N-Monosubstituted 1, 2-diaminobenzenes 4 (R Me, Ph, PhCH2, and 3, 4-Me2C6H3CH2) react with 4, 5-dichloro-1, 2, 3-dithiazolium chloride 1 in dichloromethane at room temperature to give the corresponding 2-cyanobenzimidazoles 6. If pyridine is added at the beginning of the reaction, the intermediate imino-1, 2, 3-dithiazoles 5 can be isolated. Upon thermolysis, most of the imines 5 give the 2-cyanobenzimidazoles 6 in fair to good yields. ...
