OZONATION OF BENZ[A]ANTHRACENE

The ozonation of benz[a]anthracene (I) has been studied in several different solvents. Attack at the bond of lowest bond-localization energy is the major reaction. The data strongly indicate 75 % attack at the bond of lowest bond-localization energy to give the expected acid IV and phthalic acid, 15% stepwise attack of 3 equiv of ozone at the atoms of lowest atom-localization energy to give quinone II and molecular oxygen, and 10 % addition of ozone at the atoms of lowest para-localization energy to give a transannular ozonide which decomposes to II and/or precursors of phthalic acid. A correlation of the three types of attack, based on differences in bond- and atom-, para- and bond-, and para- and atom-localization energies in a series of polycyclic aromatic hydrocarbons, is made. © 1968, American Chemical Society. All rights reserved.