Organic Chemistry

It is possible to selectively reduce just one of two nitro groups.

PROBLEM 5

Give the product of each of the following reactions:

a. c.

b. d.

PROBLEM 6 SOLVED

Show how the following compounds could be prepared from benzene:

a. benzaldehyde c. 1-bromo-2-phenylethane e. aniline

b. styrene d. 2-phenyl-1-ethanol f. benzoic acid

SOLUTION TO 6a

16.3 The Effect of Substituents on Reactivity

Like benzene, substituted benzenes undergo the five electrophilic aromatic substitu-
tion reactions discussed in Chapter 15 and listed in Section 16.2: halogenation, nitra-
tion, sulfonation, alkylation, and acylation. Now we need to find out whether a
substituted benzene is more reactive or less reactive than benzene itself. The answer

N

1. NBS/∆ /peroxide
   2. −C
   3. H 2 /Ni

CH 3

Na 2 Cr 2 O 7 , H+

∆

CH 3

CH 2 CH 3

1. NBS/∆/peroxide
   2. CH 3 O−

CH 3

Na 2 Cr 2 O 7 , H+

∆

CH 3

CHCH 3

(NH 4 ) 2 S

meta-dinitrobenzene

NO 2

NO 2

meta-nitroaniline

NO 2

NH 2

+ H 2

Pd/C

+ H 2 O

Sn, HCl HO−

+

NH 3

nitrobenzene protonated aniline

aniline

anilinium ion

NO 2

NO 2

NH 2

NH 2

Section 16.3 The Effect of Substituents on Reactivity 629

3-D Molecule:

Nitrobenzene

CH 3 Cl

AlCl 3

NBS, ∆

peroxide

CH 3

HO− MnO 2

∆

CH 2 OH C

O

H

CH 2 Br