Reactions of 2-amino-4H-1-benzopyran-4-one with 4-oxo-4H-1-benzopyran-3-carbaldehydes

The title aldehyde 1 reacts smoothly with the enamine moiety of 2-aminochromone 2 to produce hitherto unreported 3 -(2-hydroxybenzoy1)-5H-1-benzopyrano [2,3-blpyridin-5-one (azaxanthone) 5. This reaction has been extended for the synthesis of bisazaxanthone 9.