We report an improved procedure using solid-supported triphenylphosphine for the concise synthesis of biologically relevant 2-phenylbenzothiazoles featuring a variety of substituents on both the benzothiazole and phenyl rings. Substituted 2-phenylbenzothiazoles were synthesized by heating equimolar quantities of 2-aminothiophenol disulfides with benzaldehydes and p-toluenesulfonic acid in the presence of polymer-supported triphenylphosphine in dimethylformamide/toluene.
Appealing features of this new method include simple isolation of product (removal of phosphine oxide by-product by filtration), avoidance of column chromatography, and good yields of substituted 2-phenylbenzothiazole products. Supplemental materials are available for this article.
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