Green iodination of pyrazoles with iodine/hydrogen peroxide in water
摘要:
In this Letter, we describe a practical, green iodination of pyrazoles to form the corresponding 4-iodopyrazole derivatives. The reaction takes place in water, using only 0.5 equiv of iodine and 0.6 equiv of hydrogen peroxide, a system that generates water as the only reaction by-product. (C) 2008 Elsevier Ltd. All rights reserved.
Transition-Metal-Free Selective Iodoarylation of Pyrazoles via Heterocyclic Aryliodonium Ylides
作者:Nannan Lu、Liangsen Huang、Lili Xie、Jiajia Cheng
DOI:10.1002/ejoc.201800416
日期:2018.7.13
A one‐pot transition‐metal‐free selective iodoarylation of pyrazoles with aryliodine diacetates was developed. The reaction proceeds via the generation of NH‐pyrazole‐iodonium salts in situ, followed by sequential phen/K2CO3‐mediatedintermolecular arylation. The proposed iodonium ylide intermediate could be isolated and directly affords the difunctionalization products in high yield under base‐ and
开发了吡唑与芳基碘二乙酸盐的单锅无过渡金属选择性碘芳基化反应。反应通过原位生成NH-吡唑-碘鎓盐进行,然后依次进行phen / K 2 CO 3介导的分子间芳基化。拟议中的碘鎓碘化物中间体可以被分离,并在无碱和无金属的条件下以高收率直接提供双官能化产物。
Introducing Phenalenyl-Based Organic Lewis Acid as a Photocatalyst to Facilitate Oxidative Azolation of Unactivated Arenes
作者:Partha Pratim Sen、Sudipta Raha Roy
DOI:10.1021/acs.orglett.3c00409
日期:2023.3.24
By revealing the robust photooxidant properties of phenalenyl-based organic Lewis acid, we have introduced this moiety as an effective organophotocatalyst for the oxidative azolation of unactivated and feedstock arenes. In addition to its tolerance for various functional groups and scalability, this photocatalyst was shown to be promising for the defluorinative azolation of fluoroarenes.
complex through a halogen bond or π–π interaction based on various halogenated pyrazolamines, depending on the HOMO–LUMO energy gap of the C–X bond. The reaction of halogenated pyrazol-5-amines with thiophenol derivatives proceeded in good to excellent yields. The formation of a π–π complex or halogen bonding between the halopyrazolamine and the thiolate anion was confirmed by UV/visible spectroscopy.