1. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.1 18.4 Amides Chapter 18 Amines and Amides

2. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.2 Preparation of Amides Amides are prepared by heating a carboxylic acid with ammonia or an amine (1° or 2°).

3. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.3 In amides, an amino group(–NH 2 ) replaces the –OH group of carboxylic acids. Amides

4. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Guide to Naming Amides 4

5. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.5 In the common names of amides, replace the ic acid ending of the corresponding carboxylic acid with amide. Common Names of Amides

6. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.6 Write the IUPAC name for STEP 1 Identify the corresponding carboxylic acid. butanoic acid STEP 2 Replace oic acid with amide. butanamide STEP 3 Name a substituent on the N atom using the prefix N- and the substituent name. N-methylbutanamide IUPAC Names of Amides

7. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.7 N-Methylethanamide (IUPAC) N-Methylacetamide (common) Examples of IUPAC and Common Names N-Ethylpropanamide (IUPAC) N-Ethylpropionamide (common)

8. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.8 Learning Check Write the IUPAC name for the following:

9. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.9 Solution STEP 1 Identify the corresponding carboxylic acid. pentanoic acid STEP 2 Replace oic acid with amide. pentanamide STEP 3 Name substituents on the N atom using the prefix N- and their names. N,N-diethylpentanamide

10. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.10 Aromatic Amides  The amide of benzene is named benzamide.

11. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.11 Learning Check Draw the condensed structural formulas of: A. pentanamide B. N-methylbutyramide

12. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.12 Solution Draw the condensed structural formulas of: A. pentanamide B. N-methylbutyramide

13. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.13 Classification of Amides  Amides are classified according to the number of carbon atoms bonded to the nitrogen atom. Tertiary (3°) amide Secondary (2°) amide Primary (1°) amide

14. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.14 Give the common and IUPAC names for the following amides, and classify them as primary, secondary, or tertiary. Learning Check

15. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.15 Give the common and IUPAC names for the following amides, and classify them as primary, secondary, or tertiary. Solution Butryamide (common) butanamide (IUPAC) primary (1°) N-Ethyl-N-methylacetamide (common) N-ethyl-N-methylethanamide (IUPAC), tertiary (3°)

16. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.16 Some Amides in Health and Medicine Amides found in health and medicine include the following:  urea, the end product of protein metabolism  saccharin, an artificial sweetener  barbituarates, such as phenobarbital, Nembutal, and Seconal  acetaminophen, used to reduce fever and pain

17. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.17 Some Amides in Health and Medicine (continued)

18. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.18 Melting Points of Amides Amides  that are primary and secondary form hydrogen bonds and have high melting points  that are tertiary (no H on N) do not form hydrogen bonds and have lower melting points

19. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Solubility of Amides in Water Primary, secondary, and tertiary amides with 1 to 5 carbon atoms  form hydrogen bonds with water  are soluble in water 19