The Synthesis of Aminobenzothiazoles from 2,3-Biaryl-5-anilino-Δ³-1,2,4-thiadiazolines

Abstract

2-Amidinobenzothiazoles 4 can be prepared in high yields by a thermally-promoted rearrangement of thiadiazolium salts 1 or thiadiazolines 2. Addition of base to the rearrangement of the thiadiazolium salts can improve the yields by the prior conversion of the thiadiazolium salts to the corresponding thiadiazoline free bases. The rearrangement of the thiadiazolines may go through an electrophilic aromatic substitution or free radical pathway.

Acknowledgment

The authors would like to thank Dr. Dennis Hlasta for useful discussions, support, and encouragement, and Diane Gauthier for performing many of the NMR experiments.