The product formed by the action of phenylhydrazine on 9, lO-phenanthrenequinone was first reported as the phenylhydrazone by Zincke, l and the analogous retenequinone compound was also reported as the phenylhydrazone by Bamberger and Grob. 2 “ Phenanthrenequinone phenylhydrazone” was later characterized by Auwed as an o- hydroxy azo compound on the basis of its chemical reactions, particularly those with acyl ...