新显色剂二溴对甲基偶氮甲磺光度法测定钡的研究和应用

研究了新显色剂二溴对甲基偶氮甲磺光度测定微量钡的方法在０．２４ｍｏｌ．Ｌ＾－１Ｈ３ＰＯ４介质中试剂与钡形成蓝色配合笺，在 ６３２ｎｍ处具有最大吸光度，摩尔吸系数为７．１３×１０＾４Ｌ．ｍｏｌ＾－１．Ｃｍ＾－１。     

胶束增敏紫外吸光光度法测定甲睾酮

用紫外吸光光度法对硫酸介质中甲睾酮与溴化十六烷基三甲铵形成的胶束配合物的性能和条件进行了系统研究，提出了利用胶束的增增敏稳作用测定甲睾酮的紫外吸收光光度新方法，本法的灵敏度高，表观摩尔吸光系数ε２４４为２．２８×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，检出限为２．４×１０＾－７ｍｏｌ．Ｌ＾－１，用于片剂中甲睾酮含量的测定，与药典对照结果吻合。     

钪—镧—对氟偶氮氯膦体系共显色效应的研究及应用

本文研究了钪－镧－对氟偶氮氯膦体系共显色效应的光度特性及测定钪的最佳条件，建立了光度法测定痕量钪的新方法。该法的表观摩尔吸光系数为８．５７×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，Ｓｃ（Ⅲ）浓度在０．０－５．０μｇ／２５ｍｌ范围符合比尔定律。将本法用于镁基，铁基合成试样中痕量钪的测定，结果满意。     

氟化钙增敏石墨炉原子吸收法测定人发和血清样品中痕量钼的研究

石墨炉原子吸收法测定生物样品中痕量钼时，用氟化钙作基体改进剂，可使钼的原子吸光度提高５．７倍，其特征量原来的４．２× １０＾－１１ｇ／１％吸收降低到５．１×１０＾－１２ｇ／１％吸收，测定下限为０．５５ｎｇ·ｍＬ＾－１，线性范围为０～１０００ｎｇ· ｍＬ＾－１． 对人发和牛血清标样中痕量钼测定。结果满意。     

新显色剂5—（4—氯—2—羟基苯偶氮）罗丹宁与银（Ⅰ）显色反应的研究和应用

本报道了新显色剂５－（４＇－氯－２＇－羟基苯偶氮）罗丹宁的合成及其光度法测定银的条件，在ｐＨ＝５．０的缓冲介质中，该显色剂与银形成黄色络合物，其络合比为Ａｇ（Ｉ）：Ｒ＝１：２，摩尔吸光系数为１．１×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，用拟定的方法测定阳极泥，废定影液中银的含量，结果满意。     

鸟嘌呤—铜配合物在汞电极表面上的电吸附性的研究

在０．０２ｍｏｌ／Ｌ ＮａＨＣＯ３－０．０５ｍｏｌ／Ｌａ２ＳＯ４介质中、用极谱法和伏安法研究表明,铜－乌嘌呤配合物在汞电极表面上的吸附服从Ｌａｎｇｍｕｉｒ吸附,测得其饱和吸附量Γｍ＝１．１×１０＾－１０ｍｏｌ／ｃｍ＾２,吸附系数β＝４．７×１０＾４,吸咐自由能△Ｇ°＝－３６．６ｋＪ／ｍｏｌ。在８×１０＾－６ｍｏｌ／Ｌ Ｃｕ＾２＋离子存在下,可用示差脉冲阴极吸附溶出法测定８×１０＾－１０～１×１０＾     

6—Br—BTAPC三波长分光光度法同时测定痕量钼和钨的研究

基于Ｍｏ（Ⅵ）和Ｗ（Ⅵ）与新显色剂４－（６－溴－２－苯并噻唑偶氮）邻苯二酚（６－Ｂｒ－ＢＴＡＰＣ）和二苯胍（ＤＰＧ）在ｐＨ４．０时形成稳定的１：２：２电中性紫红色三元离子缔合物的灵敏显色反应，用三波长法同时萃取分光光度法测定了体系中共存的钼和钨，两配合物氯仿萃取液的λｍａｘ分别为５５９和５３９ｎｍ，表观摩尔吸光系数分别为８．６３×１０＾４和６．５３×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，比耳定律的     

7—（对甲酰基苯偶氮）—8—羟基喹啉—5—磺酸的合成及其双波长分光光度…

７－（对甲酰基苯偶氮）－８－羟基喹啉－５－磺酸是一新显色剂，该试剂在微碱性介质中（ｐＨ＝７．５）与镓形成黄色络合物，络合物λｍａｘ＝３９２ｎｍ，摩尔吸光系数ε３９２＝２．２４×１０＾４Ｌ．ｍｃｌ＾－１．ｃｍ＾－１，同时在５００ｎｍ呈现负峰，用双峰双波长法测定镓ε３９２－５００＝６．８９×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，灵敏度是单波长法的三倍多，线性范围０～２．０×１０＾－６ｍｏｌ／Ｌ。用拟定     

酚—次氯酸盐直接显色法测定血氨

报道了酚－次氯酸盐直接显色法测定血氨。结果表明，显色反应在ｐＨ１１．０￣１１．６范围内吸光度大、稳定且干扰小。有色化合物最大吸收波长位于６３５ｎｍ，表观魔鬼洋吸光系数为１．８３×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，血氮浓度在０￣１２００μｍｏｌ／Ｌ范围内符合比耳定律，检测下限为４．８μｍｏｌ／Ｌ。采用两种碱浓度不同的次氯酸盐溶液分别测定标准和血液样品，保持了显色溶液酸度一致性，因而提高了血氨测定     

锌柱还原分光光度法测定微量砷

对锌柱还原砷及其测定进行了研究，胂化氢以Ａｇ＾＋－ＰＶＡ－ＥｔＯＨ－Ｈ２Ｏ为吸收液，在λｍａｘ４００ｎｍ处进行吸光度测定，砷在０－１．８ｍｇ／Ｌ范围内与吸光度呈良好线性关系，其ε＝８．７×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。检出限为２４μｇ／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.     

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.