Bromination of 9-Phenanthrol

Abstract

9-Phenanthrol had been known to give the 10-substituted compounds on the electro-philic substitutions. In this paper the second site of bromination of[1]was established as follows. Dibromo-9-phenanthrol, obtained by bromination of[1]in CS2, was converted to bromo-9-phenanthrol[4]by reduction with Zn/AcOH.[4]was converted to dibromophenanthrene[6]by Bucherer's reaction followed by a modified Sandmeyer's reaction as shown in Scheme (1). Compound[6]was identified as 3, .6-dibromophenanthrene by comparison with an authentic specimen obtained from 9-bromo-3-phenanthrol. Accor-dingly, the second bromination of[1]is revealed to occur at the 3-position.