Y. Takemura et al., AZACRIDONE-A, THE 1ST NATURALLY-OCCURRING AZAACRIDONE ALKALOID FROM ACITRUS PLANT, Chemical and Pharmaceutical Bulletin, 41(4), 1993, pp. 789-790
Azacridone-A (1), the first naturally occurring azaacridone alkaloid,
was isolated from the roots of Marsh grapefruit (Citrus paradisi Macf.
), and its structure was determined by spectroscopic evidence.