Fundamental Principles Of Naming

Organic Compound Nomenclature

A systematic name for an organic compound is formed by first selecting and then identifying a parent structure. This basic name is then supplemented by prefixes, infixes, and, in the case of a parent hydride, suffixes that indicate the structural modifications required to form the compound in question from the parent structure. In contrast to such systematic names, traditional names are frequently employed in both industry and academia. Acetic acid, benzene, and pyridine are a few examples. As a result, when they match the utility requirements and fit into the general pattern of systematic nomenclature, these traditional names are kept.

A key new idea is developed, and the concept of preferred IUPAC names is devised and implemented consistently. 

The Scope of Organic Compound Nomenclature

All compounds with carbon as the primary constituent are classed as organic compounds for naming purposes. The three elements that are frequently coupled with carbon to form the system of functional or characteristic groups are oxygen, hydrogen, and nitrogen. Other elements, such as halogens and sulphur, round out the fundamental core of elements found in organic molecules. Substitutive nomenclature was originally used to describe compounds with this set of atoms. This style of nomenclature was so successful that it was extended to all elements of Groups 14, 15, 16, 17, and boron in Group 13; it might be extended to all elements of Group 13.

Nomenclature according to IUPAC 

The following stages must be followed for compound nomenclature, according to the IUPAC Guidelines:

1.The Longest Chain Rule states that the parent hydrocarbon must be identified and named. The parent chain of the molecule in question is usually the longest chain of carbon atoms, whether it is a straight chain or any other structure.

2.The Locants with the Fewest Numbers: The carbon atoms in the parent hydrocarbon chain must be numbered using natural numbers, commencing at the end, with the lowest number allocated to the carbon atom carrying the substituents.

3.Several occurrences of the same substituent: Prefixes such as di, tri, and so on are used to indicate the total amount of the same substituent in the supplied chemical compounds.

4.Naming of distinct substituents: In organic compounds with several substituents, the corresponding substituents are listed alphabetically in the IUPAC nomenclature of the organic compound in issue.

The name of various substituents found in the same positions: When two different substituent groups exist in the same location in an organic compound, the substituents are called in ascending alphabetical order.

Complex Substitutes: Complex substituents of organic compounds with branched structures must be identified as substituted alkyl groups, with one carbon connected to the substituent group. In the IUPAC nomenclature of the related compounds, these branching and complicated substituents must be written in brackets.

The IUPAC Name of the Compound can be written in the following format:

1.The root

The word root denotes the total number of carbon atoms contained in the compound’s longest carbon chain. For example, ‘Meth’ denotes a chain with one carbon atom while ‘Pent’ denotes a chain with five carbon atoms.

2.Suffixes

In IUPAC nomenclature, the suffix is usually a functional group belonging to the molecule that follows the root of the name. It is further subdivided into the following categories.

a)A Primary Suffix is one that is written right after the word root, like in the instance of alkanes, where the suffix is ‘ane.’

b)A Secondary Suffix is a suffix that is usually written after the primary suffix. Compounds containing an alkane and an alcohol group attached, for example, are referred to as alkanols, with ‘ol’ being the secondary suffix for the alcohol group.

According to these standards, a compound’s suffix can be written as part of the IUPAC name of the provided compound.

3.The prefix

In IUPAC nomenclature, prefixes are added before the root of the compound. Prefixes are extremely valuable since they indicate the presence of side chains or substituent groups in an organic compound. These prefixes also reveal whether the chemicals in issue are cyclic or acyclic.

Primary prefixes indicate whether a compound is cyclic or acyclic. For cyclic compounds, for example, the prefix ‘cyclo’ is employed.

Side chains or substituent groups are indicated by secondary prefixes. The ‘CH3‘ group, often known as the methyl group, is an example of this type of prefix.

Thus, in IUPAC nomenclature, prefixes are generically classed as primary prefixes and secondary prefixes.

Conclusion

A nomenclature scheme that can be used to name fundamental organic compounds. It occasionally fails with increasingly complicated molecules, in which case formal or (better still) IUPAC nomenclature is preferred. When all carbons form a continuous, unbranched (linear) chain, the “n-” (or normal) prefix is appended.