1.2 Cyclic Systems
13
encountered. For more complex derivatives thereof, systematic names
should always be given preference.
~\
\ :
2
1
1.2
Cyclic Systems
1.2.1
Cyclic Hydrocarbon Systems
1.2.1.1
Monocyclic Hydrocarbons
2-Methylbutane-l,4-diyl
(2-Methyltetramethylene)
4- Propylpent-2-ene-l,S-diyl
(4-Propylpent -2-enylene)
Saturated and unsaturated monocyclic hydrocarbons are treated like their
acyclic analogues but with the specifying prefix cyclo in front of the name.
Monovalent substituent groups derived therefrom are again given the
ending ... yl, bivalent groups the ending ... diyl (formerly: ... ylene) when
different C atoms are involved and ... ylidene or ... l,l-diyl when the
free valences are at the same carbon atom. In numbering them, positions with free valences have precedence; only then are double and triple
bonds together and thereafter double bonds given the lowest locants
possible.
Cyclopropane
Cyclopent -2-enyl
H H
c=c
c~
3 'CH
III
II
C
lCH
, /
C-C
H2 H2
Cycloocta-l,3-dien-S-yne