Abstract
In conjunction with the anomalous behavior of 3-phenanthrol (1) in its bromination reactions as reported in the preceding paper, rearrangements of the 4-halogen substituent of (1) were investigated.Thus, 4, 9-dibromo-3-phenanthrol (3) was transformed rapidly into the 2, 9-di-bromo isomer (4) when heated in glacial acetic acid in the presence of hydrogen bromide. On the other hand, 4-chloro-3-phenanthrol (6) was converted only slowly into the 9-chloro isomer under similar conditions. In the former case, it was successful to isolate free bromine and 9-bromo-3-phenanthrol (2) from the reaction mixture as reaction intermediates suggesting an intermolecular rearrangement. It was also concluded that (3) and (4) were probably the "kinetically and thermody-namically controlled bromination products" of (2) respectively. Results were discussed in terms of steric hindrance at the 4-position.Preliminary results indicated that (3) was sensitive to alkali as well as to acid. Thus, when dissolved in a cold aqueous alkali-solution, it lost one of its bromine atoms to yield an alkali-insoluble matter.
