Adapted from PLTL
Chem 227/ Dr. Rusay
Turn in answers to the questions only on the form provided.
Carbohydrates
1. Reminder: A Fischer projection is a way of representing 3-D molecules on 2-D surfaces. As in all
conventions, there are specific rules to be obeyed. (R)-Glyceraldehyde is the simplest monosaccharide.
Convert the 3-D representation into a Fischer projection formula.
H
HO
CH 2OH
HC O
(R)-(+)-glyceraldehyde
2. Refer to: http://ep.llnl.gov/msds/orgchem/Chem227/naming.html
a. Draw a Fischer projection formula or Haworth formula for each of the six compounds.
b. Name each carbohydrate: detailed generic or precise names accepted. Clearly identify any that are
not "carbohydrates".
c. For each of the models that are carbohydrates, indicate if it is a mono-, di-, or polysaccharide and if
it is a reducing or a non-reducing sugar.
3. Provide structures that satisfy the following descriptions:
a. The aldopentose that would give the same aldaric acid as D-arabinose upon oxidation with nitric
acid.
b. The aldohexose that gives an optically inactive aldaric acid upon treatment with nitric acid and
gives D-ribose on sequential treatment with (i) Br2, H2O, and (ii) Fe2(SO4)3, H2O2.
c. The enediol that is an intermediate in the isomerization of the carbonyl group of D-arabinose from
the 1-position to the 2-position in aqueous base.
4. Provide structures for the major organic products of the following reactions:
CH3O
a.
OCH3
H3O , H2 O
O
CH3O
OCH3
b.
D-mannose
c.
D-glucose
OCH3
CH3 CH2OH
(give Fischer projection)
(give chair conformation of product(s))
cat H3 O
NaBH 4
H2O
(draw Fischer projection)
Adapted from PLTL
O
2 H 3C
d.
CH3
D-glucose
cat H3 O
a primary alcohol, C12H 20O6
(give chair conformation)
CHO
H
e.
HO
H
OH
H
OH
CH2 OH
1. HCN, CN
2. H3O , H2O, !
3. H2, Pd(BaSO4)
4. H3O , H2O
Adapted from PLTL
5.
Optically active carbohydrate A (C14H20O7) does not react with Cu(II) complex (indicates an
aldehyde is not present), and upon treatment with dilute HCl gives optically active carbohydrate B
(C7H14O7) plus benzyl alcohol. Reaction of A with excess dimethyl sulfate gives C, which upon
dilute acid hydrolysis gives the optically active 2,3,5,6,7-pentamethyl aldoheptose D. When B is
treated with nitric acid, optically inactive E is formed. Oxidative removal of C1 of B gives D-glucose.
Give structures A through E consistent with this information.
Cu+2 (complex)
no reaction
H2O, OH
dil. HCl
A C14H20O7
B (C7 H14O7) +
optically active
H2O
optically active
CH2 OH
O
CHO
CH3 OSOCH3
CHOMe
O
dil. HCl
C
–OH/H
2O
H2O
CHOMe
D =
optically
active
CHOH
CHOMe
CHOMe
CH2 OMe
B
HNO3
H2O
E
optically
inactive
CHO
H
1. Br2/H2O
2. Fe 2(SO4)3/H2 O2
HO
OH
H
H
OH
H
OH
CH2 OH
D–glucose
Adapted from PLTL
6. Complete the Wordsearch on the turn in form.
7. Refer to: http://ep.llnl.gov/msds/orgchem/Chem227/naming.html
II.a) Select two planets that reflect the proportional difference between the size of a glucose molecule relative to
a virus.
b) Select three planets that reflect the proportional difference between the respective sizes of a virus, a
bacterium and a red blood cell.
c) How many glucose molecules could be contained within: i) the space of a virus and ii) the space of a red
blood cell?
(V = 4.189 r3) Show your respective calculations.