Synthesis of Dibenzo[d,f][1,3]diazepines via Elemental Sulfur-Mediated Cyclocondensation of 2,2'-Biphenyldiamines with 2-Chloroacetic Acid Derivatives

The three-component reaction of 2,2'-biphenyldiamines with 2-chloroacetic acid derivatives and elemental sulfur was developed for the practical synthesis of unknown 2-carboxamide-substituted dibenzo[d,f][1,3]diazepines. This protocol is distinguished by efficiency in water, good tolerance to functional groups and can be adapted to a large‐scale synthesis. The chemoselective preparation of a variety of 2-S,N,O-substituted dibenzo[d,f][1,3]diazepines was accomplished using the developed method.