Regioselective, Solvent- and Metal-Free Chalcogenation of Imidazo[1,2-<i>a</i>
]pyridines by Employing I<sub>2</sub>
/DMSO as the Catalytic Oxidation System
作者:Jamal Rafique、Sumbal Saba、Alisson R. Rosário、Antonio L. Braga
DOI:10.1002/chem.201600800
日期:2016.8.8
molecular‐iodine‐catalyzed chalcogenations (S and Se) of imidazo[1,2‐a]pyridines were achieved by using diorganoyl dichalcogenides undersolvent‐freeconditions. This approach afforded the desired products that had been chalcogenated regioselectively at the C3 position in up to 96 % yield by using DMSO as an oxidant, in the absence of a metal catalyst, and under an inert atmosphere. This mild, green approach allowed
通过在无溶剂条件下使用二有机基二卤化氢实现咪唑并[1,2- a ]吡啶的高效分子碘催化硫属元素化(S和Se)。通过使用DMSO作为氧化剂,在没有金属催化剂的情况下,并且在惰性气氛下,该方法提供了所需的产物,该产物已经在C3位置进行了区域硫磺化,产率高达96%。这种温和的绿色方法可以制备具有结构多样性的不同类型的硫族化咪唑并[1,2- a ]吡啶。此外,当前协议还扩展到其他N杂环核。
Direct, Metal-free C(sp<sup>2</sup>
)−H Chalcogenation of Indoles and Imidazopyridines with Dichalcogenides Catalysed by KIO<sub>3</sub>
作者:Jamal Rafique、Sumbal Saba、Marcelo S. Franco、Luana Bettanin、Alex R. Schneider、Lais T. Silva、Antonio L. Braga
DOI:10.1002/chem.201705404
日期:2018.3.15
synthesis of 3‐Se/S‐indoles and imidazo[1,2‐a]pyridines through direct C(sp2)−H bond chalcogenation of heteroarenes with half molar equivalents of different dichalcogenides, using KIO3 as a non‐toxic, easy‐to‐handle catalyst and a stoichiometric amount of glycerol. The reaction features are high yields, based on atom economy, easy performance on gram‐scale, metal‐ and solvent‐free conditions as well as applicability
本文中,我们报告了一种更环保的协议,该方法通过杂芳烃的直接C(sp 2)-H键硫代半数当量的不同二硫代半乳糖苷合成3-Se / S-吲哚和咪唑并[1,2- a ]吡啶KIO 3是一种无毒,易于操作的催化剂和化学计量的甘油。该反应的特征是基于原子经济性的高收率,在克级,无金属和无溶剂条件下易于操作以及适用于不同类型的N-杂芳烃。
Unconventional Reactivity with DABCO-<i>Bis</i>
(sulfur dioxide): C-H Bond Sulfenylation of Imidazopyridines
作者:Julie Le Bescont、Chloé Breton-Patient、Sandrine Piguel
DOI:10.1002/ejoc.202000112
日期:2020.4.16
Exploring the unexpected reactivity of DABCO‐bis(sulfur dioxide) on various imidazo[1,2‐a]pyridines expanded the toolbox of the sulfenylation reagent. Starting from three simple building blocks, this three‐component transformation led to various C‐3 sulfenylated substituted imidazo[1,2‐a]pyridines in moderate to good yields.
探索DABCO-双(二氧化硫)在各种咪唑并[1,2- a ]吡啶上的出乎意料的反应性,扩大了亚磺酰化试剂的工具箱。从三个简单的结构单元开始,这种由三部分组成的转化以中等到良好的产率产生了各种C-3磺化取代的咪唑并[1,2- a ]吡啶。
C3 Sulfenylation of N-Heteroarenes in Water under Catalyst-Free Conditions
We describe herein a catalyst-free selective C−H sulfenylation of imidazo[1,2-a]pyridines using sulfonothioates as odorless source of thioarylated reagent in an aqueous medium. The method works for a variety of substitutedimidazo[1,2-a]pyridines with broad functional group tolerance. The methodology has been extends to selective sulfernylation of indoles and imidazothiazoles. The sulfonothioates are
Regioselective sulfenylation of imidazoheterocycles with thiophenols at room temperature is reported. Sulfenylation is promoted by N-chlorosuccinimide under metal-free conditions with a broad range of substrate scopes.