Synthesis of 2‑Amino-quinazolin-4(<i>3H</i>)‑ones Using 2‑Bromo‑<i>N</i>‑phenylbenzamide\nand Cyanamide Ullmann Cross-Coupling

Herein,\nan approach for synthesizing 2-amino-3-substituted quinoline-4(3<i>H</i>)-ones and <i>N</i>-phenylbenzamide derivatives\nwas developed. A series of quinoline-4(3<i>H</i>)-ones were\nsynthesized through Ullmann cross-coupling under air conditions using\ninexpensive, readily available cyanamide with 2-bromo-<i>N</i>-phenylbenzamide as the starting material, copper iodide as the catalyst,\nand potassium tert-butoxide as the base in dimethyl sulfoxide. Noteworthy\naspects of this method include its cost-effectiveness, the accessibility\nof raw materials, wide substrate applicability, ligand-free, open-air\nconditions, and simple operating procedures. Furthermore, investigations\nunder similar reaction conditions further show that substituting water,\nalcohols, phenols, amines, or mercaptans for cyanamide as the nucleophilic\nreagent can be used to prepare 2-functionalized <i>N</i>-phenylbenzamides.