Characteristic groups for substitutive nomenclature

TABLE 1.7 Characteristic Groups for Substitutive Nomenclature Continued)... 

IR-2.15.3.3 Ordering characteristic groups for substitutive nomenclature IR-2.15.3.4 Ordering ligands in formulae and names IR-2.15.3.5 Ordering components in salt formulae and names IR-2.15.3.6 Isotopic modification IR-2.15.3.7 Stereochemical priorities IR-2.15.3.8 Hierarchical ordering of punctuation marks IR-2.16 Final remarks IR-2.17 References... 

Table 8. Prefixes and suffixes for the most important characteristic groups in substitutive nomenclature... 

Substitutive Nomenclature. The first step is to determine the kind of characteristic (functional) group for use as the principal group of the parent compound. A characteristic group is a recognized combination of atoms that confers characteristic chemical properties on the molecule in which it occurs. Carbon-to-carbon unsaturation and heteroatoms in rings are considered nonfunctional for nomenclature purposes. 

In Table 1.8 are listed characteristic groups that are cited only as prefixes (never as suffixes) in substitutive nomenclature. The order of listing has no significance for nomenclature purposes. 

Systematic names formed by applying the principles of substitutive nomenclature are single words except for compounds named as acids. First one selects the parent compound, and thus the suffix, from the characteristic group listed earliest in Table 1.7. All remaining functional groups are handled as prefixes that precede, in alphabetical order, the parent name. Two examples may be helpful ... 

Compounds containing the neutral (formally zwitterionic) group =N2 attached by one atom to carbon are named by adding the prefix diazo- to the name of the parent compound (Rule 931.4), e.g., diazomethane, ethyl diazoacetate. Diazo is a so-called characteristic group appearing only as a prefix in substitutive nomenclature. Chemical Abstracts and Beilstein indexing of diazo compounds is analogous to that mentioned above for diazonium ions and salts, but Diazo compounds is not... 

An understanding of the concept of the principal characteristic group is vital for the correct application of substitutive nomenclature this will therefore be dealt with in some detail. 

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. 

In common nomenclature, alkynes are named as substituted acetylenes. The common name is obtained by citing the names of the alkyl groups, in alphabetical order, that have replaced the hydrogens of acetylene. Acetylene is an unfortunate common name for the smallest alkyne because its ene ending is characteristic of a double bond rather than a triple bond. 

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