Question

Combine the proper prefix, infix, and suffix and write the IUPAC name for each compound. (a) \(\mathrm{CH}_{3} \mathrm{CCH}_{3}\) (b) \(\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{3} \mathrm{CH}\) (c) OC1CCCC1 (d) C1=CCCCCC1

Short answer

Question: Name each compound using IUPAC nomenclature rules: (a) \(\mathrm{CH}_{3} \mathrm{CCH}_{3}\) (b) \(\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{3} \mathrm{CH}\) (c) OC1CCCC1 (d) C1=CCCCCC1 Answer: (a) Ethyne (b) Pentane (c) Cyclopentanol (d) Cycloheptatriene

Step-by-step solution

Identify functional groups and the parent chain for each compound.

Since IUPAC nomenclature is based on the longest continuous carbon chain containing the highest order functional group, begin by finding the parent chain for each compound. (a) \(\mathrm{CH}_{3} \mathrm{CCH}_{3}\): The parent chain is a two-carbon chain with a triple bond. (b) \(\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{3} \mathrm{CH}\): The parent chain is a five-carbon chain with no double or triple bonds. (c) OC1CCCC1: This compound is cyclopentanol, a cyclic compound with a five-carbon chain with an alcohol functional group. (d) C1=CCCCCC1: This compound is cycloheptatriene, a cyclic compound with a seven-carbon chain with three double bonds.

Name each compound using IUPAC nomenclature rules.

Now that we have identified the parent chain and functional groups for each compound, we can apply the IUPAC rules to name each compound. (a) \(\mathrm{CH}_{3} \mathrm{CCH}_{3}\): The two-carbon chain with a triple bond is named ethyne. (b) \(\mathrm{CH}_{3}\left(\mathrm{CH}_{2}\right)_{3} \mathrm{CH}\): The five-carbon chain with no double or triple bonds is named pentane. (c) OC1CCCC1: The five-carbon cyclic compound with an alcohol functional group is named cyclopentanol. (d) C1=CCCCCC1: The seven-carbon cyclic compound with three double bonds is named cycloheptatriene. The IUPAC names of the compounds are: (a) Ethyne (b) Pentane (c) Cyclopentanol (d) Cycloheptatriene

Key concepts

Organic Chemistry Naming

Understanding the International Union of Pure and Applied Chemistry (IUPAC) naming system is critical for students studying organic chemistry. The IUPAC system provides a standardized way to name chemical compounds to ensure clarity and uniformity across the scientific community. The naming process involves several steps, starting with the identification of the longest carbon chain, which serves as the compound's skeleton and is referred to as the parent chain. This chain's length determines the base name of the compound, with prefixes such as meth-, eth-, prop-, etc., denoting the number of carbon atoms.

Once the parent chain is identified, the next step is to locate and name functional groups - the parts of the molecule responsible for its chemical reactions. Functional groups are prioritized in naming based on a hierarchy, with some groups taking precedence over others in the compound's name. Multiple functional groups or other substituents are named using prefixes in alphabetical order before the base name. For example, a molecule with both an alcohol and a methyl group would be named with the prefix 'methyl' followed by the functional group name, like in 'methyl alcohol'.

Besides, double and triple bonds have infixes such as '-ene' and '-yne' respectively, that are included in the compound's name directly after the base name of the carbon chain. Thus, a good grasp of the IUPAC rules enables students to systematically break down a compound's structure and arrive at a unique name that accurately describes its chemical makeup.

Chemical Compound Classification

Chemical compounds can be classified in several ways, and such classification is pivotal in organic chemistry. Organic compounds are primarily categorized based on the type of functional group(s) they contain. These functional groups determine the chemical properties and reactivity patterns of the compounds. Categories include alcohols, aldehydes, ketones, carboxylic acids, esters, amines, and many others.

Moreover, compounds can be subdivided into classes like alkanes, alkenes, and alkynes based on the presence of carbon-carbon single, double, or triple bonds. Cyclic compounds form another category, in which carbons are arranged in rings rather than straight chains. For instance, cycloalkanes are ring structures with single bonds, while arenes contain aromatic rings. Distinguishing between these types can significantly help students in predicting the behavior of compounds during chemical reactions, understanding their physical properties, and assisting with their proper naming according to IUPAC conventions.

Functional Groups

In organic chemistry, functional groups are the key to understanding the vast array of molecules and their chemistry. These specific groups of atoms within molecules are responsible for characteristic reactions and properties. Some common functional groups include hydroxyl groups in alcohols (-OH), carboxyl groups in carboxylic acids (-COOH), carbonyl groups in ketones (-CO-) and aldehydes (-CHO), and amino groups in amines (-NH2).

Each functional group is associated with specific reactivity patterns and can be transformed through chemical reactions. For instance, the hydroxyl group makes alcohols polar and capable of engaging in hydrogen bonding, affecting their boiling points and solubility. Learning to recognize these groups and understand their influence on a molecule's behavior is an essential skill in organic chemistry. It provides the basis for predicting the outcome of chemical reactions, anticipating molecular interactions, and, as seen in the exercise, is central to the IUPAC naming convention.