1.2 Cyclic Systems
67
If whole heterocyclic systems appear as bridges they are treated like analogous carbocyclic bridges.
18
4,9-Dihydro-4,9- [2' ,3'] thiophenonaphtho[2,3-c]furan
13H-13,6-[2,3]Furanomethanodibenzo [b,i] acridine
If replacement nomenclature has to be applied for a fused assembly, upon
which a bridged system is based, the same holds for the bridges.
4
5
5,7 -Dihydro-4H-10-oxa-9-thia-1,8b,P-diphospha7,8b: 4,8b-dimethanocyclopenta[ de] naphthalene
Concerning the selection of parent structures for bridged systems, special
attention must be paid to a really serious discrepency between the current
IUPAC recommendations and Chern. Abstr. practice: according to IUPAC
the base component should have the smallest number of hetero atoms
while Chern. Abstr. gives precedence to the one with the largest number.
OQ)
IUPAC: 1,2,3,4-Tetrahydro1,3-epoxynaphthalene
0C9
Chern. Abstr.: 3,4-Dihydro-1 ,3-methano-1H -2-benzopyran