Efficient microwave-assisted two-step procedure for the synthesis of 1,3-disubstituted-imidazo[1,5-a]quinazolin-5-(4H)-ones

A general method has been developed for the synthesis of 1,3-disubstituted-imidazo[1,5-a]quinazolin-5-(4H)-ones. This process involves initial microwave-assisted quinazolinone formation between anthranilamide and various Boc- or acylamino acids, followed by intramolecular cyclodehydration under acidic conditions. In the case of 3-monosubstituted-imidazoquinazolinones, the procedure needs the formation of the formamide derivatives by deprotection and formylation of the Boc-intermediates.