Chapter 18 Amines and Amides

Preparation of Amides Amides are prepared by heating a carboxylic acid with ammonia or an amine (1° or 2°).

Amides In amides, an amino group(–NH2) replaces the –OH group of carboxylic acids.

Guide to Naming Amides

Common Names of Amides In the common names of amides, replace the ic acid ending of the corresponding carboxylic acid with amide.

IUPAC Names of Amides 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

Examples of IUPAC and Common Names N-Methylethanamide (IUPAC) N-Methylacetamide (common) N-Ethylpropanamide (IUPAC) N-Ethylpropionamide (common)

Learning Check Write the IUPAC name for the following:

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

Aromatic Amides The amide of benzene is named benzamide.

Learning Check Draw the condensed structural formulas of: A. pentanamide B. N-methylbutyramide

Solution Draw the condensed structural formulas of: A. pentanamide B. N-methylbutyramide

Classification of Amides Amides are classified according to the number of carbon atoms bonded to the nitrogen atom. Primary (1°) amide Secondary (2°) amide Tertiary (3°) amide

Learning Check Give the common and IUPAC names for the following amides, and classify them as primary, secondary, or tertiary.

Solution Give the common and IUPAC names for the following amides, and classify them as primary, secondary, or tertiary. Butryamide (common) butanamide (IUPAC) primary (1°) N-Ethyl-N-methylacetamide (common) N-ethyl-N-methylethanamide (IUPAC), tertiary (3°)

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

Some Amides in Health and Medicine (continued)

Melting Points of 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

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