钙－芦丁极谱络合吸附波的研究

在０．０１ｍｏｌ／ＬＫＯＨ底液中（ｐＨ＝１１．７），用单扫示波极谱法可获得钙－芦丁络合吸附波，检出限为８．０×１０－７ｍｏｌ／Ｌ．测得电活性络合物组成为Ｃａ（Ⅱ）∶Ｒｔ＝１∶２，条件稳定常数为β＝４．８×１０１０．电极表面反应速率常数为ｋｓ＝１．２７ｓ－１．     

金属离子与卟啉的嵌入反应动力学研究──Ⅶ．一元酸根催化Cu（Ⅱ）与溴化间－四（N－乙酸甲酯基－3－吡啶基）卟啉的配位反应

研究了在３５±０．１℃、离子强度０．５ｍｏｌ／Ｌ（ＫＣｌ）条件下，甲酸根、乙酸根、丙酸根和丁酸根分别催化Ｃｕ（Ⅱ）离子与四溴化间－四（Ｎ－乙酸甲酯基－３－吡啶基）卟啉（Ｈ２ＴＢ－Ｎ－ＡＣＭＳｐｙＰＢｒ４）的反应动力学及其机理，该类反应对卟啉和Ｃｕ（Ⅱ）离子均为一级反应，反应动力学方程为：ｄ［Ｃｕｐ４＋］／ｄｔ＝ｋ｛（１．０＋ｂ［Ａ－］）／（１．０＋Ｋ３，４·［Ｈ＋］２）｝［Ｃｕ２＋］［ｐ］Ｔ，在甲酸－甲酸根缓冲体系中，ｋ＝２．９８ｍｏｌ－１ｄｍ３·ｓｅｃ－１，ｂ＝１５４×１０２ｍｏｌ－２，ｄｍ６·ｓｅｃ－１，Ｋ３，４＝６．９２８×１０３；在乙酸－乙酸根缓冲体系中，ｋ＝３．４２ｍｏｌ－１·ｄｍ３·ｓｅｃ－１，ｂ＝２．２９×１０３ｍｏｌ－２·ｄｍ６·ｓｅｃ－１，Ｋ３，４＝６．９２８×１０３；在丙酸－丙酸根缓冲体系中，ｋ＝３．００ｍｏｌ－１·ｄｍ３·ｓｅｃ－１，ｂ＝５．９０×１０２ｍｏｌ－２·ｄｍ６·ｓｅｃ－１，Ｋ３，４＝７．００７×１０３；在丁酸－丁酸根缓冲体系中，ｋ＝３．１４ｍｏｌ－１·ｄｍ３·ｓｅｃ－１，ｂ＝３．７５×１０２ｍｏｌ－２·ｄｍ６·ｓｅｃ－１，Ｋ３，４＝６．９２１×１０３；讨论了有机酸根的碱性与     

碘酸钾存在下极谱催化波法测定陈皮甙

基于陈皮甙在ＫＩＯ３存在下产生的极谱催化波，拟定了测定陈皮甙的新方法。在 ０．５５ ｍｏｌ／Ｌ ＨＡｃ－０．０１ｍｏｌ／Ｌ　ＮａＡｃ（ｐＨ ４．００±０．０５）－１．０×１０～（－３）ｍｏｌ／Ｌ ＫＩＯ３缓冲溶液中，陈皮甙催化波的峰电位为－１．３５ Ｖ（ｖｓ，ＳＣＥ），它的一阶导数峰峰电流与陈皮甙浓度在２．６ × １０～（－７）～２．６ × １０～（－６）ｍｏｌ／Ｌ范围内呈线性关系（ｒ＝０．９９７０，ｎ＝６）。本方法比现有的电化学方法灵敏度高一个数量级。可用于直接测定中草药贯众水提液中陈皮甙含量。     

三乙醇胺活化钴（Ⅱ）催化过硼酸钠氧化荔枝红色素褪色光度法测定痕量钴

基于三乙醇胺活化钴（Ⅱ）催化过硼酸钠氧化荔枝红色素的褪色反应，提出测定痕量钻的高灵敏的催化光度法。其摩尔吸光系数ε５００＝１．８×１０７Ｌ·ｍｏｌ－１·ｃｍ－１；线性范围为０～０．４μｇ／Ｌ；工作曲线的回归方程为；相关系数ｒ＝０．９９９８；检测限１．０×１０－１３ｇ／ｍＬ。该褪色反应的表观活化能 Ｅ＝４２．１２ ｋＪ·ｍｏｌ－１，速率常数 ｋ＝１，６×１０－３·ｓ－１。此法用于血清、尿液等样品中钻的测定，结果满意。     

哌仑西平的单扫描示波极谱法测定

本报道一种测定哌仑西平的单扫描示波极谱法，在０．１ｍｏｌ／ＬＮＨ４Ｃｌ－ＮＨ３．Ｈ２Ｏ（ｐＨ８．０±０．１）缓冲液中，哌仑西平有一极谱还原波，其峰电位为－１．５１Ｖ（ｖｓ．ＳＣＥ），其一阶导数峰高与哌仑西闰浓度在６．６×１０＾－７－４．６×１０＾－６ｍｏｌ／Ｌ（ｒ＝０．９９８１）和６．６×１０＾－６－１．６×１０＾－５ｍｏｌ／Ｌ（ｒ＝０．９９９１）范围内有线性关系，检测限为３．４×１０－７ｍｏｌ     

安力农的极谱测定及其电化学行为

在ｐＨ５．６，０．１５ｍｏｌ／Ｌ磷酸盐缓冲溶液（ＰＢＳ）中，得到了安力农的灵敏极谱吸附波，波的二阶导波高在２×１０＾－８～８×１０＾－６ｍｏｌ／Ｌ范围内与安力农的浓度成直线关系，检测下限为１×１０＾－８ｍｏｌ／Ｌ，测定出电极过程的电子传递系数ａ＝０．４３，表面电极反尖速率常数ｋｓ＝３．３ｓ＾－１，安力农在汞电极上的吸附遵从Ｌａｎｇｍｕｉｒ等温式，测得其吸附系数β＝８．１×１０＾５。     

[Fe(CN)_6]~(4-)还原trans-[Co(en)_2(ImH_)2]~(3+)的电子转移反应动力学机理

在不同的温度下，考察了六氰合铁（Ⅱ）配阴离子［Ｆｅ（ＣＮ）６］４－还原ｔｒａｎｓ－［Ｃｏ（ｅｎ）２（ＩｍＨ）２］３＋的反应动力学。结果表明，反应遵循Ｈ．Ｔａｕｂｅ所提出的外配位界电子传递机理。在２５℃，Ｉ＝０．５ｍｏｌ·Ｌ－１，ｔｒａｎｓ－［Ｃｏ（ｅｎ）２（ＩｍＨ）２］３＋／［Ｆｅ（ＣＮ）６］４－反应体系的前驱配合物离子对形成常数为Ｑ１ｐ＝９８．９ｍｏｌ－１·Ｌ，电子转换速率常数为Ｋｅｔ＝１．３×１０－４ｓ－１，电子转移过程活化焓ΔＨ≠ｅｔ和活化熵ΔＳ≠ｅｔ分别为１４１．２ｋＪ·ｍｏｌ－１、５７３．５Ｊ·ｍｏｌ－１·Ｋ－１。     

维生素K3亚硫酸氢钠的电化学研究

维生素Ｋ３亚硫酸氢钠在０．１ｍｏｌ／ＬＮａＣｌ＋０．０４ｍｏｌ／ＬＨＣｌ，ｐＨ＝１．８０底液中，于示波极谱仪上有一良好的二阶导数波，Ｅ″Ｐ＝－０．７４±０．０１Ｖ（ＳＣＥ），峰高与浓度在５×１０－９～１×１０－６ｍｏｌ／Ｌ以及１×１０－６～１×１０－５ｍｏｌ／Ｌ分段成线性关系，检测下限为１×１０－９ｍｏｌ／Ｌ，用于针剂含量的测定，结果良好。实验证明，当ｐＨ小于３．５９时，维生素Ｋ３亚硫酸氢钠逐渐转变为维生素Ｋ３亚硫酸，出现三个极谱峰，其中用于分析测定的峰为维生素Ｋ３亚硫酸１号位羰基的还原峰，其电极过程为扩散控制的可逆的双电子过程。     

含有吸附络合物溶液的倒数示波计时电位法的应用

Ｐｂ（Ⅱ）在０．２％乙二胺－５×１０＾－３ｍｏｌ·Ｌ＾－１ＨＯｘ－０．３ｍｏｌ·Ｌ＾－１ＫＯＨ溶液中，有良好的全数示波图，其峰电位Ｅｐ＝－１．０５（ｖｓ．ＳＣＥ），峰高与Ｐｂ＾２＋溶度在４．０×１０＾－７～２．０×１０＾－５ｍｏｌ·Ｌ＾－１内成正比，检测下限可达２．０×１０＾－７ｍｏｌ·Ｌ＾－１。本实验采用倒数示波计时电位法对铝合金“Ａ”中铅进行了测定，并直接通过示波图，对络合物的吸附属于性进行了     

Mo（Ⅵ）－PAN与Mo（Ⅵ）－PAR体系的极谱性质对比研究

本文比较了Ｍｏ（Ⅵ）－１－（２－吡啶基偶氮）－２－萘酚（ＰＡＮ）与Ｍｏ（Ⅵ）－４（２－吡啶基偶氮）间苯二酚（ＰＡＲ）的极谱性质，讨论它们在作为吸附波试剂时的优缺点，以求得在选择络合剂时的感性和理性认识．本文还报道了Ｍｏ（Ⅵ）－ＰＡＮ－ＫＢｒＯ３吸附催化波体系，最佳实验条件，０．１ｍｏｌ／ＬＨＡｃ－－ＮａＡｃ，ｐＨ＝４．６，０．０１ｍｏｌ／ＬＫＢｒＯ３，２．５×１０－５ｍｏｌ／ＬＰＡＮ．峰电位为－０．７１Ｖ（ｖｓ．ＳＣＥ），检出限１×１０－９ｍｏｌ／Ｌ，线性范围０～６×１０－７ｍｏｌ／Ｌ     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.     

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.