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
Expedient Access to Unsymmetrical Diarylindolylmethanes through Palladium-Catalyzed Domino Electrophilic Cyclization–Extended Conjugate Addition Approach
作者:Virsinha Reddy、Ramasamy Vijaya Anand
DOI:10.1021/acs.orglett.5b01030
日期:2015.7.17
A palladium-catalyzed domino process to access unsymmetrical diarylindolylmethanes has been developed through the annulation of o-alkynylanilines followed by 1,6-coojugate addition with p-quinone methides (p-QMs) under relatively mild conditions. The broad substrate scope of this methodology was demonstrated through the use of a wide range of substituted o-alkynylanilines and p-quinone methides, and in most cases, the unsymmetrical diarylindolylmethaties could be prepared in moderate to excellent yields. Notably, this method does not require any amino group protection. Moreover, 100% atom economy makes this transformation attractive from a green chemistry perspective.
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.
Mn(OAc)<sub>3</sub>-Mediated One-Pot Condensation-Oxidative Annulation of 2-Alkynylanilines and 1,3-Ketoesters: Synthesis of 2-Substituted Quinolines