“…Oxazines [14] and quinazolines [15] are natural products which exhibit a widespread spectrum of biological activity including antitumor [16][17][18], antiinflammatory [19], and antiplatelet [20] properties. In view of these reports and as a continuation of our previous work on heterocyclic chemistry [21][22][23][24][25][26][27], we aimed to incorporate the pyrano moiety into the 1,5-position of oxazinone and pyrimidinone ring systems to obtain new heterocyclic system which is anticipated to possess notable chemical and pharmacological activities. So we utilized enaminonitrile in the synthesis of pyrano [2,3-d] [1,3]oxazin-5-one derivative and pyrano [2,3-d]pyrimidine and pyrano [2,3-d]pyrimidine-5-one derivatives in addition to studying their antioxidant activities.…”