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Prévia do material em texto

CHAPTER 18 665 
 
18.41. 
(a) The reagents indicate a nitration reaction, so we 
must decide where the nitro group will be installed. The 
aromatic ring has one substituent (Br) which is an ortho-
para director, so we expect nitration to occur at the ortho 
and para positions. Because of the size of the bromine 
atom, the para product is expected to predominate (a 
steric effect). 
 
 
(b) The reagents indicate a nitration reaction, so we must 
decide where the nitro group will be installed. The 
aromatic ring has one substituent (an isopropyl group) 
which is an ortho-para director, so we expect nitration to 
occur at the ortho and para positions. Because of the 
size of the isopropyl group, the para product is expected 
to predominate (a steric effect). 
 
 
(c) The reagents indicate a nitration reaction, so we must 
decide where the nitro group will be installed. The 
aromatic ring has one substituent (a nitro group) which is 
a meta director, so we expect nitration to occur at the 
meta position. 
 
 
(d) The reagents indicate a nitration reaction, so we must 
decide where the nitro group will be installed. The 
aromatic ring has one substituent (a carbonyl group) 
which is a meta director, so we expect nitration to occur 
at the meta position. 
 
 
(e) The reagents indicate a nitration reaction, so we must 
decide where the nitro group will be installed. The 
aromatic ring has one substituent (a methoxy group) 
which is an ortho-para director, so we expect nitration to 
occur at the ortho and para positions. The para product 
is likely to predominate (because of a steric effect). 
 
OMe
O2N
OMe
NO2
+
Major Minor 
18.42. 
(a) These reaction conditions indicate a sulfonation 
reaction, so we must decide where the sulfonic acid 
group will be installed. The aromatic ring has one 
substituent (Cl) which is an ortho-para director, so we 
expect sulfonation to occur at the ortho and para 
positions. For steric considerations, the para product 
(shown here) is likely to predominate over the ortho 
product. 
 
 
(b) These reaction conditions indicate a sulfonation 
reaction, so we must decide where the sulfonic acid 
group will be installed. The aromatic ring has one 
substituent (OH) which is an ortho-para director, so we 
expect sulfonation to occur at the ortho and para 
positions. For steric considerations, perhaps the para 
product (shown here) predominates over the ortho 
product, although it is a close call in this case. The OH 
group is similar in steric bulk to a methyl group, and we 
know that a methyl group provides little steric bulk (for 
example, sulfonation of toluene is expected to produce a 
mixture of ortho and para products, and the major 
product is difficult to predict). 
 
 
 
(c) These reaction conditions indicate a sulfonation 
reaction, so we must decide where the sulfonic acid 
group will be installed. The aromatic ring has one 
substituent (a carbonyl group) which is a meta director, 
so we expect sulfonation to occur at the meta position. 
 
 
 
(d) These reaction conditions indicate a sulfonation 
reaction, so we must decide where the sulfonic acid 
group will be installed. The aromatic ring has two 
substituents (OH and NO2). The directing effects are 
controlled by the more highly activating group, which is 
the OH group. As an activator, this group is an ortho-
para director, so we expect sulfonation to occur at the 
ortho and para positions. For steric considerations, the 
para product (shown here) is likely to predominate over 
the ortho product. 
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