22
1 Parent Structures
from the sequence of letters! If several attached (secondary) components
are present alphabetical order is valid as usual.
In order to find the correct sequences of letters and numbers for both
the individual components and the final assembly of a fused system it
is imperative to follow a series of orientation rules as outlined in the
following.
First of all, a uniform graphical representation of all the rings involved
in the construction of a fused assembly must be decided upon as shown
below:
D
o
o
o
Vertically drawn bonds must be distanced as far as possible from each
other; this is of particular significance for higher membered rings, e. g.:
4
not
4
not
The formulae are subsequently oriented in such a way that:
a) as many rings as possible are positioned on a horizontal axis,
b) as many rings as possible occur in the upper right quadrant,
c) as few rings as possible are placed in the lower left quadrant,
d) as many rings as possible are situated above the horizontal axis,
e) the priority of numbering is guaranteed.