Synthesis of 2-Arylbenzothiazoles by DDQ-Promoted Cyclization of Thioformanilides; A Solution-Phase Strategy for Library Synthesis
作者:D. Bose、Mohd. Idrees、Bingi Srikanth
DOI:10.1055/s-2007-965929
日期:2007.3
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 in high yields. The resulting 2-arylbenzothiazoles were separated from the reduced DDQ byproduct 4,5-dichloro-3,6-dihydroxyphthalonitrile by treatment of the reaction mixture with a strongly basic ion-exchange resin. This protocol offers a high degree of flexibility with regard to the functional groups that can be placed on the benzothiazole ring or 2-aryl moiety, which in turn generates scaffolds for parallel synthesis.
数种取代苯并噻唑通过分子内环化,在高产率下合成,以硫代酰胺与2,6-二氯-3,5-二氰基-1,4-苯醌(DDQ)在二氯甲烷中室温反应。所得到的2-芳基苯并噻唑可通过用强碱性离子交换树脂处理反应混合物,从还原型DDQ副产物(4,5-二氯-3,6-二羟基邻苯二腈)中分离出来。本方法在苯并噻唑环或2-芳基部分上引入官能团具有高度的灵活性,进而为平行合成提供了骨架。