Question

Name each of the following compounds: (a) ${\mathrm{CH}}_3-\mathrm{O}-{\mathrm{CH}}_2-\mathrm{CH}{\left({\mathrm{CH}}_3\right)}_2$ (b) ${\left({\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\right)}_2-\mathrm{O}$ (c) $\left({\mathrm{CH}}_3\right){}_2\mathrm{CH}-\mathrm{O}-{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_3$ (d) ${\mathrm{CH}}_3-\mathrm{O}-{\mathrm{CH}}_2{\mathrm{CH}}_2-\mathrm{O}-{\mathrm{CH}}_3$ (e) ${\mathrm{CH}}_3{\mathrm{CH}}_2-\mathrm{O}-{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2-\mathrm{OH}$ (f) CC(Cl)CC1CO1

Short answer

The short versions of the compound names are: (a) Methyl isopropyl ether (b) Dipropyl ether (c) Isopropyl butyl ether (d) 1,2-Dimethoxyethane (e) 2-Methoxymethylpentan-1-ol (f) 3-(1,3-Dioxolanyl)-2-chloropropane

Step-by-step solution

Compound (a): Identify functional group and main carbon chain

In the compound ${\mathrm{CH}}_3-\mathrm{O}-{\mathrm{CH}}_2-\mathrm{CH}{\left({\mathrm{CH}}_3\right)}_2$, the functional group is an ether (R-O-R'). The main carbon chain has three carbon atoms: ${\mathrm{CH}}_2\mathrm{CH}{\left({\mathrm{CH}}_3\right)}_2$.

Compound (a): Naming

The ether has two substituents, a methyl group (CH3) and an isopropyl group (CH(CH3)2). In alphabetical order, the molecule is called "methyl isopropyl ether."

Compound (b): Identify functional group and main carbon chain

In the compound $\left(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2}\right)_{2}-\mathrm{O}$, the functional group is also an ether. Both substituents are the same and consist of propyl groups (CH3CH2CH2).

Compound (b): Naming

Since both substituents are the same, the molecule is called "dipropyl ether."

Compound (c): Identify functional group and main carbon chain

In the compound $\left(\mathrm{CH}_{3}\right){ }_{2} \mathrm{CH}-\mathrm{O}-\mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}$, the functional group is again an ether. The substituents of the ether are an isopropyl group (CH(CH3)2) and a butyl group (CH2CH2CH2CH3).

Compound (c): Naming

Following alphabetical order, the molecule is called "isopropyl butyl ether."

Compound (d): Identify functional group and main carbon chain

In the compound $\mathrm{CH}_{3}-\mathrm{O}-\mathrm{CH}_{2} \mathrm{CH}_{2}-\mathrm{O}-\mathrm{CH}_{3}$, we have two ether functional groups. The molecule is symmetric, with both substituents being methoxy groups (CH3O).

Compound (d): Naming

The carbon backbone is an ethane (CH2CH2) with two methoxy groups attached, one on each carbon. Thus, the molecule is called "1,2-dimethoxyethane."

Compound (e): Identify functional group and main carbon chain

In the compound $\mathrm{CH}_{3} \mathrm{CH}_{2}-\mathrm{O}-\mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2}-\mathrm{OH}$, there is both an ether and an alcohol functional group. We will focus on the main carbon chain containing the alcohol hydroxyl (-OH) group, which is a pentane (CH3CH2CH2CH2OH).

Compound (e): Naming

We have a pentan-1-ol with an ether functional group inserted on its second carbon atom in the form of a methoxymethylene (OCH2) group. The molecule is called "2-methoxymethylpentan-1-ol."

Compound (f): Identify functional group and main carbon chain

The compound with the SMILES representation "CC(Cl)CC1CO1" contains the following functional groups: a halogen group (chlorine) and an ether group as a ring structure. The main carbon chain has three carbon atoms (propyl).

Compound (f): Naming

The molecule is a propyl group with one chlorine attached to the second carbon (2-chloropropyl). Moreover, there is a five-membered ring ether (1,3-dioxolane) attached to the third carbon. Thus, the molecule can be named "3-(1,3-dioxolanyl)-2-chloropropane."

Key concepts

Ether Functional Group

In organic chemistry, the ether functional group is represented by the oxygen atom connected to two alkyl or aryl groups (R-O-R'). They are known for their characteristic resistance to reactivity and their role as solvents in chemical reactions. Ethers can be symmetrical, where both alkyl groups are the same, like dipropyl ether, or asymmetrical, as seen in methyl isopropyl ether. Ethers are named by listing the alkyl groups in alphabetical order followed by the word 'ether'.

For instance, ethoxyethane (diethyl ether) is a common ether where two ethyl groups are attached to an oxygen atom. This simplicity in structure leads to a correspondingly straightforward naming convention, invaluable for students mastering organic chemistry nomenclature.

Alcohol Functional Group

The alcohol functional group consists of a hydroxyl (-OH) bonded to a carbon atom. In alcohols, the carbon to which the -OH group is attached can be primary, secondary, or tertiary, influencing the molecule's properties and reactivity. For naming, the suffix '-ol' is used with the parent alkane's name, indicating the presence of an alcohol group.

An example would be naming a five-carbon alcohol chain with a hydroxyl group on the first carbon as 'pentan-1-ol.' If an alcohol also contains an ether group, like in 2-methoxymethylpentan-1-ol, the molecule is named considering both functional groups, with the alcohol group typically taking precedence in the naming hierarchy.

Halogenated Organic Compounds

A halogenated organic compound is one that includes one or more halogen atoms (fluorine, chlorine, bromine, iodine) bonded to the carbon skeleton. These compounds often possess unique physical and chemical properties due to the electronegative nature of the halogens. When naming these compounds, the prefix 'fluoro-', 'chloro-', 'bromo-', or 'iodo-' is used alongside the number indicating the carbon atom's position to which the halogen is attached.

For instance, a propyl chain with a chlorine on the second carbon is termed '2-chloropropane.' In compounds with multiple functional groups, the halogen's nomenclature is integrated with other substitutive or functional nomenclature rules.

Organic Chemistry Nomenclature

Navigating the organic chemistry nomenclature requires an understanding of various rules set out by the International Union of Pure and Applied Chemistry (IUPAC). These rules prioritize the identification of the main carbon chain, substituents, and functional groups. The nomenclature system allows chemists to deduce the structure of a compound from its name and vice versa. Steps often include finding the longest carbon chain, naming substituents, identifying functional groups, and assembling the name with appropriate prefixes, infixes, and suffixes.

The order for naming a compound is determined by the functional group's priority, the alphabetical order of substituents, and the locants that provide the smallest numbers to the substituents and functional groups. Compounds can also have multiple functional groups, as seen in the example '2-methoxymethylpentan-1-ol,' where both ether and alcohol functional groups are present.

SMILES Notation

The SMILES notation (Simplified Molecular Input Line Entry System) is a way to represent a chemical structure using a line of characters. This notation is highly valued in computational chemistry for its ease in rendering molecules on digital platforms. It employs a series of codes and symbols to indicate atoms, bonds, and ring structures without the need for 2D or 3D graphics.

For example, the SMILES string 'CC(Cl)CC1CO1' encodes a structure that features a propyl chain with a chlorine atom and an ether in a five-membered ring. Understanding SMILES allows students and professionals to quickly exchange complex structural information and supports the efficient management of chemical databases.