Question

Assign the IUPAC name to \(\left[\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CH}\right]_{3} \mathrm{COH}\). (a) 3-(2-methylethyl)-3(1-methylethyl) pentan-2-ol (b) tris-(1-methylpropyl)methanol (c) 2, 4-dimethyl-3 (1-methylethyl) pentan- 2-ol (d) 3-(1-methylethyl)-2, 4-dimethylpentan-3-ol

Short answer

The correct IUPAC name is option (b): tris-(1-methylpropyl)methanol.

Step-by-step solution

Identify the Parent Chain

First, examine the given structure, \( [(\text{CH}_3)_2\text{CH}]_3\text{COH} \), to identify the longest continuous carbon chain, which contains the most carbon atoms and will act as the backbone for naming. In this case, the parent chain contains 5 carbon atoms, making it a pentane.

Identify Substituents on the Parent Chain

Next, identify the substituents attached to the main chain. The substituents in the given structure come from the \([-\text{C}(\text{CH}_3)_2\text{CH}]\) group, which is known as an "isopropyl" group. As there are three such groups, they are considered 'tris-1-methylethyl' substituents.

Identify the Functional Group and Position

Identify the functional group in the compound, which is the hydroxyl group \(-OH\). Determine its position on the parent chain. In this case, the \(-OH\) group is on the carbon connected to the three isopropyl groups, which is the central carbon of the longest carbon chain.

Combine the Elements

Combine the elements identified in the previous steps to form the full IUPAC name: The parent chain is 'pentane' and with the alcohol group, it becomes 'pentanol'. The complete name considering the substituents and the \(-OH\) group's position is 'tris-(1-methylpropyl)-methanol'.

Key concepts

Organic Chemistry

Organic chemistry is a branch of chemistry that primarily deals with the study of carbon-containing compounds. This field is diverse and extensive, as carbon forms the backbone of all organic molecules, the fundamental components of living organisms.
Within organic chemistry, we delve deeply into the various types of carbon structures and bonds. Carbon's ability to form four covalent bonds allows for a wide variety of compounds, including chains, rings, and networks.
Organic compounds can range from simple molecules like methane to complex proteins and can include other elements such as hydrogen, oxygen, nitrogen, and more. Organic chemistry plays a crucial role in understanding biochemical processes, developing pharmaceuticals, and creating new materials.

Functional Groups

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.
They are the "functional" parts of molecules that participate in chemical reactions. For instance, the carboxyl group COOH or the amino group NH2 are common functional groups.
Functional groups allow chemists to predict the reactivity and properties of compounds. Because similar functional groups behave similarly, they provide a convenient way to categorize different compounds. This is crucial in organic synthesis and in identifying components of natural products.

Hydroxyl Group -OH

The hydroxyl group, represented as OH, is a functional group consisting of an oxygen atom covalently bonded to a hydrogen atom. It’s a defining feature of alcohols and phenols.
The presence of a hydroxyl group in a compound can greatly influence its physical properties, such as solubility and boiling points, due to its ability to form hydrogen bonds.
In organic nomenclature, the position of the hydroxyl group is identified by numbering the carbon atom to which it is attached, ensuring that the lowest possible numbers are used in the compound's name. The presence of the -OH group in the IUPAC name is often indicated with the suffix '-ol'.

Isopropyl Group

The isopropyl group is a common structural motif in organic chemistry. Structurally, it consists of a central carbon atom bonded to two methyl groups (CH3) and one hydrogen (CH).
This group is derived from propane by removing one hydrogen atom from the central carbon atom, forming a branch in the carbon chain. Isopropyl groups are often used as substituents in larger molecules.
In chemical names, it is often referred to either as an "isopropyl" or "1-methylethyl" group. Identifying isopropyl groups is essential in IUPAC nomenclature as it's part of defining the principal chain and recognizing branching in the structure.

Carbon Chain Identification

One of the key steps in naming an organic compound according to IUPAC rules is identifying the principal carbon chain. This chain is the longest continuous chain of carbon atoms in the molecule and forms the basis for the compound's name.
Once the carbon backbone is identified, you can detect all other substituents or functional groups attached to it. The goal is to assign the lowest possible numbers to the substituents and the functional groups to create the most systematic name.
In complex structures, there can be multiple potential parent chains, but according to IUPAC rules, the chain with the most functional groups or highest priority features (like multiple bonds or hydroxyl groups) is selected.