5929-72-6Relevant articles and documents
-
Shergina,S.I. et al.
, (1977)
-
-
Landor,S.R. et al.
, p. 129 - 137 (1975)
-
In Situ Synthesis of CuN4/Mesoporous N-Doped Carbon for Selective Oxidative Crosscoupling of Terminal Alkynes under Mild Conditions
Cao, Yue,Gu, Dong,Lei, Aiwen,Liang, Zhenjin,Su, Yaqiong,Wu, Jinsong,Wu, Yong,Xiao, Wei,Yang, Dali,Yu, Ruohan,Zhang, Dongchao,Zhang, Yuanteng
, (2021/12/23)
The 1,3-conjugated diynes are an important class of chemical intermediates, and the selective crosscoupling of terminal alkynes is an efficient chemical process for manufacturing asymmetrical 1,3-conjugated diynes. However, it often occurs in homogenous conditions and costs a lot for reaction treatment. Herein, a copper catalyzed strategy is used to synthesize highly ordered mesoporous nitrogen-doped carbon material (OMNC), and the copper species is in situ transformed into the copper single-atom site with four nitrogen coordination (CuN4). These features make the CuN4/OMNC catalyst efficient for selective oxidative crosscoupling of terminal alkynes, and a wide range of asymmetrical and symmetrical 1,3-diynes (26 examples) under mild conditions (40?°C) and low substrates ratio (1.3). Density functional theory (DFT) calculations reveal that the aryl–alkyl crosscoupling has the lowest energy barrier on the CuN4 site, which can explain the high selectivity. In addition, the catalyst can be separated and reused by simply centrifugation or filtration. This work can open a facile avenue for constructing single-atom loaded mesoporous materials to bridge homogeneous and heterogeneous catalysis.
Strategy to isolate ionic gold sites on silica surface: Increasing their efficiency as catalyst for the formation of 1,3-diynes
Didó, Cezar A.,Coelho, Felipe L.,Closs, Maurício B.,Deon, Monique,Horowitz, Flavio,Bernardi, Fabiano,Schneider, Paulo H.,Benvenutti, Edilson V.
, (2020/02/11)
A new strategy is presented to obtain an efficient heterogeneous gold catalyst constituted by isolated ionic gold sites, which is known to be effective in alkyne coupling reaction. The procedure is based on a significant difference between offered gold amount and available adsorbent sites on the support, ensuring the formation of very active isolated gold ion sites. In order to achieve this purpose, mesoporous silica xerogel was grafted with an ionic silsesquioxane containing charged ammonium quaternary group. The modified silica showed 0.25 mmol of cationic sites per gram of material and presented thermal stability up to 200 °C. This material was applied as support for immobilization of Au(III) ions as square planar AuCl4? complex. The gold amount offered was just 12 % of the exchangeable capacity. The catalyst was efficiently applied in the cross coupling reactions, in which only 0.22 mol% was applied to obtain symmetric and non-symmetric 1,3-diynes.
SUBSTITUTED IMIDAZOLECARBOXYLATE DERIVATIVES AND THE USE THEREOF
-
Paragraph 0912-0914, (2020/12/08)
A compound is shown in formula (I). The derivatives of the compound include a stereoisomer, a pharmaceutically acceptable salt, a solvate, a prodrug, a metabolite, a deuterated derivative. The compound is a structurally novel substituted imidazole formate derivative. Substituted imidazole formate derivatives are used in preparing a drug with sedative, hypnotic and/or anesthetic effects, as well as a drug that can control the state of epilepsy. The compound has a good inhibitory effect on the central nervous system, and provides a new option for clinical screening of and/or preparation of a drug with sedative, hypnotic and/or anesthetic effects and controlling the state of epilepsy.
