Synthesis of Dibenzo[<i>d</i>,<i>f</i>][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 and 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.