Access to 4-((Pyridin-2-yl)amino)quinazolinones via Annulation of 2-Aminobenzonitriles with <i>N</i>′-(Pyridin-2-yl)-<i>N</i>,<i>N</i>-dimethyl Ureas

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