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
作者:Raju Dey、Brindaban C. Ranu
DOI:10.1016/j.tet.2011.09.016
日期:2011.11
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.
Facile cyclization of 2-arylethynyl aniline to 4(1H)-cinnolones: a new chemodosimeter for nitrite ions
作者:Raju Dey、Tanmay Chatterjee、Brindaban C. Ranu
DOI:10.1016/j.tetlet.2010.11.098
日期:2011.1
2-Arylethynyl anilines undergo very fast reaction (5 min) with nitrite ions in aqueous acidic media to produce 4(1H)-cinnolones which exhibit yellow color and UV absorbance at 391 nm. This reaction is irreversible and has been successfully tested for the detection of nitrite ions in water at ppm concentration. Thus, 2-phenylethynyl aniline serves as a chemodosimeter. An efficient and general method