Organic Chemistry

028 CHAPTER 26 Lipids

26.11 Synthetic Steroids

The potent physiological effects of steroids led scientists, in their search for new

drugs, to synthesize steroids that are not available in nature and to investigate their

physiological effects. Stanozolol and Dianabol are drugs developed in this way. They

have the same muscle-building effect as testosterone. Steroids that aid in the develop-

ment of muscle are called anabolic steroids. These drugs are available by prescription

and are used to treat people suffering from traumas accompanied by muscle deteriora-

tion. The same drugs have been administered to athletes and racehorses to increase

their muscle mass. Stanozolol was the drug detected in several athletes in the 1988

Olympics. Anabolic steroids, when taken in relatively high dosages, have been found

to cause liver tumors, personality disorders, and testicular atrophy.

Many synthetic steroids have been found to be much more potent than natural

steroids. Norethindrone, for example, is better than progesterone in arresting ovula-

tion. Another synthetic steroid, RU 486, when taken along with prostaglandins, termi-

nates pregnancy within the first nine weeks of gestation. Notice that these oral

contraceptives have structures similar to that of progesterone.

norethindrone

H

H 3 C

O

H

RU 486

H

H

H 3 C

O

OH

C CCH 3

CH 3 N

CH 3

H

OH

CCH

H

stanozolol

H 3 C

H 3 C

H

Dianabol

H

H

H 3 C

O

H 3 C

OH

CH 3

H H

OH

CH 3

H

H

HN

N

Summary

Lipidsare organic compounds, found in living organisms,
that are soluble in nonpolar organic solvents. Fatty acids
are carboxylic acids with long hydrocarbon chains. Double
bonds in fatty acids have the cis configuration. Fatty acids
with more than one double bond are called polyunsatu-
rated fatty acids. Double bonds in naturally occurring un-
saturated fatty acids are separated by one methylene group.
Waxesare esters formed from long-chain carboxylic acids
and long-chain alcohols. Prostaglandinsare synthesized
from arachidonic acid and are responsible for regulating a
variety of physiological responses.
Triacylglycerols(triglycerides) are compounds in which
the three OH groups of glycerol are esterified with fatty acids.
Triacylglycerols that are solids or semisolids at room temper-

ature are called fats. Liquid triacylglycerols are called oils.

Some or all of the double bonds of polyunsaturated oils can be

reduced by catalytic hydrogenation. Phosphoacylglycerols

differ from triacylglycerols in that the terminal OH group of

glycerol is esterified with phosphoric acid instead of a fatty

acid. Phosphoacylglycerols form membranes by arranging

themselves in a lipid bilayer. Phospholipidsare lipids that

contain a phosphate group. Sphingolipids, also found in

membranes, contain sphingosine instead of glycerol.

Terpenescontain carbon atoms in multiples of 5. They

are made by joining together five-carbon isoprene units,

usually in a head-to-tail fashion—the isoprene rule.

Monoterpenes—terpenes with two isoprene units—have

10 carbons; sesquiterpeneshave 15. Squalene,a triterpene