硫脲类化合物合成方法研究进展

硫脲类化合物应用广泛,按不同的合成原料、试剂、溶剂和催化剂等对合成方法进行了分类,重点综述了近十年硫脲类化合物合成方法研究新进展.     

1,2,4-噻二唑的合成及其在药物化学中的应用

1,2,4-噻二唑是一类重要的杂环化合物.独特的生物和生理活性使其在药物化学领域有着非常广泛的应用.从简单底物出发,该类化合物的合成方法被不断报道.其中,碘催化、光催化等合成方法以原料易得、简单高效、绿色无污染等优势,已经广泛地被应用于1,2,4-噻二唑的合成.本文对1,2,4-噻二唑的合成方法以及在药物化学上的应用做了简要介绍.     

取代吡啶甲酰硫脲类化合物的合成及生物活性测定

在新农药创制中,杂环化合物已成为其发展的主流,其中吡啶类杂环化合物具有广泛的生物活性.近十几年来,有许多新的吡啶类农药相继商品化,成为研究领域的热点,同时,酰基硫脲类化合物也具有较好的杀菌、除草和植物调节作用.为此,为了寻找新的活性物质,在创制新农药的研究中做一些基础工作,本文以酰基硫脲为骨架,将嘧啶环及取代吡啶环引入到该结构中,利用相转移催化法设计合成了一系列未见文献报道的取代吡啶甲酰硫脲类化合物,其结构经元素分析,IR和1H NMR得到确证.初步的生物活性测试结果表明部分化合物具有较好的除草活性.     

N,N‘—二芳基硫脲类化合物的合成

N,N′-二芳基硫脲类化合物中有不少具有显著的生物活性和潜在的医学用途。许多学者进行了这一方面的合成工作。为了进一步研究不同的取代基团对此类化合物生物活性的影响,作者以丙酮为溶剂,在三乙胺的催化下,通     

环钯化合物在Heck反应中的应用研究

钯催化交叉偶联反应在化学工业、合成天然产物及生物活性物质中有着广泛的应用。催化剂体系是交叉偶联反应研究的核心。环钯化合物结构简单、性能稳定,在催化交叉偶联反应中具有高活性、高选择性,引起研究者们的极大关注,不断有新的环钯化合物被合成出来,其催化性能也得到了研究。本文综述了环钯化合物的合成方法及其在Heck反应中的应用。     

环钯化合物在Heck反应中的应用研究

钯催化交叉偶联反应在化学工业、合成天然产物及生物活性物质中有着广泛的应用.催化剂体系是交叉偶联反应研究的核心.环钯化合物结构简单、性能稳定,在催化交叉偶联反应中具有高活性、高选择性,引起研究者们的极大关注,不断有新的环钯化合物被合成出来,其催化性能也得到了研究.本文综述了环钯化合物的合成方法及其在Heck反应中的应用.     

环钯化合物在Heck反应中的应用研究

钯催化交叉偶联反应在化学工业、合成天然产物及生物活性物质中有着广泛的应用.催化剂体系是交叉偶联反应研究的核心.环钯化合物结构简单、性能稳定,在催化交叉偶联反应中具有高活性、高选择性,引起研究者们的极大关注,不断有新的环钯化合物被合成出来,其催化性能也得到了研究.本文综述了环钯化合物的合成方法及其在Heck反应中的应用.     

不对称催化构建硅立体中心化合物的新反应体系研究进展

过去二十年以来,硅立体中心手性有机硅化合物在有机合成、材料科学和药物设计等领域引起了广泛关注.然而,有机硅化合物的来源局限性大大限制了其在这些领域的应用拓展.因此,发展高效、高选择性的不对称催化合成方法以获得硅立体中心手性有机硅化合物是亟需解决的挑战性难题.主要综述了2011年以来通过不对称催化合成硅立体中心手性有机硅化合物的最新研究进展.     

苯并咪唑类化合物催化合成的研究进展

苯并咪唑类化合物在医药、农药等方面具有广泛的应用,因此这类化合物合成的新方法备受关注.从合成苯并咪唑类化合物的不同的原料出发,综述了近年来催化合成苯并咪唑化合物的研究新进展.     

二芳酰基及二芳氧乙酰基芳二硫脲衍生物的合成及植物生长调节活性

用相转移催化法将具有良好植物生长调节活性的取代芳氧乙酸(取代芳酸)与芳二胺反应合成了15个双酰基硫脲类化合物，其结构经元素分析、IR和1H NMR确证。生物活性测试结果表明，多数化合物具有较好的植物生长调节活性，个别化合物的活性尤为显著。     

Hydrogen‐Bond‐Mediated Asymmetric Catalysis

The utilization of hydrogen bonding as an activation force has become a powerful tool in asymmetric organocatalysis. Significant advances have been made in the recent past in this emerging field. Due to space constraints, this Focus Review summarizes only the key aspects with an emphasis on catalysis based on chiral ureas and thioureas, diols, and phosphoric acids. The examples provided neatly demonstrate that chiral ureas and thioureas, diols, and phosphoric acids display effective and unique activation modes of catalysis for a broad spectrum of asymmetric organic transformations, including single‐step and multiple‐step cascade reactions. These functionalities, which have the ability to afford efficient H‐bond activation of electrophiles including C?O, C?N, aziridines, and epoxides, have established their status as “privileged” functional groups in the design of organocatalysts.     

Achiral Trisubstituted Thioureas as Secondary Ligands to CuI Catalysts: Direct Catalytic Asymmetric Addition of α‐Fluoronitriles to Imines

Thioureas have emerged as effective hydrogen‐bonding catalysts over the last two decades, and they are broadly utilized in asymmetric catalysis. We report that achiral trisubstituted thioureas function as beneficial secondary ligands to Cu^I catalysts, thereby enabling highly diastereo‐ and enantioselective addition of α‐fluoronitriles to imines. The structure of the thiourea significantly affects the reaction outcome, and kinetic experiments indicate that the thioureas enhance the stereocontrol by binding to the Cu^I complex. The reaction products can be readily transformed into valuable β‐amino acid derivatives bearing a fluorinated tetrasubstituted stereogenic center.     

Double diastereocontrol in bifunctional thiourea organocatalysis: iterative Michael-Michael-Henry sequence regulated by the configuration of chiral catalysts

The importance and reactivity consequences of the double diastereocontrol in noncovalent bifunctional organocatalysis were studied. The results suggest that the bifunctional thioureas can have synthetic limitations in multicomponent domino or autotandem catalysis. Nevertheless, we provided a means to exploit this behavior and used the configuration of the chiral catalyst as a control element in organo-sequential reactions.     

硒脲及其衍生物的合成和应用

硒脲及其衍生物具有抗真菌、抗肿瘤、抗癌等生物活性,可作为合成其它化合物的中间体和配体,还可用于增强显影剂的感光度。硒脲及取代硒脲的合成有取代脲法、氨腈法、异硒氰酸酯法等,缩氨基硒脲的合成有硒氰酸盐法和取代硫脲法,酰基硒脲的合成用常规法和相转移催化法。本文对硒脲及其衍生物的上述合成方法和应用作了介绍。     

Phase Transfer Catalyzed Synthesis under Ultrasonic Irradiation and Bioactivity of N''''-(4,6-Disubstituted-pyrimidin-2-yl)-N-(5-aryl-2-furoyl) Thiourea Derivatives

Acylthiourea derivatives are useful as pesticides, herbicides, fungicides and regulator for plant growth, and also as important intermediates in the organic synthesis. In recent years, phase transfer catalysis reaction technique has been widely recognized as an efficient synthetic tool and attracted much attention. In view of these observations, a series of 5-aryl-2-furoyl thioureas containing substituted pyrimidine ring were synthesized using PEG-400 as solid-liquid phase transfer catalyst under ultrasonic irradiation. All of the new compounds have been exactly determined by IR, 1H NMRand elemental analysis.     

Synthesis of unsymmetrical sulfamides and polysulfamides via SuFEx click chemistry

As hydrogen-bond donors and acceptors, N,N′-disubstituted sulfamides have been used in a range of applications from medicinal chemistry to anion-binding catalysis. However, compared to ureas or thioureas, the utilization of this unique moiety remains marginal, in part because of a lack of general synthetic methods to access unsymmetrical sulfamides. Specifically, polysulfamides are a virtually unknown type of polymer despite their potential utility in non-covalent dynamic networks, an intense area of research in materials science. We report herein a practical and efficient process to prepare unsymmetrical sulfamides via Sulfur(vi)-Fluoride Exchange (SuFEx) click chemistry. This process was then applied to synthesize polysulfamides. Thermal analysis showed that this family of polymers possess high thermal stability and tunable glass transition temperatures. Finally, hydrolysis studies indicated that aromatic polysulfamides could be recycled back to their constituting monomers at the end of their life cycle.

A general, practical, and efficient synthesis of N,N′-disubstituted sulfamides has been developed and applied to the preparation of polysulfamides, a virtually unknown class of polymers.     

Preparation of imidazolinium salts by the Pd-catalyzed reduction of thioureas with triethylsilane and trialkylsilyl triflate

A Pd-catalyzed method for the preparation of imidazolinium salts from the corresponding thioureas that could then be used for the synthesis of imidazolium and amidinium salts is described. This method has great potential because all the required reagents are readily available and thioureas are safely converted to their corresponding precursors of NHCs under mild conditions.     

Metal-Free C−H Borylation of N-Heteroarenes by Boron Trifluoride

Organoboron compounds are essential reagents in modern C−C coupling reactions. Their synthesis via catalytic C−H borylation by main group elements is emerging as a powerful tool alternative to transition metal based catalysis. Herein, a straightforward metal-free synthesis of aryldifluoroboranes from BF₃ and heteroarenes is reported. The reaction is assisted by sterically hindered amines and catalytic amounts of thioureas. According to computational studies the reaction proceeds via frustrated Lewis pair (FLP) mechanism. The obtained aryldifluoroboranes are further stabilized against destructive protodeborylation by converting them to the corresponding air stable tetramethylammonium organotrifluoroborates.     

Adsorption and electro-oxidation of <Emphasis Type="Italic">N</Emphasis>-alkyl and <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>’-dialkyl thioureas on gold electrodes in acid solutions. A combined FTIRRAS and voltammetry study

The adsorption and electro-oxidation of N-alkyl and N,N’-dialkyl thioureas on polycrystalline gold in aqueous acid solutions is studied by Fourier-transformed infrared reflection absorption spectroscopy (FTIRRAS) and voltammetry. The potential ranges for different electrochemical processes, including electrodissolution of gold and electro-oxidation of thioureas, are determined by cyclic voltammetry. The gradual depletion of thioureas and the progressive formation of products from adsorbed and soluble species in the thin solution layer in contact with the electrode are followed through changes in band intensity of infrared (IR) spectra. Adsorbates of thioureas are formed at 0.05 V and remain on the surface up to E = 1.2 V, a potential at which their electro-oxidation takes place. Irrespective of the type of thiourea, the first electro-oxidation process from soluble thioureas starts at ca. 0.45 V with the formation of their respective disulphide. This process is preceded by the electrodissolution of gold via the formation of gold–thiourea soluble complex species. From ca. 1.2 V upwards the second electro-oxidation process results in the formation of carbon dioxide, sulphate ions and C≡N-containing species. The latter are produced only from N-alkyl thioureas, in which the presence of free amine groups makes the formation of a C≡N bond possible, as a previous stage to the production of carbon dioxide and sulphate ions as final products. From the correlation between voltammetric and spectroscopic data a general reaction pathway for the adsorption of thioureas and their electro-oxidation on gold is advanced. This work is dedicated to Prof. Teresa Iwasita on the occasion of her 65th birthday.     

Pathways of Intramolecular Cyclization of Phosphorylated Ureas and Thioureas: A Theoretical Study

The stability of phosphorylated ureas and thioureas containing various substituents at the P and N atoms and the stability of their cyclization products, the corresponding diazaphospholidines and/or oxaza(thiaza)phospholines, was evaluated by PM3, MNDO, and DFT calculations. The thermal effects of cyclizations involving phosphorylated ureas (or thioureas) and of separate steps of their synthesis were calculated. According to the calculations, diazaphospholidine structures are preferably formed from substituted ureas and thiazaphospholine structures, from their thio analogs; formation of five-membered heterorings with the P-N bond is thermodynamically preferable as compared to their six-membered analogs.