18.5 Amides - PowerPoint Presentation

Slide1

18.5 Amides

Tylenol, an aspirin substitute, contains acetaminophen. Acetaminophen is an amide; it acts to reduce fever and pain; however, it has little anti-inflammatory effect.

Learning Goal Draw the amide product from amidation, and give the IUPAC and common names.Slide2

Preparation of Amides

Amides

are derivatives of carboxylic acids in which a nitrogen group (—NH2) of a primary or secondary amine replaces the hydroxyl (—OH)

group of carboxylic acids.

Core Chemistry Skill

Forming AmidesSlide3

Preparation of Amides

Amides are produced

in a reaction called amidation or condensation.when a carboxylic acid reacts with ammonia or a primary or secondary amine and heat.

Amide production is accompanied by the production of water. Slide4

Study Check

Predict the products of the following

amidation reaction:Slide5

Solution

Predict the products of the following

amidation reaction:Slide6

Naming Amides

In both the common and IUPAC names, amides are named by dropping the

oic acid (IUPAC) or ic acid (common) from the carboxylic acid name and adding the suffix

amide.Alkyl groups attached to the nitrogen of an amide are named with the prefix N

followed by the

alkyl name.Slide7

Guide to Naming AmidesSlide8

Naming Amides

Give the IUPAC name for the following amide:

STEP 1

Replace

oic

acid (IUPAC) or ic acid common) in the carboxyl name with amide. butanamide

ANALYZE Given Need

THE

amide IUPAC name

PROBLEM

Slide9

Naming Amides

Give the IUPAC name for the following amide:

STEP 2 Name each substituent on the N atom using

the prefix

N

and the alkyl name.

N-methylbutanamideSlide10

Study Check

Give the IUPAC and common names for the following amides:

A.

B. Slide11

Study Check

Give the IUPAC and common names for the following amides:

A.

B.

ethanamide

(IUPAC)

acetamide

(common)

N

-

ethylpropanamide

(IUPAC)

N

-

ethylpropionamide

(common)Slide12

Physical Properties of Amides

Amides do not have the properties of bases seen in amines.

Only methanamide is a liquid at room temperature, while other amides are solids. Primary (1°) amides have the highest melting points because the the —NH2 group can form the most hydrogen bonds. Melting points of the secondary (2

°) amides are lower because they form fewer hydrogen bonds. Tertiary (3°)

amides

cannot form hydrogen bonds; they have the lowest melting points (see Table 18.3).Slide13

H-Bonding in 1° Amides

Primary

(1°) amides, can formhydrogen bonds with the –NH2 group of other amideshydrogen bonds with water molecules making them soluble in water as long as they have less than five

carbonsSlide14

H-Bonding in 2°

Amides

Secondary (2°) amides have lower melting points because they form fewer hydrogen bonds with other amides.form hydrogen bonds with water molecules, making them soluble in water as long as they have fewer than five carbons.Slide15

H-Bonding in 3°

Amides

Tertiary (3°) amides have the lowest melting points because they form the fewest hydrogen bonds.can only form one hydrogen bond with H2

O.Slide16

Urea

is the simplest natural amide. the end product of protein metabolism in the body.

excreted in the urine.If the kidneys malfunction, urea is not removed and builds to a toxic level, a condition called

uremia.

Chemistry Link to Health:

Amides and MedicineSlide17

Aspirin substitutes

contain phenacetin and acetaminophen.act to reduce fever and pain but have little anti-inflammatory effect.

Chemistry Link to Health:

Amides and MedicineSlide18

Many

barbituates are cyclic amides of

barbituric acid. act as sedatives in small doses or sleep inducers in large doses.are habit forming.

Barbiturate drugs include phenobarbital (Luminal) and pentobarbital (Nembutal).

Chemistry Link to Health:

Amides and Medicine