1,2-Naphthoquinone → Benzo[a]phenazine-11-carboxylic acid

Participants

Reaction Steps

A mixture of 1,2-naphthoquinone (commercially available, 2.0 g) and 2,3-diamino-benzoic acid, diacetate salt, (3.79 g) was heated to reflux in acetic acid (30 mL) for 2 hours. The reaction mixture was cooled and the solvent removed in vacuo to yield a gum. This was purified using flash chromatography to yield a 2:1 mixture of the desired title compound to the undesired benzo[a]phenazine-8-carboxylic acid (840 mg). The two isomers were separated after further modification (see Reference Example 3B below).

Provenance & Evidence