The Foundations of Chemistry

derivatives of the corresponding carboxylic acids, the suffix -amidebeing substituted for

• ic acidor -oic acidin the name of the parent acid. The presence of alkyl or aryl substituents
  attached to nitrogen is designated by prefixing the letter Nand the name of the substituent
  to the name of the unsubstituted amide.

Proteins are complex amides of high molecular weight. Some synthetic fibers are also

polyamides (Sections 27-19 and 28-9).

Figure 27-19 Models of long-
chain fatty acids. The saturated fatty
acids (a) are linear and tend to pack
like sticks of wood to form solid
masses in blood vessels, thereby
constricting them. The trans
unsaturated fatty acids have a slight
Z-shaped kink in the chain, but are
also essentially linear molecules. By
contrast, cisunsaturated fatty acids
(b) are bent and so do not pack as
well as linear structures and do not
collect in blood vessels as readily.
Many natural vegetable fats and oils
contain esters of cisunsaturated fatty
acids, or polyunsaturated fatty acids.
Health problems associated with
saturated fatty acids can be decreased
by eating less animal fat, butter, and
lard. Problems due to transfatty
acids are reduced by avoiding
processed vegetable fats.

1082 CHAPTER 27: Organic Chemistry I: Formulas, Names, and Properties

O

CH 3 CNH 2 CNH 2

O

CH 3 C

CH 3

N CH 3

O

CH 3 C

H

N

O

N-phenylacetamide

(acetanilide)

acetamide benzamide N,N-dimethylacetamide

Crystals of the amide known as
acetaminophen (Tylenol) viewed
under polarized light. The structure
of acetaminophen is

C NOH

H

CH 3

O

(a) (b)

See the Saunders Interactive
General Chemistry CD-ROM,
Screen 11.8, Amino Acids and Proteins.