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Chapter 20 687
Copyright © 2017 Pearson Education, Inc.
40.
HOCH
2
HOCH
2
O
OCH
3
HO OH
O
OCH
3
HO OH
methyl -
D
-ribofuranose
methyl -
D
-ribofuranose
O
OCH
3
OH HO
HO
O OCH
3
OH HO
HO
methyl -
D
-ribopyranose
methyl -
D
-ribopyranose
41.
a.
methyl
b
-d-sorboside
b.
ethyl
b
-d-guloside
c.
methyl
a
-d-idoside
42.
A monosaccharide with a molecular weight of 150 must have five carbons (5 Cs
=
60, 5 Os
=
80, and
10 Hs
=
10 for a total of 150). All aldopentoses are optically active. Therefore, the compound must be a
ketopentose. The following is the only ketopentose that is not optically active.
CH
2
OH
OH H
C O
OH H
CH
2
OH