A convenient and efficient protocol for the synthesis of 4(1H)-cinnolones, 1,4-dihydrocinnolines, and cinnolines in aqueous medium: application for detection of nitrite ions
摘要:
3-Aryl/alkyl-4(1H)-cinnolones are obtained in one step from 2-aryl/alkylethynyl aniline by reaction with sodium nitrite and dilute hydrochloric acid via Richter cyclization. The alkyl cinnolones on reduction with Sn/HCl furnish 1,4-dihydro-3-alkylcinnolines, which are converted to 3-alkylcinnolines by treatment with NaNO2/HCl/KI. The whole process is carried out in aqueous medium at ambient temperature within a short reaction period. The reaction of 2-phenylethynyl aniline exhibits yellow color with UV absorbance at 391 nm and has been successfully tested for the detection of nitrite ions in water at parts per million concentration. (C) 2011 Elsevier Ltd. All rights reserved.
A General Method to Diverse Cinnolines and Cinnolinium Salts
作者:Dongbing Zhao、Qian Wu、Xiaolei Huang、Feijie Song、Taiyong Lv、Jingsong You
DOI:10.1002/chem.201300155
日期:2013.5.10
Rhodium catalysis: A highly efficient and general method has been established to prepare cinnolines, cinnolinium salts, and polycyclic cinnolinium salts through the rhodium(III)‐catalyzed oxidative CHactivation/cyclization of azo compounds with alkynes (see scheme). Key features of this methodology include the unprecedented capacity to create both cinnoline and cinnolinium frameworks.