Amines and Amides

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Amines and Amides

• Module 13

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Amines 1

• Amines are organic molecules that are similar to
  NH3 (ammonia), except that at least one of the
  hydrogen atoms in NH3 (ammonia) is replaced by a
  carbon atom
• If one of the hydrogen atoms is replaced, the
  amine is primary (1)
• If two of the hydrogen atoms are replaced, the
  amine is secondary (2)
• If all three of the hydrogen atoms are replaced,
  the amine is tertiary (3)

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Amines 2

• Like ammonia, amines are weak bases
• Also like ammonia, amines have a lone electron
  pair, which can accept a hydrogen ion
• When amines accept a hydrogen ion from water,
  hydroxide ions are released

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Naming Amines

• Identify the carbon-containing groups attached to
  the nitrogen atom
• List the carbon-containing groups in alphabetical
  order and follow them by amine

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Example 1 of Naming Amines

• Problem Name this amine and classify it
• Branches ethyl and propyl
• Alphabetize ethylpropyl
• Name ethylpropylamine
• Classification Secondary (2º) Amine

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Example 2 of Naming Amines

• Problem Name this amine and classify it
• Branches two ethyl
• Alphabetize diethyl
• Name diethylamine
• Classification Secondary (2º) Amine

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Reactions of Amines

• Amines react with water to produce an ammonium
  ion and a hydroxide ion

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An Example of Reactions of Amines

• Problem What is the product of the above
  reaction?
• The amine gains a hydrogen from the water, and
  the hydroxide ion from the water is released
• See above for products

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Amides

• Amides are considered to be amine derivatives of
  carboxylic acids i.e. one of the carbons
  connected to the nitrogen contains a double bond
  to an oxygen atom
• They are neutral compounds
• They do not affect the pH of an aqueous system
  since they do not accept hydrogens (like amines)
  or give hydrogens
• Amides are the essential link for amino acids in
  protein molecules
• The amide functional group is called a peptide
  linkage when it is in a protein molecule

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Reactions of Amides

• Amides react with water to produce a carboxylic
  acid and an amine
• This reaction is referred to as the hydrolysis of
  amides
• This reaction is catalyzed by addition of heat
  and either an acid or a base
• In the humans, this reaction is catalyzed by
  enzymes rather than by an acid or a base due to
  the fact that humans must maintain a constant
  body temperature and a pH close to neutral

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An Example of Reactions of Amides

• Problem What is the product of the above
  reaction?
• Steps to the hydrolysis of an amide
• Break the bond between the nitrogen (N) and the
  carbonyl (CO) group
• Add a hydrogen (from the water) to the nitrogen
  and add a OH (from the water) to the carbon of
  the carbonyl group
• See above for the products

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Drawing a Structure From a Name

• Steps
• Draw the branches around the nitrogen
• Add hydrogens to the nitrogen so that it has 3
  bonds

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Two Examples of Drawing an Amine From Its Name
propylamine AND butyldimethylamine