A convenient synthesis of 2-mercapto and 2-chlorobenzothiazoles

A convenient synthesis of 2-mercapto and 2-chlorobenzothiazoles is described. The key feature of the synthesis is an exclusive ortho-selective nucleophilic aromatic substitution reaction of ortho-haloanilines with potassium/sodium O-ethyl dithiocarbonate under mild conditions. Subsequent intra-molecular cycliza-tion affords 2-mercaptobenzothiazoles in high yields. The 2-mercaptobenzothiazoles are readily converted to corresponding 2-chlorobenzothiazoles upon treatment with sulfuryl chloride.