有机合成中的高价碘应用

高价碘化物作为一种性能温和、选择性强及环境友好的氧化试剂在有机合成中得到了广泛的应用.近年来,各种不同结构的高价碘试剂和各种新的反应及应用大量涌现出来,使它们的应用领域从传统的醇类氧化扩展到一些结构复杂化合物的合成领域当中.本文以最常用和研究较多的几个高价碘化合物为例,对它们用于有机合成反应,如氧化、加成、取代和重排的最新进展进行了概述,对本研究小组重点研究的五价碘化合物邻羟基苯碘酰与酮类化合物的取代反应和烯烃化合物的加成反应也作了介绍.     

有机合成中的高价碘应用

高价碘化物作为一种性能温和、选择性强及环境友好的氧化试剂在有机合成中得到了广泛的应用。近年来,各种不同结构的高价碘试剂和各种新的反应及应用大量涌现出来,使它们的应用领域从传统的醇类氧化扩展到一些结构复杂化合物的合成领域当中。本文以最常用和研究较多的几个高价碘化合物为例,对它们用于有机合成反应,如氧化、加成、取代和重排的最新进展进行了概述,对本研究小组重点研究的五价碘化合物邻羟基苯碘酰与酮类化合物的取代反应和烯烃化合物的加成反应也作了介绍。     

2-碘酰基苯甲酸在有机合成中的研究与应用

高价有机碘化合物的反应性质与过渡金属相似,其参与的反应具有反应条件较温和、选择性好、产率高及环境友好等优点,因而近年来关于高价有机碘试剂的研究受到广泛关注,在有机合成领域中获得了较多应用.综述了近年来高价有机碘试剂2-碘酰基苯基酸(IBX)在有机合成中的研究及应用,包括IBX在氧化羟基、含氮化合物和含硫化合物,在制备α...     

有机合成中有机高价碘化合物的研究进展

对高价碘化合物用于有机合成反应，如氧化，加成，取代和交叉偶联的最新进展进行了评述，参考文献82篇。     

原位生成的高价碘试剂在有机合成中的应用进展

原位生成的高价碘试剂具有原子经济性、性能温和和绿色环保等优点,在诸多合成和不对称催化等反应中表现活跃.详细介绍了原位生成高价碘的概念以及反应机理,根据不同的反应类型分别对原位生成的三价碘、五价碘以及手性高价碘试剂在有机合成反应中的应用进行了归纳总结,分析了原位生成的高价碘试剂目前面临的问题,并对今后的发展趋势作了展望.     

有机高价碘化学简介及其应用

近几十年来,有机高价碘化学蓬勃发展,有机高价碘试剂也受到化学合成工作者的广泛关注,关于有机高价碘试剂的反应性研究也获得了迅猛发展。有机高价碘试剂作为绿色、高效、多功能化的氧化剂,通常容易制备且操作简单,与已有的合成方法相比,该类试剂参与的反应表现出了许多独特的优点,并且具有与汞、铬、铅、铊等重金属试剂类似的反应性,但却没有这些试剂所带来的毒性和环境污染问题。本文介绍了有机高价碘化学的起源与发展,高价碘试剂的结构特点与分类,高价碘试剂在有机合成、材料化学及工业合成中的应用。     

三价碘有机物在有机合成中的应用

单质碘可形成很多多价碘的化合物。其中三价碘及五价碘的有机或无机物,应用最多。这些化合物的性质,结构、制备方法,都有了详尽的报道及综述。然而,它们被大量应用于有机合成中,作为有用的有机合成中间体却是最近才有见报道。A.Varvoglis曾详细报道了一些多价碘物的合成方法,结构、性质及其在合成上的一些应用。本文将着重介绍下列五种三价碘化合物在有机合成中的一些应用:     

醋酸碘苯促进的氧化反应在构建2-氨基-1,3,4-噻二唑分子中的应用

报道了一种用高价碘试剂促进缩氨基硫脲分子内氧化偶联反应,能够有效地合成2-氨基-1,3,4-噻二唑类衍生物.高价碘可以作为温和的反应试剂,拥有毒性低、廉价可循环易操作的特性.该反应具有原料易制得、操作简便以及较好的底物适用性等特点.反应机理也进行了初步研究.     

Dess-Martin高价碘化合物在有机合成中的应用进展

简单介绍了Dess-Martin高价碘化合物(DMP)的合成方法,重点对DMP在有机合成反应中的最新应用进展进行了概述.     

分子碘催化的有机化学反应

从有机合成化学的角度,按反应类型综述了分子碘作为催化剂在有机化学中的应用,碘催化的反应主要涉及保护基团的形成和裂解、氧化和还原反应、成环反应、加成反应、取代反应和重排反应等.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.