On the Reaction of 2-Benzylamino-1,4-naphthoquinones with Nitrosylsulfuric Acid

The reaction of 2-benzylamino-1,4-naphthoquinone with nitrosylsulfuric acid in acetic acid results in preferential formation of 2,1- and 2,3-heterocyclization products: (E)-4-(hydroxyimino)-2-phenylnaphtho [2,1-d]oxazol-5(4H)-one and 2-phenyl-1-hydroxy-1H-naphtho[2,3-d]imidazole-4,9-dione. In addition, 2-phenylnaphtho[2,1-d]oxazol-4,5-dione and N-(3-nitro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)benzamide are also formed. The reaction of 2-benzylamino-3-chloro-1,4-naphthoquinone with nitrosylsulfuric acid in acetic acid gives 3-diazonapthalene-1,2,4(3H)-trione and benzaldehyde.