Unconventional approaches for synthesis of 2-substituted benzothiazoles

Benzothiazoles are among the most important heterocycles in pharmaceuticals, natural products, and functional materials. Hence, developing direct and sustainable routes by replacing hazardous/toxic thiol reagents with nontoxic reagents for constructing 2-substituted benzothiazoles is of utmost importance. In this review, we have highlighted many synthetic methods for the synthesis of 2-substituted benzothiazoles from different starting materials under transition metal catalysis or metal-free systems.