The cyclization of 2-amino-5-iodobenzoic acid (I) with an excess of refluxing trifluoroacetic anhydride (II) by means of triethylamine gives 6-iodo-2-(trifluoromethyl)-3,1-benzoxazin-4-one (III), which is treated with conc. aqueous NH4OH to afford 6-iodo-2-(trifluoromethyl)quinazolin-4(3H)-one (IV). The reaction of (IV) with refluxing POCl3 yields 4-chloro-6-iodo-2-(trifluoromethyl)quinazoline (V), which is finally condensed with 1-Ethylpiperidine-3-amine (VI) by means of triethylamine in ether.