Facile Preparation of Tetrahydro-5H-pyrido[1,2,3-de]-1,4-benzoxazines via Reductive Cyclization of 2-(8-Quinolinyloxy)ethanones and Their Antioxidant Activity.

The radical scavenging activities of most of the title pyridobenzoxazines (II) (13 examples) are close to or even better than commercial standards ascorbic acid and BHT.