Direct synthesis of 2-cyanobenzimidazoles and the generation of S2

Article abstract of DOI:10.1016/0040-4039(96)00853-2

2-Cyanobenzimidazoles 6 are readily prepared from 1,2-diaminobenzenes 4 and 4,5-dichloro-1,2,3-dithiazolium chloride 1, either directly or through thermal or acid-catalysed rearrangement of the isolated imine intermediates 5; thermolysis of the imine 5b at 140-150°C simultaneously generates diatomic sulfur, S₂, as shown by its interception.