A number of 4- substituted fluoranthenes have
been brominated to give monobromo derivatives.
and bromo-4- nitrofluoranthene.
The orientation of these compounds has been
elucidated and in each case the second substituent
has been shown to enter the 12- position. These conclusions
have been experimentally correlated with the
structure of 4:12 -diacetylfluoranthene. A straightforward synthesis of 6- bromo -2- nitrofluorenone has
also been accomplished.
Strong evidence has been produced to show that
contrary to previous belief disulphonation in
fluoranthene occurs at the 4:12 positions.
These results have been considered in the light
of the electronic theory of aromatic substitution,
and an explanation of 4:11 and 4:12 substitution has
been proposed. This explanation assumes the alteration
in balance of two contributing structures in the