Oxazines

Oxazines are heterocyclic compounds containing one oxygen and one nitrogen atom.

Many isomers exist depending on the relative position of the heteroatoms and relative position of the double bonds

By extension, the derivatives are also referred to as oxazines; examples include ifosfamide and morpholine (tetrahydro-1,4-oxazine). A commercially available dihydro-1,3-oxazine is a reagent in the Meyers synthesis for aldehydes. Fluorescent dyes such as Nile red and Nile blue are based on the aromatic benzophenoxazine.