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。     

无机还原剂与光泽精化学发光反应的研究：Ⅲ.钒（Ⅱ）—光泽精体系的化…

本采用装有Ｊｏｎｅｓ柱的流动注射系统，研究了钒（Ⅱ）－光泽精体系的化学发光反应。在此基础上建立了痕量钒测定的新方法。方法的检出限３×１０＾－１０ｇ·ｍＬ＾－１；对于１．０×１０＾－７ｇ·ｍＬ＾－１钒标准溶液测定的相对标准偏差为２％（ｎ＝１１）；线性范围１．０×１０＾－９￣９．０×１０＾－５ｇ·ｍＬ＾－１，相关系数大于０．９９８０。该方法已用于水样中痕量钒的测定。对于反应机理，本也进行了探讨。     

偶合反应化学发光法测定痕量银的研究——K4Fe（CN）6—Luminol体系

将Ａｇ（Ｉ）催化Ｋ４Ｆｅ（ＣＮ）６的水合反应与Ｌｕｍｉｎｏｌ同Ｃｕ（ＣＮ）＾２－４的化学发光反应相偶合，建立起一种新的灵敏测定痕量银的化学发光分析法，在所研究的优化条件下，该法测定银的选择性较好，检测限达到４．０×１０＾－１３ｇ／ｍＬＡｇ线性浓度范围为１．０×１０＾－１２～１．０×１０＾－６ｇ／ｍＬＡｇ对４×１０＾－１１ｇ／ｍＬＡｇ（Ｉ）溶液连续１１次测定的ＲＳＤ≤３．５％，用于环境水和岩矿中银的     

氯酸钾－二甲基黄－钒（Ⅴ）体系催化光度法测定痕量钒

本文研究了氯酸钾－二甲基黄－钒（Ⅴ）体系催化光度法测定痕量钒的条件及应用。钒含量在０～６０ｎｇ／１０ｍＬ范围内与ｌｇ（Ａ＿０／Ａ）有良好的线性关系，检出限１．０×１０￣（－１１）ｇ／ｍＬ。方法简便快速，应用于水及食品中痕量钒测定，结果满意。     

测定钴的化学发光新体系

研究了新吖啶衍生物９，１０－二甲基吖啶氟磺酸盐的化学发光特性。建立了测定Ｃｏ６２＋的化学发光新体系。方法线性范围为１．０×１０＾－１０－１．０×１０＾－７ｇ／ｍＬ；检测限为５．０×１０＾－１１ｇ／ｍＬＣｏ＾２＋。测定５．０×１０＾－９ｇ／ｍＬＣｏ６２＋的相对标准偏差为６．０％。方法选择性好，用于自来水，江水，池塘水中痕量钴的测定，结果令人满意。     

偶合反应化学发光法测定痕量银的研究

本将Ａｇ（Ⅰ）催化Ｓ２Ｏ＾２－８氧化Ｍｎ（Ⅱ）生成ＭｎＯ＾－４的催化反应与ＬｕｍｉｎｏｌＭｎＯ＾－４－ＯＨ＾－的化学发光反应相偶合，建立起一种新的灵敏测定痕量银的化学发光分析法，在所研究的优化条件下，该法测定银的选择性较好，检测限达到３．２×１０＾－１２ｇ／ｍＬＡｇ线性浓度范围为１．０×１０＾－１１－１．０×１０＾－５ｇ／ｍＬＡｇ，用于水样分析，结果较为满意。     

流动注射化学发光法测定甲氨蝶呤

研究了甲醛增强高锰酸钾与甲氨蝶呤的化学发光反应，由此建立了一种测定甲氨蝶呤的流动性注射化学发光分析法，方法的检出限为３．４×１０＾－９ｇ／ｍＬ，相对标准偏差为１．１％（２．０×１０＾－６ｇ／ｍＬ甲氨蝶呤，ｎ＝１１）线性范围为１．０×１０＾－８～１．０×１０＾－５ｇ／ｍＬ。该法已用于甲氨蝶呤针剂及片剂中甲氨蝶呤含量的测定。     

高磺酸钾—罗丹明6G催化荧光法测定超痕量钌

研究了在盐酸介质中,钌催化高碘酸钾氧化罗丹明６Ｇ的反应及动力学条件,建立了高灵敏测定超痕量钌的新方法。线性范围为０．２～１．０ｎｇ／２５ｍＬ,检出限为６．５×１０＾－１２ｇ／ｍＬ。方法已用于合成样中钌的测定。     

催化反应吸光光度法测定痕量银

研究了Ａｇ对亚铁氰化钾与邻菲罗啉显色反应的催化研究，建立了痕量银的催化吸光光度法。灵敏度为１．０×１０＾－３μｇ．ｍｌ＾－１，线性范围为０－０．４μｇ／２５ｍＬ。用于水样中痕量银的测定，结果满意。     

无机还原剂与光泽精化学发光反应的研究Ⅲ．钒（Ⅱ）－光泽精体系的化学发光反应

本文采用装有Ｊｏｎｅｓ柱的流动注射系统，研究了钒（Ⅱ）－光泽精体系的化学发光反应。在此基础上建立了痕量钒测定的新方法。方法的检出限３×１０￣（－１０）ｇ·ｍＬ￣（－１）；对于１．０×１０￣（－７）ｇ·ｍＬ￣（－１）钒标准溶液测定的相对标准偏差为２％（ｎ＝１１）；线性范围１．０×１０￣（－９）～９．０×１０￣（－５）ｇ·ｍＬ￣（－１），相关系数大于０．９９８０。该方法已用于水样中痕量钒的测定。对于反应机理，本文也进行了探讨。     

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.     

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.     

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.     

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.     

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.     

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.