Synthesis of 2-Arylbenzothiazoles by DDQ-Promoted Cyclization of Thioformanilides; A Solution-Phase Strategy for Library Synthesis

• DOI: 10.1055/s-2007-965929
• Publication Date: 2007-03-09T08:52:10Z
• Authors: D. Bose; Mohd. Idrees; Bingi Srikanth
• Keywords: Benzothiazole; Moiety; Dichloromethane

Several substituted benzothiazoles were synthesized by the intramolecular cyclization of thioformanilides using 2,6-dichloro-3,5-dicyano-1,4-benzoquinone (DDQ) in dichloromethane at ambient temperature high yields. The resulting 2-arylbenzothi­azoles separated from reduced DDQ byproduct 4,5-dichloro-3,6-dihydroxyphthalonitrile treatment reaction mixture with a strongly basic ion-exchange resin. This protocol offers degree flexibility regard to functional groups that can be placed on benzothiazole ring or 2-aryl moiety, which turn generates scaffolds for parallel synthesis.