微波干法催化芳香醛与绕丹宁及N-苯基绕丹宁的缩合反应

利用微波辐射和固体碱性载体试剂催化绕丹宁及N-苯基绕丹宁和芳香醛的缩合反应合成了14个绕丹宁衍生物并研究了影响反应的因素。     

醛基螺苯并吡喃与绕丹宁的反应

醛基螺苯并吡喃与绕丹宁的反应李仲杰,刘祥（西北大学化学系,西安,７１００６９）关键词醛基螺苯并吡喃,绕丹宁,反应机理醛基螺苯并吡喃具有光致变色性质［１］．利用醛基的反应对其结构进行修饰,有可能获得新的功能分子。这类化合物与Ｗｉｔｔｉｇ试剂的反应已有报...     

苄叉绕丹宁及其类似物的N—Mannich碱合成

Mannich 反应在有机合成中占有重要地位。通过 Mannich 反应合成的化合物可以具有止痛、杀菌、杀虫、抗癌等多种生物效应。在应用 N-Mannich 反应合成的斑蝥素类似物和绕丹宁衍生物中,有些化合物具有抗癌活性。绕丹宁分子中活泼亚甲基及酰亚胺两个部位均可进行 Mannich 反应,提供新的结构类型     

2-芳基亚甲基绕丹宁的催化合成和紫外光谱的取代基效应

在 KF- A12 0 3负载型固体碱催化下 ,绕丹宁和芳香醛发生缩合反应 ,高产率地合成了 5-芳基亚甲基绕丹宁 ,测定了产物在种溶剂中的紫外光谱 ,其最大吸收频率νmaxuv与 Hammett取代基常数σ+p存在良好的线性关系。     

应用绕丹宁衍生物测定贱金属研究的国内现状

绕丹宁衍生物是光度法测定贵金属的一类传统显色剂,这类试剂容易合成,近年来涌现出一批新型绕丹宁衍生物,除测定贵金属外,已拓展到一些贱金属的分析测定.分析手段已由传统的吸光光度法向荧光光度法和催化动力学荧光分析法转移,使测定的灵敏度和选择性大大提高.根据文献检索,将国内在这一领域的研究应用现状进行介绍.     

新荧光试剂5-(4'-卤代-2'-羧基苯偶氮)绕丹宁的合成及分析化学特性研究

合成了三种新荧光试剂,5-(4'-氯-2'-羧基苯偶氮)绕丹宁(CRACP.2).5-(4'-溴-2'-羧基苯偶氮)绕丹宁(BRACP,3)及5-(4'-碘-2'-羧基苯偶氮)绕丹宁(IRACP,4).研究了它们的吸收光谱及荧光性质.探讨了分子结构与荧光性能的关系.建立了铜(Ⅱ)的荧光分析方法.在pH5.3时.CRACP与铜( Ⅱ) 形成荧光螯合物, λ~ e~ x/ λ~e~m=310nm/408nm.检测限为5×10^-^4μg/g.     

新荧光试剂5-(4''-卤代-2''-羧基苯偶氮)绕丹宁的合成及分析化学特性研究

合成了三种新荧光试剂,5—(4’—氯—2’—羧基苯偶氮)绕丹宁(CRACP,2)、5—(4’—溴—2’—羧基苯偶氮)绕丹宁(BRACP,3)及5—(4’—碘—2’—羧基苯偶氮)绕丹宁(IRACP,4).研究了它们的吸收光谱及荧光性质,探讨了分子结构与荧光性能的关系.建立了铜(Ⅱ)的荧光分析方法.在pH5.3时,CRACP与铜(Ⅱ)形成荧光螫合物,λ_(ex)/λ_(em)=310nm/408nm,检测限为5×10 ~(-4)μg/g.     

RE（Ⅲ）与5—（2‘—羧基苯偶氮）绕丹宁及其衍生物的配合物稳定常数

采用ｐＨ－电位滴定法研究了乙醇溶液中ＲＥ（Ⅲ）与新型荧试剂Ｈ２Ｌ［５－（２＇－羧基苯偶氮）］绕丹宁（Ｂｒ－ＲＡＣＰ）、５－（４＇－氯代－２＇－羧基苯偶氮）绕丹宁（Ｃｌ－ＲＡＣＰ）、５－（４＇－溴代－２＇－羧基苯偶氮）绕丹宁定常数大小为ＲＡＣＰ＞Ｃｌ－ＲＡＣＰ＞Ｂｒ－ＲＡＣＰ。而与Ｎｄ（Ⅲ）的累积生成常数ｌｇβｍｌｈ随原子序数Ｚ增大时，研究了浓度对ｌｇβｍｌｈ的影响，测定了１５种稀土与ＲＡＣＰ的ｉｇ     

对二甲胺基苯叉绕丹宁萃取滴定法测定矿石中微量银

对二甲胺基苯叉绕丹宁(PDABR)为指示剂,间接测定氰根已有报导。本文由此出发,拟定在pH5.5的乙酸-乙酸铵绥冲液中用PDABR-四氯化碳标准溶液萃取滴定矿石中微量银。汞(Ⅱ)、金(Ⅲ)、钯(Ⅱ)和铂(Ⅳ)与PDABR作用干扰测定;氯、     

一类新的贵金属显色剂——若丹宁偶氮同系物

若丹宁偶氮同系物是七十年代发展起来的一类新光度显色试剂。这类试剂与贵金属离子的显色反应具有很高的灵敏度和选择性。到目前为止,Саввин等人已发表了20余篇关于这类试剂的合成、性质和分析应用方面的研究报导。已研究过的这类化合物有:若丹宁偶氮化合物、硫代若丹宁偶氮化合物、3-取代若丹宁偶氮化合物和硫代丙酰若丹宁偶氮化合物。它们的结构通式如下:A.若丹宁偶氮化合物     

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.     

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.     

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.     

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.