Organic Chemistry

CONTROLLING FLEAS

Several different drugs have been developed

to help pet owners control fleas. One of these

drugs is lufenuron, the active ingredient in Program.

Lufenuron interferes with the production of chitin. Since

the exoskeleton of a flea is composed primarily of chitin, a

flea cannot live if it cannot make chitin.

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Section 22.19 Some Naturally Occurring Products Derived from Carbohydrates 949

PROBLEM 27

What is the main structural difference between

a. amylose and cellulose? c. amylopectin and glycogen?

b. amylose and amylopectin? d. cellulose and chitin?

(^1) In referring to the sugar found in DNA, it is called 2-deoxyribose. In numbering the sugar in a DNA
molecule, it is because the nonprimed numbers refer to positions on the heterocyclic
amine components.
2 ¿-deoxyribose
22.19 Some Naturally Occurring Products
Derived from Carbohydrates
Deoxy sugarsare sugars in which one of the OH groups is replaced by a hydrogen
(deoxymeans “without oxygen”). 2-Deoxyribose—it is missing the oxygen at the C-2
position—is an important example of a deoxy sugar. Ribose is the sugar component of
ribonucleic acid (RNA), whereas 2-deoxyribose is the sugar component of deoxyri-
bonucleic acid (DNA). RNA and DNA are N-glycosides—their subunits consist of an
amine bonded to the of the anomeric carbon of ribose or 2-deoxyribose.
The subunits are linked by a phosphate group between C-3 of one sugar and C-5 of the
next sugar (Section 27.1).^1
3
5
a heterocyclic
amino base
O
OOH
O N
OOP −
O
O
O OH
N
OOP −
O
O
O OH
N
a short segment of RNA
the sugar component is D-ribose
O
O
O N
OOP −
O
O
O
N
OOP −
O
O
O
N
a short segment of DNA
the sugar component is D-2′-deoxyribose
b-position
F
F
Cl
Cl
C
O
C
O O
F F
CF 3
F
NN
HH
lufenuron