The copper-catalyzed asymmetric [3 + 3] annulation of ethynyl benzoxazinanones with pyrazolones has been achieved, providing simple access to 1,4-dihydropyrano[2,3-c]pyrazole derivatives in moderate to excellent yields with excellent enantioselectivities (up to 99% ee). Compared with previous annulation reactions of copper–allenylidenes from ethynyl benzoxazinanones, the current reaction fused the
乙炔基苯并恶嗪酮与吡唑啉酮的铜催化不对称环化[3 + 3]已实现,可轻松获得1,4-二氢吡喃并[2,3- c ]吡唑衍生物,且产率中等至优异,对映选择性极佳(高达99 %ee)。与以前的乙炔基苯并恶嗪酮的铜-亚烯基环化反应相比,当前反应将炔丙基部分的三个碳原子融合成杂环骨架。
Potassium iodide promoted thiolation of pyrazolones and benzofurans using aryl sulfonyl chlorides as sulfenylation reagents
作者:Xia Zhao、Xiaoyu Lu、Aoqi Wei、Xiaoliang Jia、Jun Chen、Kui Lu
DOI:10.1016/j.tetlet.2016.10.053
日期:2016.11
thioethers as well as 2-aryl and 3-aryl benzofuran thioethers by employing aryl sulfonyl chlorides as sulfenylation reagents in the presence of triphenylphosphine was developed. Potassium iodide was found to facilitate the transformation for the first time by generating more reactive sulfenyl iodide in situ from sulfenyl chloride.
p-Toluenesulphonic acid-promoted, I<sub>2</sub>-catalysed sulphenylation of pyrazolones with aryl sulphonyl hydrazides
作者:Xia Zhao、Lipeng Zhang、Tianjiao Li、Guiyan Liu、Haomeng Wang、Kui Lu
DOI:10.1039/c4cc05237d
日期:——
Aryl pyrazolone thioethers were synthesized via the I2-catalysed cross-coupling of pyrazolones with aryl sulphonyl hydrazides in the presence of p-toluenesulphonic acid, which has been proposed to promote the reaction by facilitating the decomposition of sulphonyl hydrazides.
A new regiospecific synthesis method of 1 H -pyrazolo[3,4- b ]quinoxalines – Potential materials for organic optoelectronic devices, and a revision of an old scheme
using a new synthetic pathway: reductive cyclization of appropriate 5-(o-nitrophenyl)-pyrazoles with ferrous oxalate or triphenylphosphine. The main advantage of this procedure is that, contrary to the older protocols of pyrazolo[3,4-b]quinoxaline synthesis, this method allows for a substituent to be introduced to the carbocyclic ring without the formation of isomers. The pyrazole ring can also be modified
使用一种新的合成途径制备了一系列6-取代的1,3-二苯基-1H-吡唑并[3,4- b ]喹喔啉:将适当的5-(邻硝基苯基)-吡唑与草酸亚铁或三苯基膦。该方法的主要优点是,与吡唑并[3,4- b ]喹喔啉合成的旧方案相反,该方法允许将取代基引入碳环而不形成异构体。吡唑环也可以进行一定程度的修饰。此外,我们提出了一种新的机制,据报道,邻苯二酚之间的缩合反应可用于最古老的吡唑并[3,4- b ]喹喔啉合成。-苯二胺和3,4-吡唑啉-5-二酮。
Selective C-acylation of CH-active dicarbonyl compounds with ketenylidenetriphenylphosphorane: syntheses and structures of 3-phosphoranylideneacyltetronic acids, 3-phosphoranylideneacyl-4-oxocoumarins, and 4-phosphoranylideneacylpyrazol-5-ones
4-hydroxycoumarins furnish the respective 3-acylylidic derivatives, and pyrazol-5-ones exclusively yield the corresponding 4-acylylidic compounds despite the possibility of tautomerism. X-Ray single crystal structure and NMR analyses of the product tricarbonyl ylides are presented and structure–reactivity interdependencies are discussed. As a rule, compounds with wide-spread conjugation of the π-system like 9/13 do