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Chapter 20 689
Copyright © 2017 Pearson Education, Inc.
45.
O
HO
OH
CH
2
OH
HO
O
HO
HOCH
2
O
CH
2
OH
OH
46.
The hexose is d-altrose.
1.
Knowing that
1
+
2
-glyceraldehyde is d-glyceraldehyde gives the configuration at C-5.
2.
Knowing that the second Wohl degradation gives d-erythrose gives the configuration at C-4.
3.
Knowing that the first Wohl degradation followed by oxidation gives an optically inactive aldaric acid
gives the configuration at C-3.
4.
Knowing that the original hexose forms an optically active aldaric acid gives the configuration at C-2.
H
H OH
H OH
H OH
CH
2
OH
D
-altrose
HO
H OH
H OH
H OH
CH
2
OH
H OH
H OH
CH
2
OH
H OH
CH
2
OH
C
H O
C
H O
C
H O
C
H O
47.
O
HO
HO
HO
H
CH
2
OH
+
Cl
−
OH
O
HO
HO
HO
H
CH
2
OH
OH
H
+
+
O
HO
HO
HO
CH
2
OH
H
+
H
2
O
H Cl
+
H
3
O
+
H
O
HO
HO
HO
O H
CH
2
OH
H
+
H
2
O
O
HO
HO
HO
OH
CH
2
OH
H