4-chloro anthranilic acid with ethyl chloro formate to get 7-chloro-1H-benzo[d][1,3]oxazine-2,4-dione (4- chloro isaticanhydride). A mixture of 4-chloro isatic anhydride, P-hydroxy aniline undergoes condensation with various aromatic aldehydes to give the products 7-chloro-3 hydroxy phenyl 3- substituted phenyl-2,3- dihydroquinazolin-4(1H)-one. The obtained product further condensed with amine to get the solid product of 3-hydroxy phenyl 3- substituted phenyl -7-amino- 2,3- dihydroquinazolin-4(1H)-one. The structures of these compounds were established on the basis of analytical and spectral data. All the newly synthesized compounds were evaluated for their anti-oxidant activities.