诺氟沙星的交流示波极谱滴定法研究

本文报道了示波极谱滴定法测定诺氟沙星的含量。用ＰＨ４．４的ＨＡｃ－ＮａＡｃ缓冲溶液溶解药样，并与过量的四苯硼钠作用生成沉淀。过滤后，用硫酸亚铊回滴过量的Ｎａ－ＴＰＢ，由示波极谱图［ｄＥ／ｄｔ＝ｆ（Ｅ）］上ＴＰＢ切口的消失指示滴定络点，进而在该溶液中进行空白实验。     

铜合金中铜的示波滴定—四苯硼钠法

本文报道了铜合金中铜的示波滴定方法。样品酸溶后，用抗坏血酸还的Ｃｕ＾２＋为Ｃｕ＾＋，加入过量的四苯硼钠，在ＰＨ５－６的ＨＡｃ－ＮａＡｃ缓冲溶液中，定量形成Ｃｕ－ＴＰＢ沉淀，过量的ＴＰＢ＾－，以Ｔｌ＾＋标准溶液进行示波滴定，铜合金中共存元素不干扰测定。铜的测定回收率９９．８％－１００．１％。进行了多种铜合金中铜含量的测定，结果令人满意。     

烃铵盐用于示波极谱滴定法测定诺氟沙星

本文报道了以烃铵盐为滴定剂，用交流示波极谱四苯硼钠（Ｎａ－ＴＰＢ）滴定法测定诺氟沙星（ＮＦＸ）的含量。应用于胶囊样品的测定，与药典法测得结果基本一致，最大相对误差≤０．５６％，最大ＲＳＤ为０．２９％，平均回收率为１００．６％。     

交流示波极谱滴定法测定氟哌酸

交流示波极谱滴定法测定氟哌酸李彦威，宣春生，刘悦红，高惠文（太原工业大学应用化学系，太原，０３００２４）（太原制药厂）关键词交流示波极谱，示波滴定，氟哌酸氟哌酸（ＦＰＡ）在酸性溶液中能与四苯硼钠（Ｎ３－ＴＰＢ）发生缔合反应，生成白色沉淀，过量的Ｎａ－...     

乳酸环丙沙星的示波极谱滴定

１引言 乳酸环丙沙星（ＣＰＲＬ）为第三代氟喹诺四类抗生素,目前,其含量的测定主要有非水滴定法、紫外分光光度法、ＨＰＬＣ、极谱法等,但未见有示波极谱滴定法的报道。本法用四苯硼钠（Ｎａ－ＴＰＢ）作沉淀剂,在弱酸性（ｐＨ＝５．１）条件下与乳酸环丙沙星作用生成沉淀,过滤后,用硫酸亚铊标准溶液回滴滤液中过量的Ｎａ－ＴＰＢ,以ＴＰＢ在示波极谱图［ｄＥ／ｄｔ＝ｆ（Ｅ）］中的切口消失指示滴定终点。本法仪器简单,操作方便,取样量小,图形直观,终点敏锐,用于原料药样品的测定有良好的准确度和重现性,其结果与非水滴定法…     

交流示波极谱滴定法测定吡哌酸

本文介绍用交流示波极谱滴定法测定吡哌酸的含量。在ＨＣｌ－ＮａＡｃ缓冲溶液中，加入过量的Ｎａ－ＴＰＢ与吡哌酸作用生成沉淀，过滤后用亚铊标准溶液定滤液中过量的ＴＰＢ，由交流示波极谱图上ＴＰＢ的切口消失指示终点。本法操作简便，终点直观，应用于原料药样品的测定，并与药典法相对照，结果基本吻合。     

银合金中银、铜含量的示波滴定

报道了用示波滴定银合金中银、铜的含量。试样酸溶后,取部分试液,在pＨ５～６的ＨＡc－ＮaＡc缓冲介质中用四苯硼钠（Ｎa－ＴＰＢ）法示波滴定银。另取部分试液,加Ｖe使Ｃu＾２＋还原为Ｃu＾＋,用Ｎa－ＴＰＢ法示波滴定铜,而Ａg＋被还原为Ａa,避免了测定铜的干扰。该方法标准加入回收率为９９．８％～１００．２％,ＲＳＤ〈０．２％。     

铌（Ⅴ）—1—苯基—3—甲基—4—苯甲酰基—吡唑啉酮—5络合物吸附波的研究

在ｐＨ＝５．０的ＨＡｃＮａＡｃ介质中，Ｎｂ（Ⅴ）与１－苯基－３－甲基－４－苯甲酰基－吡唑啉酮－５（ＰＭＢＰ）生成络合物，于一０．９６Ｖ（ｖｓ．ＳＣＥ）出现一尖极谱波。在滴汞电极上用示波极谱仪或在悬汞电极上则吸附伏安曲线。峰电流与Ｎｂ（Ⅴ）浓度分别在０．００７５－０．８０μｇ／ｍＬ及０．００００７５－０．００７５μｇ／ｍＬ范围内呈线性关系。实验 ３     

淋必治的极谱研究

在０．１ｍｏｌ／Ｌ ＨＡｃ－ＮａＡｃ（ｐＨ４．５０）支持电解质中，淋必治（ＳＰＥ）有一灵敏的示波极谱导数还原峰，峰电位Ｅｐ＝－０．９８Ｖ（ｖｓ．ＳＣＥ）。峰电流与ＳＰＥ的浓度在２．０×１０＾－７￣８．０×１０＾－５ｍｏｌ／Ｌ范围内呈线性关系，最低检出限为５．０×１０＾－８ｍｏｌ／Ｌ。该法用于注射针剂中ＳＰＥ含量的测定。，结果良好。文中对ＳＰＥ的极谱行为、电极过程及反应机理进行了探讨。     

美洛昔康的单扫示波极谱法

在ＨＡｃ－ＮａＡｃ（ｐＨ４．７６）底液中,用单扫示波极谱法可以得到一个灵敏的美洛昔康二阶导数还原峰,其峰电位Ｅｎｐ＝－１．２８Ｖ（ｖｓ．ＳＣＥ）。峰电流与美洛昔康 度在９．０＊１０＾－８－６．０＊１０＾－６ｍｏｌ／Ｌ范围内呈线性关系（ｒ＝０．９９９４）检出限为３．０＊１０＾－８ｍｏｌ／Ｌ。该法应用于片剂中美洛昔康含量的测定,结果令人满意。     

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.     

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.