Nomenclature substitutive

A substitutive name consists of the name of a parent hydride to which prefixes and suffixes are attached as necessary following the general pattern  

A given organic molecule is generally composed of a carbon skeleton and functional groups. A name matches a structure when the name of the parent hydride corresponds to the skeleton, while prefixes and sufiixes represent the functional groups and other structural characteristics, such as geometry. 

1 General. Alkanes are acyclic hydrocarbons of general formula C H2 + 2- The carbon 

2 Unbranched alkanes. Unbranched alkanes are also called normal alkanes. The names of the first four members of the homologous series of unbranched or normal alkanes, C H2 + 2 are retained names. They were coined more than 100 years ago, officially recognised by the Geneva Conference in 1892, and have been used ever since. There are no alternative names for them. 

However, higher members of the series are named systematically by combining the ending -ane, characteristic of the first four members and implying complete saturation, with a multiplicative prefix of the series penta-, hexa-, etc. of Table 4.2, which indicates the number of carbon atoms constituting the chain. The letter a , which ends the name of the multiplicative prefix, is elided. 

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. 

Whereas for most compound classes the exemplifications in Table 8 are directly applicable without any difficulty, the two alternative naming methods for aliphatic carboxylic acids and their derivatives as well as for nitriles and aldehydes require more detailed illustration. 

Carboxylic acids in the order -COOH, logues, then sulf(onic, inic)-, phosph(onic, ink)-, ars(onic inic)-acids Acid derivatives in the order anhydrides, esters, halides, amides, hydrazides, imides, amidines etc. 

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The lUPAC rules permit alkyl halides to be named m two different ways called func twnal class nomenclature and substitutive nomenclature In functional class nomencla ture the alkyl group and the halide (fluoride chloride bromide or iodide) are desig nated as separate words The alkyl group is named on the basis of its longest continuous chain beginning at the carbon to which the halogen is attached... 

Substitutive nomenclature of alkyl halides treats the halogen as a halo—(fluoro chloro bromo or lodo ) substituent on an alkane chain The carbon chain is numbered m the direction that gives the substituted carbon the lower number... 

Diols are almost always given substitutive lUPAC names As the name of the prod uct m the example indicates the substitutive nomenclature of diols is similar to that of alcohols The suffix dwl replaces ol and two locants one for each hydroxyl group are required Note that the final e of the parent alkane name is retained when the suffix begins with a consonant ( diol) but dropped when the suffix begins with a vowel ( ol)... 

Substitutive nomenclature (Section 4 2) Type of lUPAC nomenclature in which a substance is identified by a name ending in a suffix charactenstic of the type of compound 2 Methylbutanol 3 pentanone and 2 phenylpropanoic acid are examples of substitutive names... 

There are several types of nomenclature systems that are recognized. Which type to use is sometimes obvious from the nature of the compound. Substitutive nomenclature, in general, is preferred because of its broad applicability, but radicofunctional, additive, and replacement nomenclature systems are convenient in certain situations. 

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. 

Substitution means the replacement of one or more hydrogen atoms in a given compound by some other kind of atom or group of atoms, functional or nonfunctional. In substitutive nomenclature, each substituent is cited as either a prefix or a suffix to the name of the parent (or substituting radical) to which it is attached the latter is denoted the parent compound (or parent group if a radical). 

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 ... 

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

TABLE 1.8 Characteristic Groups Cited Only as Prefixes in Substitutive Nomenclature... 

Characteristic groups will now be treated briefly in order to expand the terse outline of substitutive nomenclature presented in Table 1.7. Alternative nomenclature will be indicated whenever desirable. 

Organic ring systems are named by replacement nomenclature. Three- to ten-membered mono-cyclic ring systems containing uncharged boron atoms may be named by the specialist nomenclature for heterocyclic systems. Organic derivatives are named as outlined for substitutive nomenclature. The complexity of boron nomenclature precludes additional details the text by Rigaudy and Klesney should be consulted. 

Ethers (R —O—R ). In substitutive nomenclature, one of the possible radicals, R—O—, is stated as the prefix to the parent compound that is senior from among R or R. Examples are methoxyethane for CH3OCH2CH3 and butoxyethanol for C4Hc,0CH2CH20H. 

Partial ethers of polyhydroxy compounds may be named (1) by substitutive nomenclature or (2) by stating the name of the polyhydroxy compound followed by the name of the etherifying radical(s) followed by the word ether. For example. 

Halogen Derivatives. Using substitutive nomenclature, names are formed by adding prefixes listed in Table 1.8 to the name of the parent compound. The prefix perhalo- implies the replacement of all hydrogen atoms by the particular halogen atoms. 

Ketenes. Derivatives of the compound ketene, CH2=C=0, are named by substitutive nomenclature. For example, C4Hc,CH=C=0 is butyl ketene. An acyl derivative, such as CH3CH2—CO—CH2CH=C=0, may be named as a polyketone, l-hexene-l,4-dione. Bisketene is used for two to avoid ambiguity with diketene (dimeric ketene). 

In order of decreasing priority for citation of a functional class name, and the prefix for substitutive nomenclature, are the following related compounds ... 

Substitution (see Seetion 1.02.9.1.1) is the formal proeedure most widely applied in modifying parent names. Indeed, the general term substitutive nomenclature is often used to describe the system of nomenclature in which substitution is the main operation. A fundamental concept of this system is that of the principal characteristic group . 

In substitutive nomenclature the use of the prefix oxo- or the suffix -one means the insertion of =0 in place of two hydrogen atoms. This is straightforward when the parent carries a CHz group at the appropriate position (example 206), but often the insertion of =0 requires prior reduction of a double bond. When the prefix oxo- is employed, this is achieved by using the appropriate hydro- prefix terms (example 207). However, the suffix -one can be used without hydro , the required reduction being implied rather than overtly stated (example 208) if desired the position of the hydrogen atom introduced to accommodate the carbonyl can be indicated in parentheses (see also examples 123 and 124). 

Alkylamines are nfflned in two ways. One method adds the ending -amine to the nfflne of the alkyl group. The other applies the principles of substitutive nomenclature by replacing the -e ending of an alkane name by -amine and uses appropr iate locants to identify the position of the fflnino group. Arylfflnines are nfflned as derivatives of aniline. 

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... 

IUPAC substitutive nomenclature locants, prefixes, parent compound, and one suffix. 

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