头孢噻肟钠的降解及其产物伏安行为的研究

头孢噻肟钠在ＮａＯＨ溶液中降解后，于０．１ｍｏｌ／ＬＮａＯＨ中得一灵敏的吸附伏安原峰，Ｅｐ＝－０．７８Ｖ（νｓＡｇ／ＡｇＣｌ），ｉｐ与头孢噻肟钠浓度在１．０×１０＾－＾９－１．０×１０＾－＾８，１．０×１０＾－＾８－１．０×１０＾－＾７，１．０×１０＾－＾７－１．０×１０＾－＾６ｍｏｌ／Ｌ范围内呈线性关系，检出限为５．０×１０＾－＾１＾０ｍｏｌ／Ｌ。用多种电化学手段研究其降解产物的伏安行为，测定了     

吲哚乙酸与磷钼黄反应及其极谱分析的研究

在ＮＨ３－ＮＨ４Ｃｌ缓冲溶液中（ｐＨ＝９．５），吲哚乙酸与磷钼黄的还原产物在滴汞电极上于－１．１０Ｖ（ｖｓ．ＳＣＥ）处产生一灵敏的极谱波，该波波高与吲哚乙酸的浓度在１．０×１０－７－５．０×１０－６ｍｏｌ／Ｌ范围内成线性关系，检测下限为５．０×１０－８ｍｏｌ／Ｌ。如在上述还原产物中加入偶氮胭脂红Ｂ、孔雀绿、甲基紫等染料及聚乙烯醇，可使极谱波的灵敏度提高，使吲哚乙酸的浓度在５．０×１０－８－１．０×１０－６ｍｏｌ／Ｌ范围内与波高成线性关系，检测下限降低至１．０×１０－８ｍｏｌ／Ｌ。     

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％。     

硒,砷在水稻体内的相互作用及其自由基机理的研究

以水稻为对象观察了砷（ＮａＡｓＯ２）的毒性作用及硒、砷毒性的相互作用。当培养液中砷（ＮａＡｓＯ２）的浓度约大于０．１×１０－６时，砷会抑制水稻的生长。当硒（Ｎａ２ＳｅＯ３）的浓度范围在０×１０－５～１×１０－６时，硒能拮抗砷的毒性，但硒的浓度大于１×１０－６时，硒会增加体系的毒性。有关作用的机理为自由基机理。     

亚硝酸根－品红－8－羟基喹啉吸附波的研究及痕量亚硝酸根的测定

在醚性介质中，碱性染料品红与亚硝醚粮重氦化，然后在碱性介质中与８－羟基喹啉偶联生成偶氮化合物。该偶氮化合物于电位－０．７０Ｖ（ｖｓ．ＳＣＥ）处有一灵敏的极谱波，波高与亚硝酸根浓度在７×１０￣（－９）～５×１０￣（－６）ｇ／ｍＬ范围内呈线性关系，检测限为５×１０￣（－９）ｇ／ｍＬ。该方法用于人唾液中亚硝醚根的测定，结果满意。     

硫氰酸盐—乙基紫—阿拉伯树胶体体系吸光光度法测定痕量硒

在０．５０－０．５８ｍｏｌ．Ｌ＾－＾１硫酸溶液中，在阿拉伯树胶存在下，Ｓｅ（Ⅳ）与硫氰酸盐，乙基紫形成可溶性离子缔合物在波长６２０ｎｍ处有最大吸收，表观摩尔吸光系数ε６２０为４×１０＾５为４×１０＾５，硒含量在０－４．０μｇ／２５ｍｌ范围内服从比一律。研究了形成离子缔给物的最佳条件和共存离子的影响，方法用于水样和人发样中痕量硒的测定，结果满意。     

铋－2，3，4－三羟基－4′－磺基－偶氮苯配合物吸附波的研究

在０．０６ｍｏｌ／Ｌ柠檬醚钠－０．００３ｍｏｌ／ＬＨＣ１（ｐＨ６．５）介质中，２，３，４－三羟基－４′－磺基－偶氮苯和铋产生灵敏的单扫描极谱导数峰，铋含量在０～６．７×１０￣（－６）ｍｏｌ／Ｌ范围内与波高成线性关系，检测限２．４×１０￣（－８）ｍｏｌ／Ｌ。用提出的方法测定了锡中的铋，并对反应机理进行了研究。     

铋—2,3,4—三羟基—4‘—磺基—偶氮苯配合物吸附波的研究

在０．０６ｍｏｌ／Ｌ柠檬酸钠－０．００３ｍｏｌ／Ｌ ＨＣｌ（ｐＨ６．５）介质中，２，３，４－三羟基－４＇－磺基－偶氮苯和铋产生灵敏的单扫描极谱导数峰，铋含量在０～６．７×１０＾－６ｍｏｌ／Ｌ范围内与波高成线性关系，检测限２．４×１０＾－８ｍｏｌ／Ｌ。用提出的方法测定了锡中的铋，并对反应机理进行了研究。     

新显色剂邻羧基苯基偶氮桑色素褪色光度法测定微量铁的研究

本文研究了新显色剂基苯偶氮桑色素与铁（Ⅲ）在ｐＨ５．６的缓冲溶液中的褪色反应，实验结果表明，利用此褪色反应测定铁（Ⅲ）其灵敏度高，表观摩尔吸光系数达３．１５×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，线性范围０～０．１μｇ／２５ｍＬ，检测限为：１．８×１０＾－１０ｇ／ｍＬ。应用于黑色食品中微量铁的测定，获是了满意的结果。     

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％。     

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.