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

We have developed a convenient protocol for synthesizing N -(2-pyridyl)-substituted 4-(amino)quinazolin-2(1 H )-ones by reacting N , N -dimethyl- N '-pyridylureas with 2-aminobenzonitriles. The method relies on the ability of N , N -dimethyl- N '-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 H )-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%.