Substituents functional groups nomenclature

A chemical name typically has four parts in the IUPAC system of nomenclature prefix, locant, parent, and suffix. The prefix specifies the location and identity of various substituent groups in the molecule, the locant gives the location of the primary functional group, the parent selects a main part of the molecule and tells how many carbon atoms are in that part, and the suffix identifies the primary functional group. 

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). 

IUPAC - standard guidelines for naming compounds Nomenclature Strategy - find longest carbon chain, identify and note location of functional groups and substituents by chain position number. 

Owing to the wide utility of the perfluoroalkyl chains (CH2)x(CF2)yF, the shortcut Rf>,hx has been introduced to symbolize these substituents in chemical formulae (Curran, 1996). For compounds with established acronyms, it has been proposed to use the prefix z-HxFy to designate a substituent of this type in z position relative to the main functional group (Kainz et al., 1997). Both types of nomenclatures will be used in this chapter if appropriate. 

For the nomenclature for ethers and alkyl halides the functional group is considered to be a substituent of the main alkane chain. The functional group is numbered and named as a substituent ... 

Many organic compounds contain more than one functional group. When one of those functional groups is halo (X-) or alkoxy (RO-), these groups are named as substituents as described in Sections 7.2 and 9.3B. To name other polyfunctional compounds, we must learn which functional group is assigned a higher priority in the rules of nomenclature. Two steps are usually needed ... 

III. Nomenclature of Molecules Containing Substituents and Functional Groups... 

Aromatic" compounds are those derived from benzene and similar ring systems. As with aliphatic nomenclature described above, the process is determining the root name of the parent ring determining priority, name, and position number of substituents and assembling the name in alphabetical order. Functional group priorities are the same in aliphatic and aromatic nomenclature. See p. 676 for the list of priorities. 

The term "heteroatom" applies to any atom other than carbon or hydrogen. It is common for heteroatoms to appear in locations that are inconvenient to name following basic rules, so a simple system called "replacement nomenclature" has been devised. The fundamental principle is to name a compound as if it contained only carbons in the skeleton, plus any functional groups or substituents, and then indicate which carbons are "replaced" by heteroatoms. The prefixes used to indicate these substitions are listed here in decreasing priority and listed in this order in the name ... 

Prostaglandins are also classified by the functional groups of the cyclopentane ring. The systematic nomenclature from prostanoic acid is straightforward, but for practical reasons the non-systematic use of capital letters to denote the ring substituents has become widely accepted. The structures of the cyclopentane ring... 

The lUPAC nomenclature for carboxylic acids uses the name of the alkane that corresponds to the longest continuous chain of carbon atoms. Tlie final -e in the alkane name is replaced by the suffix -oic acid. The chain is numbered, starting with the carboxyl carbon atom, to give positions of substituents along the chain. In naming, the carboxyl group takes priority over any of the functional groups discussed previously. 

Many different heteroatoms or functional groups may be attached to a benzene ring, and the presence of a certain functional group often imparts a unique name to that family of compounds. Perhaps the simplest heteroatom derivatives are halobenzenes such bromobenzene (18). The halogens do not constitute a formal functional group with respect to nomenclature, but rather are treated as substituents. Therefore, the halobenzenes are named fluorobenzene, chlorobenzene, bromobenzene, and iodobenzene. 

Alcohols are alkanols in lUPAC nomenclature. The stem containing the functional group gives the alcohol its name. AUcyl and halo substituents are added as prefixes. 

Because the steroid ring system is rigid, functional groups bonded to ring atoms have well-defined positions. Substituents below the plane of the ring are designated as a those above the plane of the ring are P. We recall that down and up in substituted cyclohexane compounds are not synonymous with equatorial and axial. For the same reasons, this method of nomenclature for steroids does not indicate whether the substituent is equatorial or axial. 

---