火焰原子吸收光谱法间接测定饲料预混硒中硒

研究了用火焰原子吸收光谱法间接测定饲料预混硒中硒，与其它方法比较，简单、快速，测定的相对标准偏差小于5．0％，回收率为96．3％-104．0％，检出限为0．0005％。     

离子交换分离—氢化物原子吸收光谱法测定紫铜中微是量硒

采用阳离子交换树脂离子分离铜，发生氢化物原子吸收光谱法测定硒，上柱溶液酸度在０－７％，硒的回收率在９６－１０１％，过柱溶液中铜的浓度低于０．０１μｇ／ｍＬ。方法检出限为５×１０＾－５％，分析紫铜中４．４×１０＾－４％的硒，相对标准偏差为３％。     

用石墨炉原子吸收法测定水质中微量砷,硒的探讨

采用石墨炉原子吸收法测定水中微量砷，硒，经大量实验条件摸索，选择不同仪器分析工作条件，找出了最佳升温程序条件，特别是原子化时气流控制，使分析方法的检出限降低为：Ａｓ０．６μｇ／Ｌ，Ｓｅ０．５μｇ／Ｌ。线性范围；Ａｓ０．０００－０．１２０ｍｇ／Ｌ，Ｓｅ０．０００－０．０２４ｍｇ／Ｌ；精密度，相对标准偏差分别为：Ａｓ１．２６％，３．６７％，Ｓｅ２．５６％，４．５７％，回收率为：Ａｓ９８．０％－１１０．     

钯—抗坏血酸基体改进剂石墨炉原子吸收光谱法测定食品中的痕量硒

本文用塞曼效应石墨炉原子吸收法测定食品中的硒，研究了各种基体改进剂对硒信号的改进效应，找出最佳的改进剂钯－抗坏血酸，使硒的灰化和原子化都能达到较高温度，在提高灵敏度，降低干扰方面也取得较好的效果。本方法操作简单、快速、灵敏度高，能有效地测定食品中的痕量硒。方法的回收率在９５．６％－１０４．０％之间，其相对标准偏差为３．０％，检出限为４．４８５ｎｇ／ｍＬ。     

不同产地黄芪中微量硒的分析比较

采用催化光度法测定了不同产地黄芪中微量硒的含量。平均回收率９６．８％，变异系数２．３４％。     

氢化物发生石墨炉原子吸收光谱法直接测定高温镍基合金中的硒

在６ｍｏｌ／Ｌ盐酸介质和０．１％ＫＢＨ４条件下，不但能有效地发生硒的氢化物，而且５ｍｇ／ｍｌＮｉ和３ｍｇ／ｍｌＦｅ都不干扰硒的测定。利用涂钯石墨；管作为氢化物的原子化器，直接测定了高温镍基合金中的硒，特征质量为４０ｐｇ，相对标准偏差在６．１％以内，回收率在９７％－１１０％之间。     

紫外分光光度法测定12种药材中的微量硒

采用紫外分光光度法，以邻苯二胺为显色剂测定了12种药材中微量硒的含量。本法回收率为98．95％，变异系数1．34％．     

硒代二半胱氨酸对白血病细胞系的诱导分化研究

硒抑制体外白血病细胞的生长和增殖．并能诱导部分白血病细胞分化成熟。但其药理作用因硒制剂的不同而异．硒代二半胱氨酸抑制V937和K562血病细胞的生长和增殖，半数抑制浓度为3．0μmol／L，经30μmol／L硒代二半胱氨酸作用3天后，U937胞吞噬率以5％上升至14％，K562细胞内血红蛋白含量由0．20增至0．40μg／10^6细胞，说明硒代二半胱氨酸能诱导部分白血病细胞分化成熟。     

氢化物发生电感耦合等离子体原子发射光谱法同时测定水和生物样品中…

研究了一种小型同心氢化物发生配置一个气液分离器后与多道ＩＣＰ－ＡＥＳ联用，同时测定水和生物样品中砷、铋、锑、硒的方法。检出限为砷０．４μｇ／Ｌ，铋０．５μｇ／Ｌ，锑１．４μｇ／Ｌ，硒０．５μｇ／Ｌ，相对标准偏差为砷２．７％，铋１．５％，锑２．７％，硒１．９％。用本法测定美国和国家标准物质中的氢化元素，结果满意。     

氢化物—无色散原子荧光法测定螺旋藻胶囊中的微量硒

研究了氢化物原子荧光法测定螺旋藻胶囊中的微量硒，系统地考察了消解体系；确定了最佳测定条件，共存元素的影响及干扰的消除，硒的检出限为１．３×１０＾－３ｍｇ／Ｌ，线性范围为０－０．２５ｍｇ／Ｌ，回收率在９７．５％－１０２．３％之间，ＲＳＤ小于５％。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.