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

O

H

C

H

2

O

H

H

C

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:

O

CH3O OCH3

OCH3CH3O

OCH3

a.

b. D-mannose (give chair conformation of product(s))

(draw Fischer projection)

CH3CH2OH

cat H3O

NaBH4

H2Oc. D-glucose

H3O , H2O(give Fischer projection)

Adapted from PLTL

a primary alcohol, C12H20O6(give chair conformation)d. D-glucose

2 H3C CH3

O

cat H3O

e.

2. H3O , H2O, !

1. HCN, CN

3. H2, Pd(BaSO4)

CHO

H OH

HO H

H OH

CH2OH4. 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.

dil. HCl

H2O

Cu+2 (complex)no reaction

H2O, OH

CH2OH

O

CH3OSOCH3

–OH/H2OC

dil. HCl

H2OD

opticallyactive

BHNO3

H2OE

opticallyinactive

CHO

CHOMe

CHOMe

CHOH

CHOMe

CHOMe

CH2OMe

H

CHO

OH

HHO

OHH

OHH

CH2OH

D–glucose

O

B (C7H14O7) +A C14H20O7

=

1. Br2/H2O

2. Fe2(SO4)3/H2O2

optically active optically active

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.