Chapter 26: Amides and Amines

Organic and Biochemistry Supplement to Enhanced Introductory College Chemistry

by Gregory Anderson; Jen Booth; Caryn Fahey; Adrienne Richards; Samantha Sullivan Sauer; and David Wegman

Chapter Contents

Except where otherwise noted, this OER is licensed under CC BY-NC-SA 4.0

Please visit the web version of Organic and Biochemistry Supplement to Enhanced Introductory College Chemistry to access the complete book, interactive activities and ancillary resources.

In this chapter, you will learn about:

  • Amines: what are they? What is their chemical structure? What are the physical and chemical properties of these nitrogen containing compounds?
  • Amides: what are they? What is their chemical structure? What are the physical and chemical properties of amides?

To better support your learning, you should be familiar with the following concepts before starting this chapter:

Variety of fish on ice at a fish market.
Figure 26.0a. The characteristic and unmistakable odour of fish is due to a mixture of simple alkylamines. (credit: Photo by Dudva, CC BY-SA 4.0)

By the end of this chapter, we will have seen all the common functional groups. Of those groups, carbonyl compounds and amines are the most abundant and have the richest chemistry. In addition to proteins and nucleic acids, the majority of pharmaceutical agents contain amine functional groups, and many of the common coenzymes necessary for biological catalysis are amines.

Amines are organic derivatives of ammonia in the same way that alcohols and ethers are organic derivatives of water. Like ammonia, amines contain a nitrogen atom with a lone pair of electrons, making amines both basic and nucleophilic.

Amines occur widely in all living organisms. Trimethylamine, for instance, occurs in animal tissues and is partially responsible for the distinctive odour of fish; nicotine is found in tobacco; and cocaine is a stimulant found in the leaves of the South American coca bush. In addition, amino acids are the building blocks from which all proteins are made, and cyclic amine bases are constituents of nucleic acids.

Spotlight on Everyday Chemistry: Hay Fever

Many everyday chemicals and medications rely on the amine and amide functional groups.  Infographic 26.0a. shows the applications of amines and amides to hay fever medication.

Infographic 26.0a.  Read more about “Hay Fever & Hay Fever Medications” by Andy Brunning / Compound Interest, CC BY-NC-ND, or access a text-based summary of infographic 26.0a [New tab].

Closely related to carboxylic acids and nitriles are the carboxylic acid derivatives, compounds in which an acyl group is bonded to an electronegative atom or substituent that can act as a leaving group in the nucleophilic acyl substitution reaction.

A chemical reaction shows the nucleophilic acyl substitution reaction of carboxylic acid derivative. The leaving group is denoted as Y.
Figure 26.0b. A nucleophilic acyl substitution reaction of carboxylic acid derivative. (credit: Organic Chemistry (OpenStax), CC BY-NC-SA 4.0)

Many kinds of acid derivatives are known, one of those being amides. Amides are common in both laboratory and biological chemistry. Amides are molecules that contain nitrogen atoms connected to the carbon atom of a carbonyl group.

This figure shows three structures. Two examples are provided. The basic structure has an H atom or R group bonded to a C atom which is double bonded to an O atom. The O atom as two sets of electron dots. The C atom is bonded to an N atom which in turn is bonded to two R groups or two H atoms. The N atom as one set of electron dots. The next structure includes acetamide, which has C H subscript 3 bonded to a C atom with a doubly bonded O atom. The second C atom is also bonded to N H subscript 2. Hexanamide has a hydrocarbon chain of length 6 involving all single bonds. The condensed structure is shown here. To the sixth C atom at the right end of the chain, an O atom is double bonded and an N H subscript 2 group is single bonded.
Figure 26.0c. The image represents the functional groups for amides. It also shows two specific examples of amides. (credit: Chemistry 2e (OpenStax),  CC BY 4.0)

Watch Amines: Crash Course Organic Chemistry #46 – Youtube (12 min)

Video Source: Crash Course Chemistry. (2022, February 16). Amines: Crash Course organic chemistry #46 [Video]. YouTube.

The table below outlines all organic compounds discussed thus far including their functional groups, formulas and names.

This table provides compound names, structures with functional groups in red, and examples that include formulas, structural formulas, ball-and-stick models, and names. Compound names include alkene, alkyne, alcohol, ether, aldehyde, ketone, carboxylic acid, ester, amine, and amide. Alkenes have a double bond. A formula is C subscript 2 H subscript 4 which is named ethene. The ball-and-stick model shows two black balls forming a double bond and each is bonded to two white balls. Alkynes have a triple bond. A formula is C subscript 2 H subscript 2 which is named ethyne. The ball-and-stick model shows two black balls with a triple bond between them each bonded to one white ball. Alcohols have an O H group. The O has two pairs of electron dots. A formula is C H subscript 3 C H subscript 2 O H which is named ethanol. The ball-and-stick model shows two black balls and one red ball bonded to each other with a single bond. There are four white balls visible. Ethers have an O atom in the structure between two R groups. The O atom has two sets of electron dots. A formula is ( C subscript 2 H subscript 5 ) subscript 2 O which is named ethanal. The ball-and-stick model shows two black balls bonded to a red ball which is bonded to two more black balls. All bonds are single. There are five white balls visible. Aldehydes have a C atom to which a double bonded O and an H and an R are included in the structure. The O atom has two sets of electron dots. A formula is C H subscript 3 C H O which is named Ethanal. The ball-and-stick model shows two black bonds bonded to two red balls. The ball-and-stick model shows two black balls bonded with a single bond and the second black ball forms a double bond with a red ball. There are three white balls visible. Ketones show a C atom to which a double bonded O is attached. The left side of the C atom is bonded to R and the right side is bonded to R prime. The O atom as two sets of electron dots. The formula is C H subscript 3 C O C H subscript 2 C H subscript 3 and is named methyl ethyl ketone. The ball-and-stick models shows four black balls all forming single bonds with each other. The second black ball forms a double bond with a red ball. There are five white balls visible. Carboxylic acids have a C to which a double bonded O and an O H are included in the structure. Each O atom has two sets of electron dots. A formula is C H subscript 3 C O O H which is named ethanoic or acetic acid. The ball-and-stick model shows two black balls and one red ball forming single bonds with each other. The second black ball also forms a double bond with another red ball. Three white balls are visible. Esters have a C atom which forms a double bond with an O atom and single bond with another O atom which has an attached hydrocarbon group in the structure. Each O atom has two sets of electron dots. A formula is C H subscript 3 C O subscript 2 C H subscript 2 C H subscript 3 which is named ethyl acetate. The ball-and-stick model shows two black balls, a red ball, and two more black balls forming single bonds with each other. The second black ball forms a double bond with another red ball. There are five white balls visible. Amines have an N atom in the structure to which three hydrocarbon groups, two hydrocarbon groups and one H atom, or one hydrocarbon group and two H atoms may be bonded. Each n has a single set of electron dots. A formula is C subscript 2 H subscript 5 N H subscript 2 which is named ethylamine. The ball-and-stick model shows two black balls and one blue ball forming single bonds with each other. There are five white balls visible. Amides have a C to which a double bonded O and single N incorporated in a structure between two hydrocarbon groups. One hydrocarbon group is bonded to the C, the other to the N. Amides can also have a H atom bonded to the N. The O atom as two sets of electron dots, and the N atom has one set. A formula is C H subscript 3 C O N H subscript 2 which is named ethanamide or acetamide. The ball-and-stick model shows two black balls and one blue ball forming single bonds with each other. The second black ball forms a double bond with one red ball. There are four white balls visible.
Figure 26.0d. Summary of Organic Compounds (credit: Chemistry 2e (OpenStax), CC BY 4.0)

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Organic and Biochemistry Supplement to Enhanced Introductory College Chemistry Copyright © 2024 by Gregory Anderson; Caryn Fahey; Adrienne Richards; Samantha Sullivan Sauer; David Wegman; and Jen Booth is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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