IUPAC Nomenclature of Organic Compounds

What is IUPAC Nomenclature?

The IUPAC nomenclature of organic compounds refers to a systematic nomenclature of organic compounds as recommended by the International Union of Pure and Applied Chemistry (often abbreviated to IUPAC). It became necessary to adopt a systematic approach to organic compound nomenclature because of the sheer volume of new organic compounds discovered. However, IUPAC nomenclature guidelines are not always adhered to by chemists because some compounds have extremely long and tedious names as per the IUPAC nomenclature guidelines. 

IUPAC Nomenclature of Organic Chemistry

The International Union of Pure and Applied Chemistry (IUPAC) recommends the nomenclature IUPAC for organic chemical compounds in chemical nomenclature. Organic Chemistry Nomenclature is where it’s published. The ideal situation is for every possible organic compound to have a name that can be used to generate a structural formula. The IUPAC nomenclature is also used in inorganic chemistry. If you want to avoid long and tedious names in everyday communication, IUPAC’s official recommendations for naming a compound are not always followed in practice. For example, ethanol, as opposed to ethyl alcohol, is a more concise name for the same chemical compound. Non-systematic names that have to be memorized or sifted through can be more challenging to understand for molecules with simple structures. The common or trivial name, on the other hand, is often much shorter and clearer and thus preferred. Names that aren’t part of any system are frequently derived from a compound initial. In addition, long names may be more difficult to remember than simple structural formulas.

Organic Chemistry Nomenclature

Every object in this universe has a unique name that identifies it. However, it wasn’t until the early days of organic chemistry that compounds were named after their sources or the person who discovered them. These are known as “common or trivial” names.

IUPAC (the International Union of Pure and Applied Chemistry) has developed a set of nomenclature guidelines for organic compounds that are periodically updated. The stem name, prefix, and suffix make up the bulk of the IUPAC nomenclature for organic compounds. Although preferred IUPAC names are in use, other names can be used to take into account specific contexts or emphasize structural features common to a series of compounds. The “preferred IUPAC nomenclature” refers to the most commonly used IUPAC names. It is acceptable to use a name other than a preferred IUPAC name as long as it is unambiguous and follows IUPAC recommendations herein as a “general IUPAC name.”

Trivial Nomenclature System

Organic compound names are given non-systematic treatment in the Trivial Nomenclature system. There is no specific set of rules for writing the trivial naming of compounds. Instead, this system simplifies organic compound names. Toluene, phenol, and acetic acid are examples of this.

The IUPAC nomenclature of the same compounds is often much longer and more complicated than the trivial nomenclature of the same compounds. Because of this, this system is still relevant in the modern world.

The following is an example of the relative ease with which compounds can be named: According to the trivial system, tartaric acid is a carboxylic acid commonly found in tamarind. Therefore, 2,3-dihydroxy-1,4-butanedioic acid would be the IUPAC nomenclature for tartaric acid.

Drawbacks of the Trivial Nomenclature System

A few shortcomings of the trivial system for naming organic compounds are listed below.

• There may be multiple names for a single compound that are as meaningless as the compound itself. Phenol’s alternate names, such as hydroxybenzene and carbolic acid, serve as an excellent illustration of this concept in practice.
• Only a few compounds in each group can be named using the Trivial nomenclature system. There are many examples of this, such as formic and acetic acids being the first two members of the carboxylic acid group. However, there are no simple names for carboxylic acids with more atoms.
• Complex compounds in the trivial system do not have a set of guidelines for their name.

Nomenclature of Organic Compounds

A parent structure must be selected first and named before a systematic name for an organic compound can be formed. Prefixes, infixes, and, in the case of a parent hydride, suffixes can then be added to this basic name to convey the precise structural changes required to produce the compound in question from its parent structure. On the other hand, traditional names are widely used in both the business and academic worlds. Acetic acid, benzene, and pyridine are a few possible examples. Therefore, these traditional names are retained if they meet utility requirements and fit the general pattern of systematic nomenclature.

It’s a major new principle, and the concept of preferred IUPAC names is developed and applied systematically. Up to this point, the nomenclature developed and recommended by the IUPAC has stressed the generation of clear names in accordance with the historical progression of the subject. An international standard of language for patents, export regulations, environmental health and safety information, and other legal contexts became necessary in 1993 as the flow of information and human activity expanded across national boundaries.

Scope of Nomenclature for Organic Compounds

Compounds containing carbon as their primary element are referred to as organic compounds. Oxygen, hydrogen, and nitrogen are three of the most common functional or characteristic groups associated with carbon. Organic compounds’ basic core is completed by other elements, such as halogens and sulphur. Compounds containing this particular set of atoms were the first to be designated using substitutive nomenclature. All elements in Groups 14, 15, 16, 17 and Boron from Group 13  are able to use this nomenclature because of the success of this type of nomenclature.

IUPAC Nomenclature

According to the Guidelines set by IUPAC, the nomenclature of organic compounds must follow these steps:

1. There must be a naming convention for the parent hydrocarbon for the longest chain rule to apply: Straight carbon chains or chains with other shapes are generally considered the longest parent chains for the compound in question.
2. Locants in the Bottom Tier: The parent hydrocarbon chain’s carbon atoms must be numbered using natural numbers, starting at the end with the carbon atom carrying the lowest number.
3. Substitutes with the same name: Chemical prefixes that indicate how many times an organic compound has the same substituent are listed.
4. According to IUPAC nomenclature, organic compounds with multiple substituents are organized alphabetically by the names of their corresponding substituents in question.
5. Naming different substituents that occur in the same positions but with different names: Whenever two different substituent groups are present at the same position in an organic compound, the substituents are referred to by their alphabetical order.
6. If an organic compound has a branched structure, complex substituents must be referred to as substituted alkyl groups, and the carbon attached to them is numbered as one. The IUPAC nomenclature of the corresponding compounds must include these branched and complex substituents.

The format of the IUPAC Name of the Compound can be written as: Locant + Prefix + Root + Locant + Suffix. 

1. Root

Carbon atoms present in the compound’s longest carbon chain are represented by the number of atoms in the word root. As an example, ‘Meth’ refers to a carbon chain with one carbon atom, and ‘Pent’ refers to a carbon chain with five.

2. Suffix

In IUPAC nomenclature, a suffix is usually a functional group that follows the root of the name. In addition, there are the following subcategories.

• Alkanes are an example of a primary suffix, where the suffix ‘ane’ is written immediately after the root word.
• In writing, a secondary suffix comes after the primary suffix has been completed. Examples include alcohols (compounds with alkanes and alcohol groups attached) known as alkane-alcohols (compounds with an alkane and alcohol group attached).

A compound’s suffix can be written as part of the IUPAC name in accordance with these rules.

3. Prefix

The IUPAC nomenclature of a compound begins with a prefix and ends with a root. The presence of side chains or substituent groups in an organic molecule is indicated by prefixes, which are extremely helpful. Additionally, these prefixes reveal whether the compounds in question have a cyclic or acyclic nature or not.

Root Noun Phrase Indicate whether the given compound is cyclic or acyclic. For cyclic compounds, for example, the prefix ‘cyclo’ is used as a suffix.

To indicate side chains or substituent groups, secondary prefixes are used. The methyl group is an example of a prefix with this type of suffix.

Thus, prefixes in IUPAC nomenclature can be categorized into primary and secondary prefixes.

Conclusion

An effective nomenclature scheme accomplishes at least two goals. One of the most important things to include is information about the specific latticework of chains and rings used to connect the carbon atoms in the compound under consideration. The second step should identify and locate any functional groups in the compound. In most cases, the tetravalency of carbon can be used to determine the amount and location of hydrogen in organic compounds.

Organic chemists developed and used the IUPAC nomenclature system to avoid problems caused by arbitrary nomenclature. When given a structural formula and these rules, it should be possible to create a name for each compound. If you know the IUPAC name, you should be able to write the structural formula.