Chemistry Reference
In-Depth Information
opposite sides of the double bond, is described as (
E
) (also from the
German,
entgegen
or opposite). Examples of (
Z
) and (
E
) isomers are shown
in Figure 4.16.
Cl
Cl
H
N
CH
3
H
3
C
N
CH
3
CH
3
Chloroamitriptyline
(
Z
) isomer
Chloroamitriptyline
(
E
) isomer
Figure 4.16
Examples of (Z) and (E) isomers.
It should be obvious that the
cis
isomer is
usually
also the (
Z
) isomer,
while the
trans
isomer is
usually
also the (
E
) isomer. This useful arrange-
ment is not foolproof, however, and the anticancer drug tamoxifen is a
notable example of a drug that is
trans
with respect to the phenyl groups,
but also (
Z
) when the Cahn-Ingold-Prelog priorities are used (Figure 4.17).
H
3
C
C
C
CH
3
N
O
CH
3
Figure 4.17
The structure of tamoxifen.
