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Chapter 17 581
Copyright © 2017 Pearson Education, Inc.
c.
CH
3
CH
2
O OCH
2
CH
3
C
O
CH
3
CH
2
O
−
+
O O
OCH
2
CH
3
add slowly
O
1.
2. HCl
d.
H OCH
2
CH
3
C
O
CH
3
CH
2
O
−
+
O O
H
add slowly
O
1.
2. HCl
e.
O
O
O
O
O
O
O
O
OH
H
2
SO
4
a Robinson
annulation
+
CH CH
3
CHCCH
3
O
Pd/C H
2
HO
−
70.
The positive iodoform test indicates that compound
B
is a methyl ketone. The two singlets with a ratio of
3:1 indicate that if the methyl group represents the “3”, there is only one other hydrogen in the compound
or if the methyl group represent the “1”, there are nine other hydrogens. The former does not agree with the
molecular formula. Therefore, the compound must have three identical methyl groups that are attached to a
carbon that is not attached to a hydrogen.
3,3-Dimethyl-1-butyne will show two singlets with a ratio of 9:1. When water is added, a methyl ketone
with two singlets with a ratio of 3:1 is formed.
CH
3
C C CH
CH
3
CH
3
two singlets (9:1)
H
2
SO
4
HgSO
4
H
2
O
CH
3
CH
3
C C
CH
3
CH
3
O
two singlets (3:1)