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     

线性扫描示波极谱法测定抗癌药物紫杉醇

抗癌药物紫杉醇在０．２ｍｏｌ／Ｌ ＮＨ３－ＮＨ３－ＮＨ４Ｃｌ中,采用单扫示波极说法进行测定,形成一良好的还原峰,峰电位Ｅｐ＝－１．４５Ｖ（ｖｓ．ＳＣＥ）。峰电流与紫杉醇的浓度在１．０×１０＾－７￣８．０×１０＾－６ｍｏｌ／ｌ之间呈线性关系;检测限为５．０×１０＾－８ｍｏｌ／Ｌ,并将此方法应用于样品测定。用线性扫描和循环伏安法研究体系的性质,结果表明,紫杉醇的电极过程属于具有吸附性的准可逆过程。     

溶出伏安法测定水中痕量钴

在０．０１ｍｏｌ／ＬＮＨ．Ｈ２Ｏ－ＮＨ４Ｃｌ和３．０×１０＾－５ｍｏｌ／Ｌ安息香缩氨基硫脲体系中，钴产生一灵敏的还原波，其峰电位是－０．９４Ｖ（ｖｓ．ＳＣＥ），峰电流与钴的浓度在２．０×１０－８－１．０×１０＾－６ｍｏｌ／Ｌ范围内成直线关系，检测限为５．０×１０＾－９ｍｏｌ／Ｌ，该法测定水中痕量钴结果令人满意。     

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。     

硅钼杂多阴离子薄膜修饰电极线性扫描伏安法测定黑液中要溶性硅

本报导了以玻碳电极为基体的１∶１２硅钼杂多阴离子薄膜化学修，铈电极的制备及其电化学特性。并应用于导数伏安法测定。在４．０×１０＾－３ｍｏｌ／Ｌ９ＮＨ４）６Ｍｏ７Ｏ２４－６６．８×１０＾－２ｍｏｌ／ＬＮａ３Ｃｉｔ－０．４８ｍｏｌ／Ｌ ＮＨＯ３体系中，硅浓度在８．３×１０＾－７～１．７×１０＾－３ｍｏｌ／Ｌ。对可溶性硅（以ＳｉＯ２计）为２４５．０５ｍｇ／Ｌ的黑液，稀释１０倍后，取２．００ｍＬ平行测定     

多菌灵在玻碳电极上的伏安行为及其应用

应用循环伏安法、微分脉冲伏安法对多菌灵在破碳电极上的电化学行为及其测定进行了研究。在ｐＨ＝９．０的２ｍｏｌ／Ｌ ＮＨ３－ＮＨ４Ｃｌ底液中，对其进行循环伏安扫描，发现于０．６１Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）产生一灵敏的氧化峰。微分脉冲伏安法殉菌灵的检测限为４×１０＾－８ｍｏｌ／Ｌ。多菌灵的浓度在５．０×１０＾－７￣１．０×１０＾－５ｍｏｌ／Ｌ间与微分脉冲伏安峰电流呈线性关系（ｒ＝０．９９４２）。对于１×     

托美汀的吸附伏安法研究

在０．２ｍｏｌ／Ｌ ＮＨ３－ＮＨ４Ｃｌ底液中，托美汀在悬汞电极上有一灵敏的还原峰。峰电位为Ｅｐｃ＝－１．４８Ｖ，该峰具有明显的吸附性，峰电流ｉｐｃ与ＴＯＬ浓度在４．０×１０＾－９－７．０×１０＾－７ｍｏｌ／Ｌ范围内呈线性关系；检出限为５．０×１０＾－１０ｍｏｌ／ｌ，用该法测定了片剂ＴＯＬ的含量，结果良好。     

锑—铜—茜素络合剂体系极谱行为的研究

在１．０ｍｏｌ／Ｌ甲酸－甲酸钠－０．０３ｍｏｌ／Ｌ邻苯二甲酸氢钾混合底液（ｐＨ３．５）中，锑－茜素络合剂（ＡＬＣ）络合物在单扫示波极谱上于一０．５３Ｖ（ｖｓ．ＳＣＥ）产生一极谱波，加入１．６×１０＾－３ｍｏｌ／ＬＣｕ（Ⅱ）后，灵敏度有较大提高，峰电流与锑浓度在２．０×１０＾－８～３．０×１０＾－６ｍｏｌ／Ｌ范围内呈线性关系，检测限达１．０×１０＾－８ｍｏｌ／Ｌ，研究了电极反应机理，方法应用于铜合金     

铜（Ⅱ）锌（Ⅱ）—氟哌酸体系电化学行为及示波极谱法研究

铜（Ⅱ）和锌（Ⅱ）分别在０．１ｍｏｌ／ＬＫＨ２ＰＯ４－Ｎａ２ＨＰＯ４缓冲溶液（ｐＨ６．５）和０．２５ｍｏｌ／ＬＮＨ４Ｃｌ溶液中，与氟哌酸形成良好的络合吸附波，峰电位分别为－０．２６Ｖ和－１．２８Ｖ（ｖｓ．ＳＣＥ），络合比分别为１：３和１：２，峰电流与铜（Ⅱ）和锌（Ⅱ）的浓度均在４．０×１０＾－７～５．０×１０＾－６ｎｏｌ／Ｌ范围内呈线性关系，检测限分别为７．０×１０＾－８和５．０×１０＾－８ｍｏｌ     

一种基于形成杂多核络合物的荧光增敏效应的研究：Ⅲ.锰（Ⅱ）,钴（…

本研究了Ｍｎ＾２＋和Ｃｏ＾２＋对７－（８－羟基－３，６－二磺基萘偶氮）－８－羟基喹啉－５－磺酸－硼砂反应体系的混合荧光增敏作用。实验条件下，荧光增敏强度满足线性加和关系的范围是：Ｍｎ＾２＋浓度０￣２．９×１０＾－７ｍｏｌ／Ｌ；Ｃｏ＾２＋浓度０￣８．８～１０＾－７ｍｏｌ／Ｌ；总浓度不超过１．０×１０＾－６ｍｏｌ／Ｌ。检出限量为Ｍｎ＾２＋４．５×１０＾－９ｍｏｌ／Ｌ和Ｃｏ＾２＋１．４×１０＾－８ｍｏ     

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.     

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.     

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.     

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.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.