Structures and Names of Amides 19.7 Hydrolysis of Amides Chapter 19 Amines and Amides

2 In amides, an amino group replaces the –OH group of carboxylic acids. O O || || CH 3 —C—OH CH 3 —C—NH 2 Amides

3 Preparation of Amides Amides are produced by reacting a carboxylic acid with ammonia or an amine (1° or 2°). O O   CH 3 —C—OH + NH 3 CH 3 —C—NH 2 + H 2 O O O   CH 3 —C—OH + CH 3 —NH 2 CH 3 —C—NH—CH 3 + H 2 O

4 Amides are named as alkanamides. In the IUPAC and common names, the –oic acid or -ic acid endings are replaced by –amide. O  Methanamide (IUPAC) H—C—NH 2 Formamide (common) O  Propanamide (IUPAC) CH 3 —CH 2 —C—NH 2 Propionamide (common) Naming Amides

5 An alkyl group bonded to the N atom is named as N-alkyl in front of the amide name. O  CH 3 —C—NH—CH 3 N-methylethanamide (IUPAC) N-methylacetamide (common) O CH 3   CH 3 —CH 2 —C—N—CH 3 N,N-dimethylpropanamide N,N-dimethylpropionamide Naming Amides with N Groups

6 Aromatic Amides The amide of benzene is named benzamide.

7 Classification of Amides Amides are classified according to the number of carbon atoms bonded to the nitrogen atom. O H || | CH 3 —C—N—H Primary (1°) amide O H || | CH 3 —C—N—CH 3 Secondary (2°) amide O CH 3 || | CH 3 —C—N—CH 3 Tertiary (3°) amide

8 Amides in Health and Medicine Urea is the end product of protein metabolism. Saccharin is an artificial sweetener. Some amides such as phenobarbital, Nembutal and Seconal are barbiturates. Acetaminophen is used to reduce fever and pain.

9 Amides in Health and Medicine

10 Physical Properties of Amides Hydrogen bonds form in primary and secondary amides, but not tertiary amides. The melting points of primary amides are higher than secondary amides, which have higher melting points than tertiary amides. All amides can form hydrogen bonds with water. Amides with 1-5 carbon atoms are soluble in water.

11 Hydrogen Bonding of Amides O || CH 3 —C—N—H | HHydrogen bonding occurs between primary amides. O || CH 3 —C—N—H | H

12 Amides undergo: Acid hydrolysis to produce a carboxylic acid and ammonium salt. Base hydrolysis to produce the salt of a carboxylic acid and an amine or ammonia. Reactions of Amides

13 acid hydrolysis O || O CH 3 —C—OH + NH 4 + Cl – || HCl + H 2 O CH 3 —C—NH 2 NaOH O || CH 3 —C—O – Na + + NH 3 base hydrolysis Hydrolysis Reactions