Zinc triflate-catalyzed synthesis of pyrazino[2,1-b]quinazoline-3,6-diones

Using zinc triflate, the direct one-pot double cyclodehydration of linear tripeptides to the total synthesis of pyrazino2,1-b]quinazoline-3,6-diones (1a-l) on solid support was achieved with good overall yields in short reaction time. These syntheses of the pyrazino2,1-b]quinazoline-3,6-diones were conveniently achieved in only three steps, starting from the amino acid-bound Wang resin.