锰C-抗坏血酸甲醛-化学发光体系的研究

实验观察到锰 氧化抗坏血酸可以产生弱的化学发光 ,甲醛对这一化学发光反应有较强的增敏作用 ,据此建立了测定抗坏血酸的流动注射化学发光分析法。方法的检出限为 2× 1 0 -8mol/L抗坏血酸 ;线性响应范围为 6 .0× 1 0 -8～ 2 .0× 1 0 -5mol/L。对 1 .0× 1 0 -6mol/L的抗坏血酸进行 1 1次测定 ,相对标准偏差为 2 3%。该方法已成功应用于维生素C针剂和片剂中抗坏血酸含量的测定 ,结果与药典方法测得值一致     

Ru(bipy)_3~(2+)-CO_3~(2-)-SO_3~(2-)-KClO_3体系化学发光法测定空气中的二氧化硫

提出了 Ru(bipy) 2 +3 - CO2 -3 - SO2 -3 - KCl O3 体系化学发光法测定溶液中亚硫酸盐的方法。SO2 -3 浓度与化学发光强度在 1 .0× 1 0 - 7～ 1 .0× 1 0 - 4mol/L 范围内成正比 ,检出限为 8.76× 1 0 - 8mol/L,对 1 .0× 1 0 - 4mol/L SO2 - 3 溶液 6次测定的相对标准偏差为 2 .9%。该法用三乙醇胺作为吸收液 ,成功地用于测定空气中二氧化硫的含量 ,结果满意。     

高锰酸钾-甲醛-碘化学发光法测定碘

在酸性条件下 ,高锰酸钾氧化甲醛产生很强的化学发光。当该体系中有碘离子存在时 ,化学发光强度受到一定的抑制 ,据此 ,建立了新的碘离子的化学发光分析方法。该方法对碘离子检出限为 7.87× 1 0 - 7mol/L,线性范围为 2 .44× 1 0 - 6～ 7.87× 1 0 - 3mol/L,用于食品中碘含量的测定 ,结果满意     

L-酪氨酸-高锰酸钾-硫酸化学发光体系研究

在硫酸介质中 ,L -酪氨酸与高锰酸钾反应能产生较强的化学发光 ,据此建立了测定 L -酪氨酸的分析方法。该法线性范围为 4.0× 1 0 - 6 ～ 2 .8× 1 0 - 5mol/L;检出限为 8.8× 1 0 - 7mol/L;对 1 .0× 1 0 - 5mol/L 的 L-酪氨酸进行连续1 0次平行测定 ,相对标准偏差为 2 .7%。该法已应用于测定医用氨基酸注射液中的 L-酪氨酸。     

锰(Ⅳ)-安乃近-甲醛化学发光体系的研究

实验发现锰(Ⅳ)氧化安乃近可以产生弱的化学发光,甲醛对这一化学发光反应有较强的增敏作用。据此建立了测定安乃近的流动注射化学发光分析法。在最优化的条件下,测定安乃近的线性范围为6 0×10-7～1 0×10-5mol/L,检出限为2×10-7mol/L安乃近。对1.0×10-6mol/L安乃近进行11次测定,相对标准偏差为3.4%。该方法已应用于针剂中安乃近的测定,其结果与药典方法测得值一致。     

诺氟沙星的铽敏化化学发光法研究与应用

本文根据 Tb3+能显著增强 Ce ( ) - SO2 - 3- NFLX体系的化学发光 ,建立了流动注射铽敏化化学发光测定诺氟沙星的新方法。本法的线性范围为 9.0× 1 0 - 9～ 1 .0× 1 0 - 6 mol/L,检出限为 4.5× 1 0 - 11mol/L。利用该法测定了诺氟沙星胶囊中诺氟沙星的含量 ,并对血清和尿样进行了回收率测定 ,回收率在 1 0 0 .4%～ 1 0 5 .7% ,结果令人满意。     

流动注射化学发光测定水杨酸

基于在甲醛存在下 ,水杨酸与KMnO4在酸性介质中直接化学发光反应 ,建立了测定水杨酸的流动注射化学发光的方法 ,该法测定水杨酸的线性范围为5 .0× 1 0 -7～ 1 .0× 1 0 -3 mol L ,检出限为 3.0× 1 0 -7mol L ,相对标准偏差为 2 0 %(水杨酸 5 .0× 1 0 -5mol L ,n =1 1 )。该法已应用于脚癣药水中水杨酸的测定。     

流动注射化学发光增强法测定单宁酸

发现单宁酸对Luminol KIO4 Mn2 +碱性体系的化学发光有较强增敏作用 ,据此建立了流动注射化学发光增强法测定单宁酸的新方法。该法简单、快速、线性范围宽 ,测定单宁酸的检出限为 9× 10 -9mol/L ;线性范围为 3× 10 -8～ 5× 10 -6mol/L ,对于 1× 10 -6mol/L单宁酸测定的相对标准偏差 1 5 % (n =11)。应用于五倍子中单宁酸的测定 ,结果满意。     

反向流动注射化学发光法测定二邻苯二甲酰亚胺甲基二磺酸基酞菁锌

在碱性介质中 ,二邻苯二甲酰亚胺甲基二磺酸基酞菁锌 (简写为ZnPcS2 P2 )可增强Luminol H2 O2 CTAB体系的化学发光 ,据此建立了测定ZnPcS2 P2含量的反向流动注射化学发光分析新方法。用该法测定ZnPcS2 P2 ,其范围为 2 .5× 1 0 - 7～ 1 .0× 1 0 - 8mol/L ,检测限为 9× 1 0 - 9mol/L ,对 1 .0× 1 0 - 7mol/L的Zn PcS2 P2 溶液进行 9次平行测定 ,其相对标准偏差为 1 .2 %。本法有一定的选择性 ,与分光光度法相比 ,灵敏度提高了 1～ 2个数量级。     

流动注射化学发光法测定盐酸羟苄唑

基于在碱性条件下盐酸羟苄唑能够与鲁米诺产生化学发光的现象,建立了流动注射化学发光测定盐酸羟苄唑的新方法。盐酸羟苄唑的浓度在8×10-7~1×10-4mol/L范围内与化学发光强度呈良好的线性关系,方法的(3σ)检出限为3×10-7mol/L,对1×10-5mol/L的盐酸羟苄唑连续11次测定的相对标准偏差为1.7%,回收率为96%~103%。已用于滴眼液中盐酸羟苄唑的测定。     

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%.     

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.     

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.     

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.     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.