Locants derived substituent groups

Radicals from Ring Systems. Univalent substituent groups derived from polycyclic hydrocarbons are named by changing the final e of the hydrocarbon name to -yl. The carbon atoms having free valences are given locants as low as possible consistent with the fixed numbering of the... 

Substitutive nomenclature is a system in which names are based on the names of parent hydrides, which define a standard population of hydrogen atoms attached to a skeletal structure. Names of derivatives of the parent hydrides are formed by citing prefixes or suffixes appropriate to the substituent groups (or substituents) replacing the hydrogen atoms (preceded by locants when required), joined without a break to the name of the unsubstituted parent hydride. 

Substituents replacing the hydrogen atom of an alcoholic hydroxy group of a saccharide or saccharide derivative are denoted as O-substituents. The 0- locant is not repeated for multiple replacements by the same atom or group. Number locants are used as necessary to specify the positions of substituents they are not required for compounds fully substituted by identical groups. Alternative periphrase names for esters, ethers, etc. may be useful for indexing purposes. For cyclic acetals see 2-Carb-28. 

Cyclic acetals formed by the reaction of saccharides or saccharide derivatives with aldehydes or ketones are named in accordance with 2-Carb-24.1, bivalent substituent names (formed by general organic nomenclature principles) being used as prefixes. In indicating more than one cyclic acetal grouping of the same kind, the appropriate pairs of locants are separated typographically when the exact placement of the acetal groups is known. 

Metallocene derivatives may be named by either standard organic suffix (functional)7 or prefix nomenclature. Substituents are given the lowest numerical locants in the usual manner on the equivalent cyclopentadienyl rings of the ocene entity. The first ring is numbered 1 to 5 and the second ring is numbered V to 5. In metallocenes composed of multiple ocene groupings the cyclopentadienyl rings are further numbered 1" to 5", V" to 5", etc. The radical names -ocenyl, -ocenediyl, -ocenetriyl, etc. are used. For examples see Table 25. 

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