Condensation of 5-nitroanthranilic acid (I) with formamidine hydrochloride (II) at 210 C generated the quinazolinone (III). Subsequent alkylation of (III) at the 3-N atom with ethyl 4-bromobutyrate (IV) in the presence of K2CO3 in DMF produced the quinazoline-3-butyrate ester (V). Finally, catalytic hydrogenation of the nitro group of (V) using Pd/C yielded the corresponding 6-aminoquinazoline.