Sulfur-Promoted Redox Cyclization of 2,2′-Dinitrodiphenyl Disulfides and Benzylamines

This study aims to develop green and sustainable advanced synthetic methods based on redox cyclization. Elemental sulfur has been shown to promote the efficient synthesis of 2-substituted benzothiazoles from 2,2’-dinitrodiphenyl disulfides and benzylamines via redox cyclization in the absence of transition metal catalysts and solvents. The 2-substituted benzothiazoles were obtained in good to excellent yields. This synthetic methodology is highly atom-economical and does not require any external oxidizing and/or reducing agents.