One-step synthesis of alloxazines, alloxazine-5-oxides, 5-aryl-5-deazaalloxazines, and fervenulin-4-oxides

1-Methylalloxazines and 1-methylalloxazine-N-oxides were prepared by the treatment of 1-methyl-6-anilinouracils with diethyl azodiformate (DAD) and potassium nitrate, and sulfuric acid in acetic acid, respectively. In addition, 1-methyl-5-aryl-5-deazaalloxazines were prepared by refluxing of 1-methyl-6-anilinouracils with aryl aldehydes in acetic acid. Treatment of 6-benzylidenehydrazinouracils with potassium nitrate and sulfuric acid in acetic acid gave fervenulin-4-oxides.