Metal sulfide: An efficient promoter for the synthesis of 2-mercaptobenzothiazoles from 2-haloanilines and carbon disulfide

A convenient method has been developed for the preparation of a variety of 2-mercaptobenzothiazoles from 2-haloanilines and CS₂ mediated by metal sulfide. In this reaction, 2-haloanilines reacted with CS₂ in the presence of Na₂S?·?9H₂O to form 2-mercaptobenzothiazoles. Na₂S?·?9H₂O functioned both as an activator of CS₂ and as a base. Furthermore, NMR analysis was used to identify the different reaction mechanisms of 2-haloanilines and CS₂ mediated by Na₂S or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), which demonstrated that Na₂S interacted only with CS₂, while DBU reacted with both 2-iodoaniline and CS₂.