Thermally Induced Cyclization of Electron-Rich N-Arylthiobenzamides to Benzothiazoles
摘要:
Heating N-(2-methoxyphenyl)benzenecarbothioamides in refluxing nitrobenzene for 24 hours gives the corresponding benzothiazoles with intramolecular ipso substitution of the orthomethoxy substituent. The thermal cyclization of various other N-arylthiobenzamides is also explored.
Heating N-(2-methoxyphenyl)benzenecarbothioamides in refluxing nitrobenzene for 24 hours gives the corresponding benzothiazoles with intramolecular ipso substitution of the orthomethoxy substituent. The thermal cyclization of various other N-arylthiobenzamides is also explored.
Conversion of thiobenzamides to benzothiazoles via intramolecular cyclization of the aryl radical cation
作者:Nadale K. Downer-Riley、Yvette A. Jackson
DOI:10.1016/j.tet.2008.06.023
日期:2008.8
A new and general method has been developed for the intramolecular cyclization of thiobenzamides to benzothiazoles via aryl radicalcations as reactive intermediates. The method utilizes phenyliodine(III) bis(trifluoroacetate) (PIFA) in trifluoroethanol or cerium ammonium nitrate (CAN) in aqueous acetonitrile at room temperature to effect cyclization within 30 min in moderate yields.