title: Metal-free synthesis of 2-substituted (N, O, C) benzothiazoles via an intramolecular C-S bond formation.
abstract: An efficient, economical, and convenient method was developed for the preparation of 2-substituted (N, O, C) benzothiazoles from N'-substituted-N-(2-halophenyl)thioureas, O'-substituted-N-(2-halophenyl) carbamothioates, or N-(2-halophenyl) thioamides via a base-promoted cyclization in dioxane without any transition metal. A one-pot variant combining the synthesis of the thiourea and the cyclization was also demonstrated. High yields were obtained, and a variety of functional groups were tolerated under these conditions. Transition-metal-free, mild reactive conditions, wide application scope, and shorter reaction times make this method superior to the reported methods for the synthesis of 2-substituted benzothiazoles and suitable for combinatorial format.
authors.affiliation: The Center for Drug Discovery and Design, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201203, PR China.
authors.forename: Enguang
authors.initials: E
authors.lastname: Feng
authors.forename: He
authors.initials: H
authors.lastname: Huang
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.forename: Deju
authors.initials: D
authors.lastname: Ye
authors.forename: Hualiang
authors.initials: H
authors.lastname: Jiang
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
mesh_terms: D052160:Benzothiazoles / Q000138:chemical synthesis* / Q000737:chemistry; D020650:Combinatorial Chemistry Techniques; D003500:Cyclization; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D052160:Benzothiazoles