Characteristic groups expressed prefixes

Table 6. Characteristic groups expressed as prefixes only...

Steroids are compounds possessing the tetracyclic skeleton of cyclopenta[a]phenan-threne (1) or a skeleton derived therefrom by one or more bond scissions or ring expansions or contractions. Natural steroids have trivial names. The nomenclature of steroids is not based on these trivial names, but on a few stereoparent hydrides that are common to many compounds. Substitutive nomenclature is used to designate characteristic groups and unsaturation. Structural modifications are expressed by appropriate non-detachable prefixes. 

Radicofunctional Nomenclature. The procedures of radicofunctional nomenclature are identical with those of substitutive nomenclature except that suffixes are never used. Instead, the functional class name (Table 1.9) of the compound is expressed as one word and the remainder of the molecule as another that precedes the class name. When the functional class name refers to a characteristic group that is bivalent, the two radicals attached to it are each named, and when different, they are written as separate words arranged in alphabetical order. When a compound contains more than one kind of group listed in Table 1.9, that kind is cited as the functional group or class name that occurs higher in the table, all others being expressed as prefixes. 

According to this preferred type of nomenclature appropriately tailored morphems for substituent and characteristic groups are attached as prefixes or suffixes to the stem (parent) name. The substituents specified in Table 6, however, are exclusively expressed as prefixes. In the same way, substituting hydrocarbon and heterocyclic parent structures are prefixed in the form of their group names. 

All other characteristic groups can be named both as prefixes and/or as suffixes. The most senior characteristic group is expressed as suffix and... 

The manner in which characteristic groups pertaining to the compound classes listed in Table 7 are to be expressed in the form of prefixes and suffixes is shown in Table 8. 

It is important to note that multiplying prefixes have no influence on the alphabetical order of prefixes. The names of substituted substituents are alphabetized as a whole otherwise such substituent groups are subject to the same rules as are applied to parent structures, with two exceptions a) even high-ranked characteristic groups are expressed as suffixes here and b) the linking position (free valence) has the lowest possible locant within the limitations put forth in Section 6.4. For chain substituents this is traditionally always locant 1. 

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