9,10-methanoanthracene
Contents of Section
FR-8.4 Naming of bridged fused ring systems
FR-8.4.1 Order of citation of bridges
FR-8.4.2 Attachment locants
FR-8.4.3 Choice of attachment locants
FR-8.4.4 Treatment of identical bridges
FR-8.5 Bridged fused ring systems where replacement nomenclature is used
FR-8.6 Numbering of bridge atoms
FR-8.7 Order of numbering bridges
Continue with FR-9 Indicated Hydrogen
FR-8.4.1 Order of citation of bridges
If there is more than one bridge they are cited in alphabetical order unless one is dependent on another (see FR-8.7.a). In this case the dependent bridge is cited in front of all independent bridges. Identical bridges of the same order are quoted using the appropriate multiplicative prefix (see FR-8.4.4).
The fused ring system is numbered in the usual way (see FR-5).
a. Symmetric bridges
The locants of the positions on the fused ring system to which the bridge is attached are cited in numerical order in front of the bridge.
Example:
b. Asymmetric bridges
The locants of the positions on the fused ring system to which the bridge is attached are cited in the order implied by the name of the asymmetric bridge (locant order for the free valencies of the bridge is given by FR-8.3). If there is a choice, locants are cited in numerical order. See FR-9.3.2 for the use of indicated hydrogen.
Examples:
4a,8a-prop[1]enoquinoline
2H-5,3-(epoxymethano)furo[2,3-c]pyran
Beilstein name 2H-5,3-oxaethano-furo[3,4-b]pyran
10,5-[2,3]furanobenzo[g]quinoline
1-oxa-5,9,2-(ethane[1,1,2]triyl)cycloocta[1,2,3-cd]pentalene
FR-8.4.3 Choice of attachment locants
If there is a choice of attachment locants after the application of FR-8.4.2 preference is given in the following order:
a. The lowest set of locants for all the bridge attachment points considered as a set.
Examples:
5,8-epoxy-1,3-methanoanthracene
not 1,4-epoxy-5,7-methanoanthracene (1,3,5,8 preferred to 1,4,5,7)
b. Lowest locants in the order of citation for the bridges.
Example:
Note
CAS and Beilstein select when there is a choice of attachment locants those which result in lower numbers for heteroatoms in preference to the above criterion. (See FR-8.6 for numbering of bridge atoms.)
Examples:
1,4-epoxy-5,8-methanonaphthalene
CAS name 5,8-epoxy-1,4-methanonaphthalene
Beilstein name 5,8-epioxido-1,4-methano-naphthalene
1H-4,9-[2,3]thiophenobenzo[f]isoindole
CAS name 4,9[2',3']-thiopheno-1H-benz[f]isoindole
3H-4,9-[2,3]thiophenobenzo[f]isoindole
CAS name 4,9[3',2']-thiopheno-1H-benz[f]isoindole
Note
FR-8.4.4 Treatment of identical bridges
When there are two or more identical bridges this is indicated by the use of di-, tri-, etc. with single bridges (or bis-, tris- etc. with composite bridges or if di-, tri-, etc. would be ambiguous). The locants of the bridges are separated by a colon.
Examples:
FR-8.5 Bridged fused ring systems where replacement nomenclature is used
If the fused ring system can only be named using replacement nomenclature (see FR-7.1) any heteroatoms in a bridge are also named using replacement nomenclature. The replacement terms are cited in front of the name of the corresponding hydrocarbon bridged fused ring system.
Examples:
Note
FR-8.6 Numbering of bridge atoms
Bridge atoms are numbered continuing from the highest locant of the fused ring system. If there is more than one bridge atom (excluding hydrogen) the numbering starts at the chain end or ring atom connected to the bridgehead possessing the highest number. With a composite bridge each component of the composite bridge is completely numbered before the next component. If there is a choice of numbers then preference is given in the following order to:
a. low locants for heteroatoms
b. low locants for bridgehead atoms within a bridge
c. the remaining atoms (excluding hydrogen) being numbered continuously
Examples:
FR-8.7 Order of numbering bridges
a. Independent bridges are numbered before dependent bridges.
Example:
b. If there is more than one bridge of the same order preference is given to the bridge attached to the bridgehead with the higher locant at the first point of difference.
Examples:
c. If two bridges are attached to the same bridgehead atoms they are numbered in alphabetical order.
Examples:
Return to home page for Fused Ring Nomenclature.
1,4:5,8-dimethanonaphthalene
1,4:8,5-bis(epoxymethano)anthracene
Beilstein name 1,4;8,5-bis-oxaethano-anthracene
5,12:6,11-di[1,2]benzenodibenzo[a,e][8]annulene
CAS name 5,12[1',2']:6,11[1",2"]dibenzenodibenzo[a,e]cyclooctene
Beistein name 5,12:6,11-di-o-benzenodibenzo[a,e]cyclooctene
2,3,9-trioxa-5,8-methanocyclopenta[cd]azulene
CAS name 5,8-epoxy-2,3-dioxacyclopent[cd]azulene
Beilstein name 2,3-dioxa-5,8-epioxido-cyclopent[cd]azulene
1H-3,10-dioxa-2a1,5-ethanocycloocta[cd]pentalene
CAS name 4H-9,9b-(epoxymethano)-2-oxacycloocta[cd]pentalene
Beilstein name 8H-3,12-cyclo-furo[3',2':1,5]cyclopenta[1,2-c]oxonine
2H,5H-4,6,11-trioxa-1-thia-5,8b-[1,2]epicyclopentacyclopenta[cd]-s-indacene
CAS name 2H,5H-5,8b[2',3']-furano-4,6-dioxa-1-thiacyclopent[cd]-s-indacene
Beilstein name 2H,5H-4,6-dioxa-1-thia-5,8b-[2,3]furano-cyclopent[cd]-s-indacene
CAS and Beilstein use the appropriate bridge name which includes the heteroatom when replacement prefixes are needed to name the fused ring system. CAS cites the bridge prefixes before replacement prefixes, whereas Beilstein cites replacement prefixes before bridge prefixes.
1,4-ethanonaphthalene
9,10-[1,2]benzenoanthracene
10,5-[2,3]furanobenzo[g]quinoline
12H-5,10-[2,5]epipyranobenzo[g]quinoline
6,13-(methano[1,2]benzenomethano)pentacene
Beilstein name 1(1,2)-benzena-3(6,13)-pentacena-cyclobutaphane
6b,12b-[1,8]naphthalenoacenaphthyleno[1,2-a]acenaphthylene
13,16-epoxy-1,4:5,8-diepoxy-9,10-[1,2]benzenoanthracene
(13,16-epoxy is a dependant bridge) 
1,4-ethano-5,8-methanoanthracene
6,14:7,14-dimethanobenzo[7,8]cycloundeca[1,2-b]pyridine
6b,12a-([1,3][2]benzofurano)-7,12-epoxybenzo[k]fluoranthene
6,13-ethano-6,13-methanodibenzo[b,g][1,6]diazecine
Continue with FR-9 Indicated Hydrogen.