The cyclization of 4,5-dimethoxyanthranilic acid (I) with formamide by heating at 190 C gives 6,7-dimethoxyquinazoline (II), which is treated with refluxing SOCl2 to yield 4-chloro-6,7-dimethoxyquinazoline (III). Finally, this compound is condensed with 3-aminophenol (IV) in refluxing THF.