Ti（Ⅳ）－F~－－邻硝基苯基荧光酮－氯化十六烷基吡啶四元体系显色反应的研究

本文较详细研究了在Ｈ＿２ＳＯ＿４介质中，Ｔｉ（Ⅳ）－Ｆ￣－－ｏ－ＮＰＦ－ＣＰＣ体系水相光度法测定痕量钛的新方法。四元体系的最大吸收峰在５６５ｎｍ处，表观摩尔吸光系数为２．１×１０￣５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），Ｓａｎｄｅｌｌ灵敏度为２．２８×１０￣（－４）μｇＴｉ／ｃｍ￣２。钛含量在０～４μｇ／２５ｍＬ范围内遵守比尔定律。方法用于土壤、粮食、牧草、蔬菜和中草药中钛的测定，结果满意。     

钛－安替比林偶氮连苯三酚－抗坏血酸－苄基十四烷基二甲基氯化铵四元络合体系的分光光度法研究

本文利用自制的安替比林偶氮连苯三酚（ＡｎＡＰ）研究了Ｔｉ－ＡｎＡＰ－抗坏血酸（Ｖｃ）－苄基十四烷基二甲基氯化铵（Ｚｅｐｈ）四元络合体系。结果表明，四元络合体系在ｐＨ５．０～６．５范围内对测钛具有较高灵敏度，最大吸收波长４７５ｎｍ处的表现摩尔吸光系数为６．０３×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）。铁量在０～１２μｇ／２５ｍＬ范围内服从比尔定律。加入乙酰丙酮等掩蔽剂后，此体系可用于某些矿石、土壤等样品中微量钛的测定。     

阴离子表面活性剂－溴化十二烷基二甲基苄基铵－溴百里酚蓝显色反应的分光光度法研究

本文研究了溴化十二烷基二甲基苄基铵－溴百里酚蓝与阴离子表面活性剂显色反应的适宜条件。结果表明，在ｐＨ７．４～８．２范围内阴离子表面活性剂与题示试剂形成１：２：１的绿色离子缔合物，其最大吸收峰位于６１４ｎｍ处。表现摩尔吸光系数分别为：＝３．９９×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）；＝３．７０×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）；＝１．７１×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）。ＳＤＢＳ在０～１９５μｇ／１０ｍＬ，ＳＤＳ在０～１５８μｇ／１０ｍＬ，ＳＬＳ在０～６０μｇ／１０ｍＬ范围内遵守比耳定律。该法用于河水和生活废水中阴离子表面活性剂测定，结果满意。     

2－（3，5－二氯－2－吡啶偶氮）－5－二甲氨基苯胺与铂（Ⅳ）显色反应的研究

研究了２－（３，５－二氯－２－吡啶偶氮）－５－二甲氨基苯胺与铂（Ⅳ）的显色反应，在ｐＨ３．５～６．０醋酸－醋酸钠介质中，沸水浴加热２５ｍｉｎ，试剂与铂（Ⅳ）形成１：４的紫色配合物，再提高酸度至２．９～４．０ｍｏｌ／Ｌ盐酸溶液，其最大吸收峰红移至６３０ｎｍ，灵敏度显著提高，表现摩尔吸光系数ε＿（６００）＝７．０×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），铂含量在０～３２μｇ／２５ｍＬ范围内符合比耳定律。大多数常见金属离子不干扰测定，所拟方法操作简便，用于催化剂中微量铂的测定，结果满意     

催化光度法测定痕量α，α′－联吡啶

基于α，α′－联吡啶对Ｈ＿２Ｏ＿２氧化靛红的褪色反应的催化作用，本文建立了测定α，α′－联吡啶的新催化光度法，灵敏度为２．２５×１０￣（－９）ｍｏｌ·Ｌ￣（－１），测定范围为０～４×１０￣（－８）ｍｏｌ／２５ｍＬ。     

对乙酰基偶氮氯膦与钛显色反应的研究及镁砂和铝矾土中钒的测定

本研究了对乙酰基偶氮氯膦与钛的显色反应，结果表明，在ｐＨ３．６到０．５ｍｏｌ／Ｌ的盐酸酸度范围内，钛与试剂形成组成比为１：２的蓝色配合物，最大吸收波长为６８５ｎｍ，表观摩尔吸光系数为１．７５×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，钛浓度在０～２５μｇ／２５ｍＬ范围内符合比耳定律。多数金属元素不干扰测定，在掩蔽剂存在下，可测定镁砂和铝矾土中二氧化钛。     

甲基橙－溴化十六烷基三甲胺三元络合物分光光度法测定微量铜（Ⅱ）

本文介绍了甲基橙与铜（Ⅱ）在ｐＨ３．８时与溴化十六烷基三甲胺形成三元胶束络合物增溶于聚乙烯醇体系中，其表观摩尔吸光系数ε＿（５８０）为２．９５×１０￣６Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），铜（Ⅱ）浓度在０．１～０．６μｇ／２５ｍＬ范围内与吸光度成线性关系。用此法分析人发中铜含量，结果满意。     

用钼酸盐和罗丹明B光度法测定铂

本文研究了在聚乙烯醇（ＰＶＡ）存在下用钼酸盐和罗丹明Ｂ（ＲＢ）光度法测定铂，铂（Ⅳ）与相酸铵和罗丹明Ｂ形成离子缔合物，它的最大吸收波长位于５７０ｎｍ处；摩尔吸光系数６值为６．８３×１０￣５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），铂量在０～３．５μｇ／２５ｍＬ范围内服从比耳定律，缔合物至少稳定１月。报告了４１种共存离子的影响，除生成杂多酸元素和Ａｕ（Ⅲ）、Ｏｓ（Ⅷ）、Ｒｕ（Ⅲ）外，大多数元素不干扰。测定铂（Ⅳ）的适宜条件为［ＨＣｌＯ＿４］＝０．９３ｍｏｌ／Ｌ，［ＲＢ］＝４．２×１０￣（－５）ｍｏｌ／Ｌ，ＰＶＡ０．８ｇ／Ｌ，本法已用于催化剂和某些铂矿中铂的测定，结果满意。缔合物的摩尔比为Ｐｔ（Ⅳ）：ＲＢ＝１：２，初步探讨了反应机理。     

Cu（Ⅰ）的高灵敏度显色反应的研究Ⅱ．及其在绿茶测定中的应用

本文研究了在硫酸介质中，Ｃｕ（Ⅰ）－ＳＣＮ￣－罗丹明Ｂ体系当有明胶和聚乙醇辛基苯基醚存在时的显色反应。该反应的λｍａｘ＝５９５ｎｍ，ε＝２．０×１０５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），铜在０～５．００μｇ／２５ｍＬ范围内具有良好的线性关系。据此拟定的分析方法，用于测定绿茶中的痕量铜，选择性好，灵敏度高，结果满意。     

7－（4，5－二甲基－2－噻唑偶氮）－8－羟基喹啉与锌显色反应的研究和应用

探讨题示试剂（ＤＭＴＡＱ）与锌离子的显色反应条件，当ｐＨ为５．５，在ＴｒｉｔｏｎＸ－１００存在下，ＤＭＴＡＱ与锌离子形成红色配合物，最大吸收峰位于５４５ｎｍ，表观摩尔吸光系数９．４×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），锌量在０～２５μｇ／５０ｍＬ范围内符合比尔定律。该法可用于测定人发中的微量锌。     

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.     

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.     

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.