Organic Chemistry

732 CHAPTER 18 Carbonyl Compounds II

In ketosis, a pathological condition that can occur in people with diabetes, the body

produces more acetoacetate than can be metabolized. The excess acetoacetate breaks

down to acetone—a ketone—and Ketosis can be recognized by the smell of ace-

tone on a person’s breath.

Two ketones that are of biological importance illustrate how a small difference in

structure can be responsible for a large difference in biological activity: Progesterone

is a female sex hormone synthesized primarily in the ovaries, whereas testosterone is a

male sex hormone synthesized primarily in the testes.

18.1 Nomenclature

Aldehydes

The systematic name of an aldehyde is obtained by replacing the terminal “e”from the

name of the parent hydrocarbon with “al.”For example, a one-carbon aldehyde is

methanal; a two-carbon aldehyde is ethanal. The position of the carbonyl carbon does

not have to be designated, because it is always at the end of the parent hydrocarbon

and therefore always has the 1-position.

The common name of an aldehyde is the same as the common name of the corre-

sponding carboxylic acid (Section 17.1), except that “aldehyde”is substituted for “ic

acid”(or “oic acid”). When common names are used, the position of a substituent is

designated by a lowercase Greek letter. The carbonyl carbon is not designated; the car-

bon adjacent to the carbonyl carbon is the

HH H H

systematic name:common name: formaldehydemethanal Br

CH 3

ethanal

acetaldehyde

CH 3 CH

2-bromopropanal

-bromopropionaldehyde

C

O

C

O

C

O

a-carbon.

progesterone

a female sex hormone

C O

H 3 CH

H

OO

H H H

CH 3

CH 3

testosterone

a male sex hormone

OH

H 3 CH

CH 3

acetoacetate acetone

CH 3 CH 2 O− CH 3 CH 3

C + CO 2

O

C

O

C

O

CO 2.

vanillin

vanilla flavoring

cinnamaldehyde

cinnamon flavoring

O

C

H

HO

CH CHCH

O CH 3

H 3 CCH 2

OCH 3

(R)-(−)-carvone

spearmint oil

O

C

H 3 CCH 2

C

CH 3

(S)-(+)-carvone

caraway seed oil

O

O

CH 3

H 3 C CH 3

camphor