One of the most important features in 4H-3,1-benzoxazinones chemistry is their use as key starting materials for further transformations in design and synthesis of biologically active compound [1,2]. Quinazolinediones are versatile intermediates in the synthesis of heterocycles with high pharmacological [3] and biological [4] activities. Owing to the potent activity of quinazolinediones, considerable attention has been focused on their synthesis [5]. Herein, an expedient method for the synthesis of the title compounds is described. The reaction of 2-ethoxycarbonylbenzoxazin-4-ones 1 with 1,2-phenylenediamine in PEG leads to the desired compounds quinazolin-6,12-diones 2 (Scheme 1). Good to high yields of 2 are obtained under mild reaction conditions with easy work-up.
