Synthesis of 4-Arylaminoquinazolines and 2-Aryl-4-arylaminoquinazolines from 2-Aminobenzonitrile, Anilines and Formic Acid or Benzaldehydes

2-Aminobenzonitrile treated with anilines in the presence of aluminium chloride gave respective 2-amino-N-arylbenzamidines. 4-Arylaminoquinazolines lacking a substituent at the 2 position were obtained directly by heating 2-amino-N-arylbenzamidines in formic acid; in similar conditions other carboxylic acids did not react with the amidines. The latter when treated with aldehydes afforded 2-aryl-4-arylimino-1H-2,3-dihydroquinazolines readily oxidizable by potassium permanganate to 2-aryl-4-arylaminoquinazolines.