Rule A-34. Hydrocarbon Bridges (BRIDGED HYDROCARBONS)

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Bridged Hydrocarbons

Rule A-34. Hydrocarbon Bridges

34.1 - Polycyclic hydrocarbon systems which can be regarded as "ortho-fused" or "ortho- and peri-fused" systems according to Rule A-21 and which, at the same time, have other bridges

, are first named as "ortho-fused" or "ortho- and peri-fused" systems. The other bridges are then indicated by prefixes derived from the name of the corresponding hydrocarbon by replacing the final "-ane", "-ene", etc., by "-ano", "-eno", etc., and their positions are indicated by the points of attachment in the parent compound. If bridges of different types are present, they are cited in alphabetical order.

Examples of bridge names to Rule A-34.1

Butano

Benzeno (o-, m-, p-)

Ethano

Etheno

Methano

Propano

Examples to Rule A-34.1

34.2 - The parent "ortho-fused" or "ortho- and peri-fused" system is numbered as prescribed in Rule A-22. Where there is a choice, the position numbers of the bridgeheads should be as low as possible. The remaining bridges are then numbered in turn starting each time with the bridge atom next to the bridgehead possessing the highest number.

Example to Rule A-34.2

34.3 - When there is a choice of position numbers for the points of attachment for several individual bridges, the lowest numbers are assigned to the bridgeheads in the order of citation of the bridges and the bridge atoms are numbered according to the preceding rule.

Example to Rule A-34.3

34.4 - When the bridge is formed from a bivalent cyclic hydrocarbon radical, low numbers are given to the carbon atoms constituting the shorter bridge and numbering proceeds around the ring.

Examples to Rule A-34.4

34.5 - Names for radicals derived from the bridged hydrocarbons considered in Rule A-34.1 are constructed in accordance with the principles set forth in Rule A-24. The abbreviated radical names naphthyl, anthryl, phenanthryl, naphthylene, etc., permitted as exceptions to Rules A-24.2 and A-24.4, are replaced in such cases by the regularly formed names naphthalenyl, anthracenyl, phenanthrenyl, naphthalenediyl, etc.

Examples to Rule A-34.5

See Recommendations'93 R-2.4.1.2

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