Transformations of 2-alkylamino-1,4-naphthoquinones under the action of nitrating mixture in acetic acid

Reactions of 2-alkylamino-1,4-naphthoquinones with a nitrating mixture in acetic acid afforded 2-alkyl-1-hydroxy-1H-naphtho[2,3-d]imidazole-4,9-diones.