Abstract:
The work described in t his thesis was initiated with
the intention of exploring new routes for the synthesis of
certain 4, 5-disubstituted phenanthrenes. A series of reactions
have been investigated in detail and several 4, 5-disubstituted
phenanthrenes have been prepared. Some of the methods employed
were novel and the yields of products were comparable or even
better than the existing routes .
A major observation made during the course of this
work was the stability of the seven-membered ring system
bridging the 4 and 5 positions of the phenanthrene nucleus .
It has been found t hat the unbridged structures are not preferred
if the compound is capable of isomerising to a bridged form .
We have explained this phenomenon in t erms of the stereochemistry
of t he 4 and 5 positions of the phenanthrene nucleus
as well as the geometry of the bridge .
Low temperature NMR studies have been carried out to
investigate the conformations of the benzylic hydrogens of
some of the 4,5-bridged compounds. However, the results were
not conclusive as more than one reason could be attributed
t o the observations .
