Chapter 14 Carboxylic Acids, Esters, Amines, and Amides 14.4 Amines

Amines Amines are derivatives of ammonia, NH3 contain N attached to one or more alkyl or aromatic groups CH3 CH3   CH3—NH2 CH3—NH CH3—N—CH3

Classification of Amines Amines are classified as primary, secondary, or tertiary: a primary (1) amine has one carbon group bonded to the nitrogen atom a secondary (2) amine has two carbon groups bonded to the nitrogen atom a tertiary (3) amine has three carbon groups bonded to the nitrogen atom H CH3 CH3 | | | CH3—N—H CH3—N—H CH3—N—CH3 1° 2° 3°

Skeletal Structures of Amines The skeletal structures show the shapes of amine molecules with one or more alkyl groups bonded to the nitrogen atom.

Naming Amines Simple amines are named as alkylamines list the names of the alkyl groups bonded to the N atom in alphabetical order in front of amine CH3—CH2—NH2 Ethylamine CH3—NH—CH3 Dimethylamine CH3 | CH3—N—CH2—CH3 Ethyldimethylamine

Learning Check Give the common name and classify as primary, secondary, or tertiary. A. CH3—CH2—CH2—NH2 CH3 | B. CH3—CH2—N—CH3

Solution A. CH3—CH2—CH2—NH2 propylamine, 1 CH3 | B. CH3—CH2—N—CH3 ethyldimethylamine, 3

Aromatic Amines The amine of benzene is named aniline. Alkyl groups on the N use the prefix N− with alkyl name. N-methylaniline aniline 3-chloroaniline

Learning Check Give the common name of each compound. A. CH3—NH—CH2—CH3 CH3 | B. CH3—CH2—N—CH2—CH3 C.

Solution Give the common name of each compound. A. CH3—NH—CH2—CH3 ethylmethylamine CH3 | B. CH3—CH2—N—CH2—CH3 C. diethylmethylamine aniline

Properties of Amines 1 and 2 amines can form hydrogen bonds with each other and water molecules can form hydrogen bonds, while amines with less than six carbons are soluble in water because they form hydrogen bonds with water 3 amines can only form hydrogen bonds with water molecules

Learning Check Consider the compounds below: 1. Which compound cannot form hydrogen bonds with other amines? 2. Which compound is not soluble in water? A. CH3—CH2—CH2—NH2 B. CH3—CH2—NH—CH3 C. CH3—CH2—CH2—CH3

Solution Consider the compounds below: 1. Which compound cannot form hydrogen bonds with other amines? CH3—CH2—CH2—CH3 C is an alkane, which cannot form hydrogen bonds with each other. 2. Which compound is not soluble in water? CH3—CH2—CH2—CH3 C is an alkane and therefore not soluble in water.

Amines React as Bases Like ammonia, amines are weak bases in water. NH3 + H2O NH4+ + OH– ammonium ion hydroxide ion CH3—NH2 + H2O CH3—NH3+ + OH– methylammonium ion hydroxide ion

Neutralization Forms Amine Salts An amine salt forms when amines such as those responsible the odor in fish are neutralized by acid such as citric acid in lemons is named by replacing the amine part of the name with ammonium, followed by the name of the negative ion

Neutralization Forms Amine Salts

Properties of Amine Salts Amine salts are solids at room temperature soluble in water and body fluids the form used for drugs

Alkaloids Alkaloids are physiologically active nitrogen- containing compounds produced by plants such as cocaine compounds that are alkali-like or have basic characteristics like amines used as anesthetics, as antidepressants, and in stimulants such as caffeine, and may be habit forming

Alkaloids: Cocaine Cocaine is extracted from plants by reacting them with hydrochloric acid and producing cocaine hydrochloride. When cocaine hydrochloride is treated with NaOH and ether it is called free-basing. This reaction produces “crack cocaine,” a free amine or free base of the amine.

Heterocyclic Amines A heterocyclic amine is a cyclic compound that contains one or more nitrogen atoms in a ring typically consists of five or six atoms in the ring with one or more nitrogen atoms

Caffeine Caffeine is a stimulant of the central nervous system is found in coffee beans, tea, chocolate, and soft drinks

Nicotine Nicotine increases the adrenaline level in the blood causes addiction to tobacco

Morphine and Codeine Morphine and codeine are alkaloids obtained from the oriental poppy plant used as painkillers modified to make heroin

Learning Check Write the structural formula for A. methylpropylamine B. 2-chloroaniline

Solution A. methylpropylamine CH3–CH2–CH2–NH–CH3 B. 2-chloroaniline