Graphene oxide-catalyzed synthesis of benzothiazoles with amines and elemental sulfur via oxidative coupling strategy of amines to imines

The graphene oxide-catalyzed coupling and cyclization reactions of primary amines with elemental sulfur was developed to afford various optically property benzothiazoles. This coupling and cyclization strategies proceeded under the oxidant system graphene oxide/O-2 and constructed carbon-heteroatom (N, S) bonds with amines and elemental sulfur. Due to benzothiazoles as common chromophores, these products exhibited intriguing fluorescence properties, including outstanding Stokes shifts (up to 161 nm) and quantum yields (up to 74%). Utilizing the products' unique fluorescence response in different solvents, beta-naphthothiazole 4a showed excellent aggregation-induced emission properties in 1,2-dichloroethane, which was 60 times higher than in tetrahydrofuran. (C) 2022 Elsevier Ltd. All rights reserved.