Substituent groups Substitutive nomenclature

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). 

These names are used in oi anic substitutive nomenclature for situations in which the substituent group is joined to the parent skeleton by a single element-carbon bond. 

The preferred names are also obtained by applying the principles of substitutive nomenclature. Substituents, considered as replacing hydrogen atoms, are named using prefixes of the appropriate group names and are cited, if there is more than one, in alphabetical order before the name of the parent hydride, using parentheses and multiplicative prefixes as necessary. 

A similar rule applies when citing names of substituent groups in substitutive nomenclature (see Section IR-6.3.1). 

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. 

Note that there is one general case where the word acid may appear in a fully systematic name of an inorganic compound, namely when substitutive nomenclature is used and prescribes a suffix for the highest ranking substituent group which ends with the word acid . 

Substitutive nomenclature (Section 4.3F) A system for naming compounds in which each atom or group, called a substituent, is cited as a prefix or suffix to a parent compound. In the lUPAC system only one group may be cited as a suffix. Locants (usually numbers) are used to tell where the group occurs. 

This naming method is used only for a limited number of compound classes which are listed in Table 9 in descending order of priority. In contrast to substitutive nomenclature, parent systems are named here in the guise of their radicals , i. e. substituent groups, to which are added, separated by a space, the anionized names of the compound class in question. Some examples may illustrate the principles of this nomenclature type ... 

Conjunctive nomenclature is particularly suitable for systems multiply substituted with identical functional parents but is generally used by Chem. Abstr. for any type of saturated linear monocarboxylic acid bearing a ring as substituent group. 

Alcohols and phenols are generally named by the substitutive method although Chem. Abstr. applies conjunctive nomenclature whenever possible, i.e. for chain alcohols with ring substituent groups... 

Note. In carbohydrate nomenclature, substitution at a heteroatom is normally indicated by citing the locant of the attached carbon atom, followed by a hyphen, and then the italicized heteroatom element symbol, e.g. 2-0-methyl, 5-N-acetyl. Substituents on the same kind of heteroatom are grouped (e.g. 2,3,4-tri-0-methy 1), and substituents of the same kind are cited in alphabetical order of heteroatoms (e.g. 5-N-acetyl-4,8,9-tri-0-acetyl). The alternative format with superscript numerical locants (e.g, N5,(/,(), ( -tetraacetyl), used in some other areas of natural product chemistry, is unusual in carbohydrate names. 

Simple phenolics are substituted phenols. The ortho, meta and para nomenclature refers to a 1,2-, 1,3- and 1,4-substitution pattern of the benzene ring, respectively, where in this case one of the functional groups is the hydroxyl group. With three functional groups, the substitution pattern can be 1,3,5, which, when all three substituents are identical, is designated as a mt /fl-tri-substitution pattern, whereas the 1,2,6, substitution pattern is indicated by the prefix v/c (Figure 1-1). 

The position of the substituents is given according to IUPAC nomenclature using the prefixes 1-, 3-, and 5-. Formazans unsubstituted in the 1- and 5-positions and 1,5-dialkyl-substituted formazans are unknown. Aryl or heteroaryl groups are the most common 1,5-substituents. The 3- or meso position can be occupied by a variety of substituents (e.g., aryl, heteroaryl, H, OH, SR, halogen, N02, CN, and alkyl). 

Calix[ ]arenes are a family of macrocycles prepared by condensation reactions between n /v/ra-substituted phenols and n formaldehyde molecules under either base or acid catalysis. Different sizes of the macrocycles can be obtained (n = 4-20) (Stewart and Gutsche, 1999) depending on the exact experimental conditions, which were mastered in the 1960 s (Gutsche, 1998), but the most common receptors are those with n =4,6,8 (macrocycles with an odd number of phenol units are more difficult to synthesize). We use here the simplified nomenclature in which the number of phenolic units is indicated between square brackets and para substituents are listed first.4 Calixarenes, which can be easily derivatized both on the para positions of the phenolic units and on the hydroxyl groups, have been primarily developed for catalytic processes and as biomimics, but it was soon realized that they can also easily encapsulate metal ions and the first complexes with d-transition metal ions were isolated in the mid-1980 s (Olmstead et al., 1985). Jack Harrowfield characterized the first lanthanide complex with a calixarene in 1987, a bimetallic europium complex with p-terf-butylcalix[8]arene (Furphy etal., 1987). 

Consider the two phenanthrene annulated NHC in Figure 1.26, they differ only in the position of the methyl group in the tolyl N-substituent. They have the same % value, but the o-tolyl substituted one is a monomeric NHC whereas the p-tolyl isomer is a dimeric tetraaminoethylene at ambient temperature [124], The A j, nomenclature is able to distinguish between the two and explain the monomeric or dimeric structure. The greater A value introduced by the < -methyl group is stericaUy active, whereas the greater A value introduced by the p-methyl group is sterically inactive. 

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