Synthesis of Pyridodiazepinediones by Using the Ugi Multicomponent Reaction

Benzodiazepines show a broad spectrum of biological activities. In an ongoing effort to extend molecular diversity in this type of systems, we developed a strategy for synthesizing3,4‐dihydro‐1H‐pyrido[2,3‐e][1,4]diazepine‐2,5‐dione compounds starting from 2‐hydroxynicotinic acid and by using an Ugi reaction as a key step in the synthesis. We opted to use 2‐isocyanophenyl benzoate instead of Armstrong's convertible isocyanide in this multicomponent reaction. 3,4‐Dihydro‐1H‐pyrido[2,3‐e][1,4]diazepine‐2,5‐dione compounds were prepared by using an Ugi strategy starting from easily accessible materials (see scheme). 2‐Isocyanophenylbenzoate was used as the convertible isocyanide in this multicomponent reaction.