Access to 4-((Pyridin-2-yl)amino)quinazolinones via Annulation of 2-Aminobenzonitriles with '-(Pyridin-2-yl)-,-dimethyl Ureas.

We have developed a convenient protocol for synthesizing -(2-pyridyl)-substituted 4-(amino)quinazolin-2(1)-ones by reacting ,-dimethyl-'-pyridylureas with 2-aminobenzonitriles. The method relies on the ability of ,-dimethyl-'-pyridyl/quinolinyl ureas to act as masked isocyanates under thermal activation, followed by a Dimroth rearrangement of 4-imino-3-(hetaryl)-3,4-dihydroquinazolin-2(1)-ones. Conducted at 120 °C, either in DMF or under solvent-free conditions, this approach has produced 28 derivatives of 4-aminoquinazolinones, featuring pyridine or quinoline substituents, with yields of up to 92%.