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

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