新—阶导数双峰光谱法解析及应用──测定NO_3~－和NO_2~－

本文通过对ＮＯ３－和ＮＯ２－的一阶导数光谱研究，提出利用它们各自导致光谱峰值的两种解析方法测定相互干扰的两组份含量，由于利用尽可能最大信息量和导数谱的特有功能，使测定ＮＯ３－和ＮＯ２－灵敏度分别为０．００５μｇ／ｍＬ、０．００９μｇ／ｍＬ（峰高－截矩比ｆ校正系数法）及０．００４μｇ／ｍｌ、０．００６μｇ／ｍＬ（双峰ｋ系组合导致法），线性范围皆为０～１．０μｇ／ｍＬ方法用于水样分析，结果令人满意。     

乳化剂OP对锌,镉,铅电位溶出的增敏作用

在０．０１７ｍｏｌ／Ｌ Ｈ２ＳＯ４－ＨＮＯ３混合酸介质中,乳化剂ＯＰ对锌、镉、铅的电位溶出有显著的增敏作用。在电位－１．５０Ｖ下电解富集６０ｓ时,锌、镉、铅的检出限分别为０．１３μｇ／２０ｍＬ,０．０１６μｇ／２０ｍＬ及０．０２０μｇ／２０ｍＬ;线性范围分别为０．０５～０．５０μｇ／２０ｍＬ,０．０５～０．０８μｇ／２０ｍＬ及０．１０～０．８０μｇ／２０ｍＬ,与峰高呈良好的线性关系。此法用于环境水     

催化极谱测定痕量铬的研究

本文研究了含氨介质中铬（Ⅲ，Ⅵ）－α，α－联吡啶－亚硝酸钠体系的电化学行为。建立了测定痕量铬的方法。测定铬的范围为０．００４－０．０２８μｇ／ｍＬ和０．０４－０．２８μｇ／ｍＬ，检测下限为２．０×１０＾－＾３μｇ／ｍＬ，用以测定生物样品中痕量铬，变异系数为９．８％。     

乙基罗丹明B和高碘酸钾反应动力学测定痕量铑

研究了一个动力学测定铑的方法。在氯化钠－磷酸溶液和加热下铑催化乙基罗丹有Ｂ褪色,１ｇ（Ａ０／Ａ）与铑浓度呈线性的范围是０．２－４．０μｇ／２５ｍＬ,检出限为２．２４×１０＾－１０ｇ／ｍＬ,对２．０μｇ铑标准溶液测定１１次的相对标准偏差为２．１３％。     

单柱离子色谱法同时测定磷酸中痕量钠（Ⅰ）和铁（Ⅲ）

以酒石酸－乙二胺为淋洗液的单柱离子色谱法同时测定磷酸中痕量钠（Ⅰ）和铁（Ⅲ）。淋洗液最佳浓度为４．０ｍｍｏｌ．Ｌ￣（－１）、酒石酸／１．０ｍ　ｍｏｌ·Ｌ￣（－１）乙二胺。最低检测限为Ｎａ￣＋０．０５μｇ／ｍＬ、　Ｆｅ３＋　０．４５μｇ／ｍＬ。电导检测灵敏度为２．０μｇ／ｃｍ。线性范围Ｎａ￣＋、Ｆｅ３＋０．２～１．５×１０３μｇ／ｍＬ、２．５～１．０×１０３μｇ／ｍＬ。相对平均偏差Ｎａ￣＋为２．０３％、Ｆｅ３＋为０．８３％。平均回收率Ｎａ￣＋为９８．２６％、Ｆｅ３＋为９７．６２％。本法简便、快速、准确、选择性好。     

单扫描极谱法连续测定人发中的微量元素锌铁锰铜

本提出在０．１５ｍｏｌ／Ｌ乙二胺－７．５×１０＾－３ｍｏｌ／Ｌ三乙醇胺－２．５×１０＾－２ｍｏｌ／Ｌ硫氰酸钾底液中单扫描极谱法测定锌、铁、锰，续加硫酸（０．３ｍｏｌ／Ｌ）测定铜的方法，峰电位分别为－１．４２Ｖ，－１．６３Ｖ，－１．７１Ｖ，－０．４８Ｖ（ｖｓ．ＳＣＥ），线性范围：０．０５～１．４μｇ／ｍＬＭｎ，０．０４～１μｇ／ｍＬＣｕ，最低检出浓度．０３，０．０５，０．０２，０．０４μｇ／ｍＬＭ     

赤霉素的2.5分微分伏安法研究及应用

在０．６５ｍｏｌ／Ｌ硫酸介质中，赤霉素的降解产物－１．０Ｖｖｓ．ＳＣＥ产生一灵敏的２．５次分微分极谱波，探讨了赤霉素降解产物的伏安特性，赤霉素浓度在０．２～８μｇ／ｍＬ范围内与ｅ″值呈良好的线性关系，方法的检出限为０．１μｇ／ｍＬ，已用于试样分析。     

木立芦荟营养成分与功效

对木立芦荟中的蛋白质、超氧化物歧化酶、微量元素、维生素、多糖及水分进行了测定。其结果表明,本立芦荟原汁液中蛋白质含量为０．７４２ｍｇ／ｍＬ、超氧化物歧化酶活力为１０．２４５６ｎ／ｍＬ、维生素Ｂ２含量为０．００１９ｍｇ／ｍＬ。维生素Ｂ１２含量为０．０００５１ｍｇ／ｍＬ。干芦荟中钙含量为１０５２７．７７μｇ／ｇ、硒含量为８８．３４μｇ／ｇ、锗含量为７０．８２μｇ／ｇ。多糖质量分数为０．５６％,水分为鲜     

用钼（铕）络合物法测定四环素类抗生素的研究

利用四环素与钼、土霉素与铕的络合反应，建立了用钼、铕络和物法测定药物的新方法。检出限分别为０．５μｇ／ｍＬ，０．６μｇ／ｍＬ，线性范围分别为０．５～５０μｇ／ｍＬ和０．６～５０μｇ／ｍＬ。方法快速、简便。应用于尿中四环素的测定，结果较为满意。     

高效液相色谱法测定羊体内的丙硫咪唑缓释弹代谢产物的血药浓度

用反相高效液相色谱法追踪分析不同时间内羊血清中药物浓度的变化，以供药物代谢动力学研究。药物为丙硫咪唑砜和丙硫咪唑亚砜（简称砜和亚砜），实验条件为ＯＤＳ柱，流动相甲醇：水＝７：３（ｖ／ｖ），紫外检测波长为２９０ｎｍ。在３ｈ左右测定浓度达峰值，其最高浓度分别为４．０１μｇ／ｍＬ和１１．４７μｇ／ｍＬ，五天左右下降为２．７３μｇ／ｍＬ和１．３２μｇ／ｍＬ附近。最小检出量为０．４ｎｇ／ｍＬ及０．７ｎｇ／ｍＬ。线性关系良好。丙硫咪唑砜和亚砜的回归相关系数分别为０．９９９４和０．９９９１。采用内标法测定回收率，平均为１００±１２％。     

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.