6-Hydroxy-7-methoxy-4(1H)-quinazolinone is a reactant used in the preparation of 4-anilinoquinazoline derivatives that have shown antitumor activities. 6-Hydroxy-7-methoxy-4(1H)-quinazolinone was also used as a reactant in the synthetic preparation of 2-arylbenzothiazoles as kinase inhibitors.