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Sulfonyl Ketenimines as Key Intermediates in One‐Pot Synthesis of N‐Sulfonyl‐2‐alkaneimidoyl Selenocyanates 下载免费PDF全文
Sulfonyl‐ketenimine intermediates, generated by the addition of Cu acetylides to sulfonyl azides, are trapped by KSeCN to afford N‐sulfonyl‐2‐alkaneimidoyl selenocyanates in moderate‐to‐good yields. 相似文献
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吴兆轩 Heriberto Diaz Velazquez 闵梦蝶 原晔 Hussein A. Younus 陈建 Bibimaryam Mousavi Francis Verpoort 《化学通报》2015,78(3):220-225
近年来,催化CO2合成精细化学品的研究备受关注。本研究在温和条件下利用金属双氮杂环卡宾催化剂实现CO2与末端炔烃的直接羧化反应,并提出合理的催化机理。首先,合成制备了铜基、银基两种金属双氮杂环卡宾催化剂,实验证明银双氮杂环卡宾配合物具有较好催化活性。通过改变环境条件和底物种类,对反应条件及催化剂底物适应性进行了探究,利用核磁共振谱仪表征产物分子结构并计算直接羧化反应的催化产率。结果表明,适宜催化条件为:1.2eq Cs2CO3作为添加剂、1大气压、室温、无水溶剂和1(mmol)%催化剂用量。银基金属催化剂活性较铜基催化剂高并具有广泛的底物适应性,对苯乙炔的催化产率高达93%;对乙炔气体同样具有良好的催化活性。此类催化剂具有优良的催化活性,能催化合成丙炔酸等重要医药中间体,在工业应用上具有极大潜力和广阔前景。 相似文献
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The dynamical viscoelasticity of ABS melts with different particle size was investigated at various levels of rubbery phase contents. The effects of the rubber are more pronounced in the terminal zone: a transition from viscoelastic liquid to viscoelastic solid behavior was observed which can be interpreted as a physical gelation occurring at a critical rubbery phase content. This critical content resulted in being smaller in the case of smaller particles. A quantitative explanation of the experimental findings was proposed in terms of the average interparticle distance and overlapping of the chains grafted onto the neighboring rubber particles. The gel-like transition appeared to correspond to an approximately constant level of grafted chains overlapping.Presented in part at the Symposium Recent Developments in Structured Continua, Montreal (Canada), 26–28 May 1993. 相似文献
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工程机械显示终端是重要的人机交互界面,随着工程机械控制系统信息化和智能化水平的不断提高,对车载显示终端也提出了越来越高的要求。为了满足需求,研制了基于i.MX35的工程机械显示终端,该显示终端以i.MX35多媒体应用处理器为核心,采用CODESYS作为应用编程平台,实现了人机界面显示、CAN总线通信、摄像头视频采集、大容量数据存储等功能,具有显示性能强大、启动速度快、应用编程灵活、易于扩展等特点,可以广泛应用于各种工程机械控制系统中。 相似文献
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Dr. David Tejedor Samuel Delgado-Hernández Lucía Colella Dr. Fernando García-Tellado 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(66):15046-15049
A universal, practical and scalable organocatalytic hydrocyanation manifold to provide β-substituted acrylonitriles bearing an electron-withdrawing functionality has been implemented. The catalytic manifold operates under the reactivity generation principle “a good nucleophile generates a strong base”, and it uses 1,4-diazabicyclo[2.2.2]octane (DABCO) as the catalyst, activated terminal alkynes as substrates and acetone cyanohydrin as the cyanide source. The acrylonitriles obtained as E,Z mixtures are straightforwardly resolved by simple flash chromatography delivering the pure isomers in preparative amounts. 相似文献
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We have synthesized a homologous series of azoesters consisting of a coumaryl moiety as the end group. Eleven derivatives of this series exhibit mesomorphism. The nematic mesophase is exhibited from ethyl homologue onward, while the smectic phase commences at the pentyl derivative and is exhibited along with the nematic phase up to the hexadecyl derivative. The N-I transition temperatures curves show the usual odd-even effect. All the compounds in this series are thermally stable and exhibit a wide mesomorphic range of nearly 120°C. Their thermal stabilities and other characteristics are discussed. 相似文献
9.
A one‐pot method for synthesis of reduced graphene oxide‐supported Cu–Cu2O and catalytic application in tandem reaction of halides and sodium azide with terminal alkynes 下载免费PDF全文
Zhuofei Li Hongyan Zhao Huatao Han Jinyi Song Yang Liu Weihao Guo Zhizhong Sun Wenyi Chu 《应用有机金属化学》2018,32(4)
Reduced graphene oxide (RGO)‐supported Cu–Cu2O nanocomposite material (Cu‐Cu2O@RGO) was prepared through a one‐pot reflux synthesis method. The morphology, crystal structure and composition of the prepared Cu‐Cu2O@RGO were characterized using transmission electron microscopy, X‐ray diffraction, and X‐ray photoelectron, infrared and Raman spectroscopies. Cu‐Cu2O@RGO as a heterogeneous catalyst was applied to tandem reactions of halides and sodium azide with terminal alkynes to synthesize effectively 1,4‐disubstituted 1,2,3‐triazoles. Moreover, the catalyst showed excellent recyclability performance with very little leaching of the metal. Compared with homogeneous catalysts, Cu‐Cu2O@RGO as a green and efficient catalyst was recoverable, easy to separate and highly stable in the tandem method for the synthesis of 1,2,3‐triazole compounds. 相似文献
10.
Xueling Mo Bin Chen Prof. Dr. Guozhu Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(33):14102-14106
An asymmetric copper-catalyzed Sonogashira type coupling between alkynes and α-bromoamides has been developed. This method represents a facile approach to synthetically useful β, γ-alkynyl amides from two readily available starting materials in a highly enantioselective manner. A Bisoxazoline diphenylanaline (BOPA) serves as the effective chiral ligand. Preliminary mechanistic studies support the formation of alkyl radical species . 相似文献