Exogenous Photosensitizer-, Metal-, and Base-Free Visible-Light-Promoted C–H Thiolation via Reverse Hydrogen Atom Transfer
作者:Ze-Ming Xu、Hong-Xi Li、David James Young、Da-Liang Zhu、Hai-Yan Li、Jian-Ping Lang
DOI:10.1021/acs.orglett.8b03679
日期:2019.1.4
This reaction induces the cyclization of thiobenzanilides to benzothiazoles. The substrate absorbs visible light, and its excited state undergoes a reverse hydrogen-atom transfer (RHAT) with 2,2,6,6-tetramethylpiperidineN-oxyl to form a sulfur radical. The addition of the sulfur radical to the benzene ring gives an aryl radical, which then rearomatizes to benzothiazole via RHAT.
Fe-catalysed oxidative C–H functionalization/C–S bond formation
作者:Haibo Wang、Lu Wang、Jinsai Shang、Xing Li、Haoyuan Wang、Jie Gui、Aiwen Lei
DOI:10.1039/c1cc16184a
日期:——
Iron was used as the catalyst for the direct C-H functionalization/C-S bond formation under mild conditions. Various substrates could afford benzothiazoles in moderate to excellent yields. Preliminary mechanisticstudies revealed that pyridine played a crucial role for the high yields and selectivities.
One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides
The development of novel and efficient synthesismethods for 2-substituted benzazole derivatives is of interest as they are biologically active substances. Herein, a simple method for the synthesis of 2-aryl- and 2-alkyl-substituted benzazoles is described. The reaction of 2-aminophenols with thioamides at 60 °C in the presence of triphenylbismuth dichloride in 1,2-dichloroethane as a promoter afforded
2-取代苯并唑衍生物是具有生物活性的物质,因此开发新颖且有效的合成方法引起了人们的兴趣。本文描述了合成 2-芳基-和 2-烷基-取代的苯并唑的简单方法。 2-氨基苯酚与硫代酰胺在 60 °C 下,在二氯化三苯基铋的存在下,在 1,2-二氯乙烷中作为促进剂,在温和的反应条件下以中等至优异的收率提供各种 2-芳基-和 2-烷基苯并恶唑。该方法也可用于苯并咪唑和苯并噻唑的合成。本研究首次使用三苯基二氯化铋通过硫代酰胺经脱硫和氯化生产苯甲亚胺酰氯,及其在2-取代苯并唑合成中的应用。