停流流动注射在线沉淀-原子吸收法测定盐酸苯海拉明

本文建立了一种简单快速的检测药剂中盐酸苯海拉明含量的停流流动注射在线沉淀 间接原子吸收法。该方法是基于盐酸苯海拉明与BiI-4在线定量连续生成离子对缔合物沉淀(摩尔比为1∶1),经停流过滤稀释后,以AAS法测定滤液中铋的含量来间接测定盐酸苯海拉明的量。本法的相对平均偏差小于3.5%,线性范围为2.5～40μg·mL-1,采样频率60h-1,回收率为98%～103%。     

ICP-AES法测定锡铅焊料中铜铁镉锌铝铋

锡铅焊料试样经盐酸、硝酸分解后，加入一定量的硫酸沉淀分离基体铅，以盐酸一氢溴酸排锡后，采用ICP—AES法同时测定铜、铁、镉、锌、铝、铋。方法没有谱线和背景干扰，检出限铜为0．000034％，铁为0．000038％，镉为0．000026％，锌为0．000071％，铝为0．00025％，铋为0．00060％，回收率在91．09／5～99．2％之间。完全满足锡铅焊料中的铜、铁、镉、锌、铝、铋测定的要求。     

12-钨磷酸共振瑞利散射光谱法测定盐酸苯海拉明

在pH值为0～1.5范围内,12-钨磷酸与盐酸苯海拉明(DP.HCl)反应形成缔合物后引起共振瑞利散射(RRS)强度显著增强,最大散射峰位于305nm,散射强度与DP.HCl浓度在8.0×10-9～1.6×10-6g/mL范围内成线性关系,据此建立了测定盐酸苯海拉明的RRS法。本法具有较高的灵敏度和良好的选择性,其检出限(3σ)为0.8×10-9g/mL。用于尿样中盐酸苯海拉明的测定,回收率为96.0%～104.2%。结合量子化学AM1法计算结果讨论了反应机理。     

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％。     

盐酸苯海拉明和曙红B体系的光谱研究及其分析应用

在pH 3.1的Britton-Robison缓冲介质中,曙红B与盐酸苯海拉明借助静电引力和疏水作用力形成离子缔合物,使最大散射波长为364 nm处的共振光散射光谱得到加强。研究了体系的共振光散射光谱和紫外-可见吸收光谱。建立了一种测定盐酸苯海拉明的新方法。体系共振光散射增强的强度与盐酸苯海拉明的质量浓度在0.5~11.2 mg/L范围内呈现良好的线性关系,方法的检出限为41.7μg/L。可用于药物中盐酸苯海拉明的测定。     

盐酸苯海拉明的 ICP-AES法间接测定

建立了一种间接测定盐酸苯海拉明的方法;在pH4.0时 ,将盐酸苯海拉明与Cu2 和锌试剂的三元混配络合物萃入甲基异丁酮 (MIBK)和磷酸三丁酯 (TBP)的混合萃取剂中 ,采用电感耦合等离子体原子发射光谱法(ICP -AES)测定有机相中的Cu2 ,从而间接测定盐酸苯海拉明含量;方法测定线性范围在10～100mg·L -1 ,检出限为0.35mg·L-1,回收率为76 %～107 % ,相对标准偏差 (RSD ,n=10)<3%;方法简便、快速、准确 ,线性范围宽 ,实际测定结果令人满意。     

SLS存在下meso 四(对三甲胺基苯基)卟啉测定微量铜

研究了表面活性剂十二烷基苯磺酸钠（ＳＬＳ） 存在时,ｍｅｓｏ 四（ 对三甲胺基苯基） 卟啉［Ｔ（４ ＴＭＡＰ）Ｐ］ 与铜的显色反应。在ｐＨ＝ ３ ．７ 的ＨＡｃ ＮａＡｃ 介质中,在ＳＬＳ存在下,铜与［Ｔ（４ ＴＭＡＰ）Ｐ］ 形成１∶２ 的稳定配合物,至少在４ ．５ｈ 内吸光度无变化。最大吸收波长位于４１０ｎｍ ,ε＝ ３ ．７９ ×１０５Ｌ·ｍｏｌ－ １·ｃｍ － １ 。铜在０ ～１ ．４０μｇ／２５ｍＬ内有良好线性关系。用于自来水及湖水中铜的测定,相对标准偏差小于３ ％ ,加标回收率在９８ ％ ～１０３％ 之间     

在胶束溶液中用5－Br－PADN示波极谱测定痕量铜

在ｐＨ１０．０的ＮＨ＿３·Ｈ＿２Ｏ－ＮＨ＿４Ｃｌ缓冲溶液中，当有０．００３０％ＣＴＭＡＢ存在时，Ｃｕ（Ⅱ）与５－Ｂｒ－ＰＡＤＮ配合物在－０．４５Ｖ产生一灵敏配合物吸附波，用于测定铜（Ⅱ）时，线性范围为０．００５０～０．６０μｇ／ｍＬ，检测下限为５．０×１０￣（－８）ｍｏｌ／Ｌ。所提出的方法可用于矿石中微量铜的测定，回收率在９２％～１０４％之间。     

催化动力学垂直光路光度法测定痕量铜

建立了痕量铜的催化动力学垂直光路光度测定法，铜含量在０～３．０ｎｇ／２５０μｌ范围内符合比耳定律，工作曲线的回归方程为：△Ａ＝０．５３４Ｃ（ｃｕ＾２＋，ｎｇ），＋０．０１８（ｒ＝０．９９９９），检出限为１．５×１０＾－１１ｇ．ｍｌ＾－１（△Ａ＝０．０２，ｔ＝２ｍｉｎ）由曲线斜率法求得的表观摩尔吸光系数为１．２×１０＾７，方法用于氮三乙酸及标准水样中铜的测定，加标回收率在９２％～９８％，相对标准偏差     

二极管阵列检测—偏最小二乘吸光光度法同时测定铜锌

研究了以２－（５－溴－２－噻唑偶氮）５－二乙氨基苯酚（５－Ｂｒ－ＰＡＤＡＰ）作显色剂,ＣＣＤ（Ｃｈａｒｇｅ Ｃｏｕｐｌｅｄ Ｄｅｖｉｃｅ,电荷耦器件）二极管阵列检测分光光度装置采及收光谱,用偏最小二乘法解析,同时测定了粮食中铜和锌。方法的线性范围锌为０．０５～０．４０μｇ．ｍｌ＾－１,铜为０．０２～０．６０μｇ．ｍｌ＾－１;检出限铜为０．０２μｇ．ｍｌ＾－１,平均加标回收率锌为９３．３％～９５．７     

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%.     

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 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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

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.