Elemental Sulfur Promoted Cyclization of o-Chloronitrobenzenes and Aryl Isothiocyanates to Furnish 2-Aminobenzothiazoles

Abstract

Methods to afford 2-aminobenzothiazoles often involve the use of o-aminothiophenols or aniline-typed precursors. Herein we describe a method to furnish 2-aminobenzothiazoles through the cyclization of o-chloronitrobenzenes and aryl isothiocyanates with the assistance of elemental sulfur. From the perspective of step economy, our strategy allows for the direct use of nitroarene precursors without further reduction to anilines. The scope of the reaction with respect to both substrates was investigated, and it was found that electronic properties of the aryl isothiocyanate was important for obtaining acceptable yields.