Convenient Synthesis of Substituted 2-Phenylbenzothiazoles Using Solid-Supported Triphenylphosphine

Abstract

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.

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GRAPHICAL ABSTRACT

Keywords:

• Antitumor agents
• bicyclic compounds
• heterocycles
• 2-phenylbenzothiazoles
• solid-supported reagent

ACKNOWLEDGMENTS

We thank the School of Pharmacy and Pharmaceutical Sciences, Cardiff University, for PhD studentship funding (A. A. W.), and the EU Erasmus scheme for visiting student support (J. F.). The EPSRC National Mass Spectrometry Centre (Swansea, UK) is acknowledged for accurate mass determinations.