Application of anthranilic and dicarboxylic acids derivatives for building up a quinazolinone ring furnishes structures that open wide opportunities for constructing thereon new heterocyclic systems, in particular, those with fused heterocyclic rings [1]. The simplest methods suggested nowadays for the synthesis of compounds from the triazinoquinazolinone series are based mainly on the application as an initial substance of ethyl 3-amino-4-oxo-3,4-dihydroquinazoline- ...