The chemistry of heterocycles. IV. 2H‐pyrido[4,3‐e]‐1,3‐oxazine‐2,4(3H)‐dione, its precursors and some 3‐substituted derivatives.

The preparation of 2H‐pyrido[4, 3‐e]‐1, 3‐oxazine‐2, 4(3H)‐dione (II) and the anisoyl, benzoyl, 4‐chlorobenzoyl, trans‐cinnamoyl, 3, 5‐dinitrobenzoyl, 2‐furoyl, and 2‐naphthoyl derivatives substituted at position 3 of II together with their infrared and ultraviolet spectra are described. The 3‐substituted 2 and 4‐(2‐pyridylethyl) and hydroxymethyl derivatives of quinolinimide and cinchomeronimide were also prepared and their spectra recorded.