研究了硼掺杂多晶金刚石薄膜电极（ＤＦＥ）的若干电化学特性。电极面积４×４ｍｍ＾２。在０．１ｍｏｌ／Ｌ ＫＣｌ，ＮａＮＯ３，ＮａＯＨ和ＫＨ２ＰＯ４＋Ｎａ２ＨＰＯ４（ｐＨ＝６．８６）电解质溶液中电势窗口均为－５００￣＋８００ｍＶ；而在０．１ｍｏｌ／Ｌ ＨＣｌ和Ｈ２ＳＯ４溶液中电势窗口为－２００￣＋１１００ｍＶ．Ｋ３Ｆｅ（ＣＮ）６的氧化峰电位为＋５００ｍＶ，与Ｐｔ电极测量相同；校正     

四磺基铁酞菁做为过氧化物模拟酶在过氧化氢及葡萄糖测定中的应用

以四磺基铁酞菁（ＦｅＴＳＰｅ）作为过氧化物模拟酶催化Ｈ２Ｏ２与Ｌ－酪氨酸的荧光反应,建立了测定宽含量范围的Ｈ２Ｏ２及葡萄糖的方法。该法的线性范围为０．０－８．０×１０＾５ｍｏｌ／Ｌ,Ｈ２Ｏ２及０．０￣２．０×１０＾－４ｍｏｌ／Ｌ葡萄糖,检测限分别为５．０×１０＾－８ｍｏｌ／Ｌ及６．０×１０＾－６ｍｏｌ／Ｌ,将该经酶催化反应偶联,测定人血清中葡萄糖的含量,取得了满意的结果。     

葡萄糖脱氢酶微型生物传感器的研制及应用

以甲苯胺兰（ＴＢ）修饰碳糊微电极为基体，将葡萄糖脱氢酶（ＧＤＨ）用丝素蛋白膜固定于修饰微电极表面制成了生物传感器，在ｐＨ７．０的ＮａＯＨ－ＮａＨ２ＰＯ４缓冲溶液中，烟酰胺腺嘌呤二核苷酸（ＮＡＤ）的浓度为１．０４×１０＾－３ｍｏｌ／Ｌ的条件下，其响应电流与葡萄糖浓度在１．０×１０＾－４～３．２×１０＾－３ｍｏｌ／Ｌ范围内有良好线性关系，响应时间为２０ｓ；检测限为４．０×１０＾－５ｍｏｌ／Ｌ。该传感器     

流动注射—原子吸收法测定药物制剂中的维生素B6

１引言在弱酸性介质中，新生态ＭｎＯ２与维生素Ｂ６（ＶＢ６）发生反应，通过ＦＩＡ－ＡＡＳ测定反应产物Ｍｎ２＋，建立了测定ＶＢ６含量的新方法。方法具有简便、快速、重现性好等优点，用于实际样品的测定，结果与药典法一致。２实验部分２．１仪器与试剂ＧＦＵ－２０２型原子吸收分光光度计；ＩＦＩＳ－Ｂ型智能流动注射进样器；Ｍｎ２＋标准溶液（１ｇ／Ｌ）；ＶＢ６标准溶液（１ｇ／Ｌ）；新制ＭｎＯ２＋：在０．２５％ＫＭｎＯ４溶液中逐滴加入０．５％ＭｎＳＯ４（其中含硫酸１ｍｏｌ／Ｌ）至红色完全消失。新制得的ＭｎＯ２保存在…     

用2—羟基—3—羧基—5—磺酸基苯重氮氨基偶氮苯流动注射分光光度法测定汞

研究了在乳化剂ＯＰ存在下，２－羟基－３－羧基－５－磺酸基苯重氮氨基偶氮苯（ＨＣＳＤＡＡ）－汞（Ⅱ）显色体系流动注射分光光度法。用ＰＨ１０．０－１０．５的Ｎａ２Ｂ４Ｏ７－ＮａＯＨ缓冲溶液作载流，汞（Ⅱ）与ＨＣＳＤＡＡ和乳化剂ＯＰ的混合试剂反应形成红色络合物。用于测定汞时，方法的线性范围是０．０５－１．０ｍｇ／Ｌ，检测限为０．０１６ｍｇ／Ｌ，进样频率为１００样／ｈ。直接应用于头发、自来水和废水中微量汞     

催化动力学光度法测定痕量苯酚

研究了在硫酸介质中苯酚对Ｉ＾－１催化Ｃｅ＾４＋－Ａｓ（Ⅲ）反应的抑制作用及其动力学条件。建立了用催化动力这光度法测定痕量苯酚的新方法，结果表明，在０．００１ｍｏｌ／ＬＣｅ（ＳＯ４）２，０．００１２５ｍｏｌ／Ｌ，Ａｓ２Ｏ３，０．０１ｍｇ／Ｌ，ＫＩ，０．０１２５ｍｏｌ／Ｌ，Ｈ２ＳＯ４和０．１３％（ｗ／ｖ）ＮａＣｌ溶液中测定苯酚，其表面摩尔吸光系数为２．１×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，线性范围     

CONVERSION OF METHANE AND CARBON DIOXIDE TO AROMATICS OVER CHROMIUM-BASED CATALYSTS:SELECTIVITY AND YIELD OF MAIN PRODUCTS

在８４０℃，０．５ＭＰａ，ＣＨ４／ＣＯ２摩尔比为１．４，接触时间（Ｗ／Ｆ）为０．７９ｈ·ｇ·Ｌ－ｌ的条件下，甲烷和二氧化碳在７．５ｗｔ％Ｃｒ／５．０ｗｔ％Ｎａ／ＳｉＯ２催化剂上共活化得到了４．８％的Ｃ２选择性，４８．７％的芳烃选择性及１．９％的芳烃收率。在钠修饰的铬基催化剂上，成功地一步实现了ＣＨ４和ＣＯ２转化为乙烯及中间物乙烯聚合为芳烃的过程     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

Catalyst free,visible-light promoted photoaddition reactions between C60 and N-trimethylsilylmethyl-substituted tertiary amines for synthesis of aminomethyl-1,2-dihydrofullerenes

An efficient and benign method for the preparation of aminomethyl-substituted fullerenes has been developed. The process, involving catalyst free, visible-light irradiation of 10% EtOH-toluene solutions containing fullerene C₆₀ and N-trimethylsilylmethyl-substituted amines by using a 20 W compact fluorescent lamp, leads to formation of aminomethyl-substituted fullerene adducts in a highly efficient manner. The photoaddition reaction takes place via a pathway initiated by visible light absorption by C₆₀, followed by SET from the amine to the triplet excited state of C₆₀. Ethanol-promoted desilylation of the resulting a minimum radical then generates the corresponding α-amino radical which couples with the C₆₀ radical anion to form the anion precursor of the fullerene adducts. The new approach using visible-light takes place under mild conditions and it does not require the use of photocatalysts. Thus, the method developed in this effort could broadens the range of functionalized fullerene derivatives that can be readily prepared.     

Highly efficient and stereoselective cycloaddition of nitrones to indolyl- and pyrrolylacrylates

The reactions of various nitrones with indolyl- and pyrrolylacrylates proceeds regioselectively with high diastereoselectivity in the case of aldonitrones, and represents an effective method for obtaining new indolyl- and pyrrolyl-substituted isoxazolidine carboxylates stabilized by weak (CH?O) and moderate (NH?N) strength intramolecular hydrogen bonding. The resulting cycloadducts exhibit promising in vitro anti-influenza activities.     

Transition metal-free direct amination of benzoxazoles using formamides as nitrogen sources

A transition metal-free method for the direct amination of benzoxazoles using formamides as nitrogen sources is reported, which was mediated by an inexpensive and environmentally friendly tetrabutylammonium iodide/tert-butyl hydroperoxide system and gave the 2-aminobenzoxazole derivatives with moderate to good yields.     

l-Proline-catalyzed five-component domino reaction leading to multifunctionalized 1,2,3,4-tetrahydropyridines

Multifunctionalized 1,2,3,4-tetrahydropyridines are concisely synthesized in good yields via l-proline-catalyzed or l-proline/FeCl₃-cocatalyzed one-pot multicomponent reactions (MCRs). The MCRs involve a domino hydroamination/prins reaction/Mannich-type reaction/intramolecular dehydration-cyclization process. The molecular structure of 5baa, one of multifunctionalized 1,2,3,4-tetrahydropyridines, was confirmed by single-crystal X-ray diffraction.     

Exploring the scope of the Gewald reaction: Expansion to a four-component process

An efficient four-component reaction was developed to take advantage of the reactivity of the 2-aminothiophene-3-carbonitrile functionality, which is obtained during the classical three-component Gewald reaction. Various α-methylene bearing ketones were reacted with malononitrile, elemental sulfur, and aryl/heteroarylnitrile derivatives in t-BuOH/NaOH to afford 2-arylthieno[2,3-d]pyrimidin-4-amines in high yields. Preliminary studies revealed the photophysical properties of the products and their potential for use as metal sensors.