Oxidation of carbohydrates with the ferrate(VI) ion

Oxidation of carbohydrates with the ferrate(VI) ion

lo. 4144 Methyl a-B-galactopyranoside carbonate solution at 50°. the activity (purity) 4 (1.0 g) was dissolved in 50 ml of O.lM sodium Potassi...

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lo.

4144

Methyl a-B-galactopyranoside carbonate solution at 50°.

the activity

(purity)

4

(1.0 g) was dissolved in 50 ml of O.lM sodium

Potassium

solution in small portions.

ferrate

(3-5.0 g) was added to this

The amount of.potassium

of the preparation.

determined by paper chromatography

exchange resin and evaporated The product was separated methanol or ethanol.

in 6:4:3 v/v 1-butanol-pyridine-water

by treatment with Amberlite

1,5-pyranoside,

from remaining

(s40°).

ferric hydroxide by extraction with at 209 nm, indicating

the

with some unreacted

in aqueous solution at room temperature. presumably

starting

was oxidized with sodium hypoiodite6

IR-120(H+)

cation-exchange

to 7.5-8.0 with barium hydroxide

or sodium chlorite

redissolved

resin.

solution, concentrated

in hot water, and the precipitation

(2 0.3, water);

to about 100 ml and a-p-

It was then

and washing were repeated.

lit.8

[a], +99"

It

(c 1.03, water), stable as high as Finally,

the precipitate

and the solution was treated with Amberlite

exchange resin or sulfuric acid to remove barium ions. gave a colorless syrup which crystallized methyl a-g-galactopyranosiduronic +128O

barium methyl

up to 220-225' but turned light brown about ZOO';

215', turning light brown at about 200'. in hot water,

to

The pH of the eluate was adjusted

which was washed well with 75% ethanol.

did not melt at temperatures

7

and then passed through a column of

filtered; 2-3 volumes of ethanol were added to precipitate galactopyranosiduronate

5

containing mainly methyl a-g-galacto-hexodialdo-

sodium methyl a-_P-galactopyranosiduronate

lit.

cation-

under diminished pressure at low temperature

It had a strong absorbance

The preparation,

[al:' +93O

IR-120(H+)

The oxidation product could be reduced to the starting material with

sodium borohydride

Amberlite

and

the solution was centrifuged;

presence of sn aldehyde group, but was contaminated compound.

ferrate used depended upon

After reaction was complete as

spraying with silver nitrate and sodium hydroxide, and the filtrate was neutralized

40

acid,

was dissolved

IR-12O(H+)

cation-

Removal of the solvent

after cooling; yield 0.4 g (40%) of 3o +1400 [a),

(c 2.0, water), mp 107-108".

(2 2.0, water), mp 105-106';

4145

No. 40

waa oxidized

Methyl a-&nannopyranoside

[a]:' +50°

acid using the above procedure; [a], +57O

tive thin-layer

chromatography

glucopyranosiduronic calcium salt

[a]:

+75'

separated by prepara-

(2 0.16, water).

+24='), followed by conversion

([a]E5 +39O), evaporation,

[a]B 25 +16-+26'.

to be methyl a-pPreparation

of the

to the free acid with Amberlite

drying and redissolution,

gave products

The faster moving component was assumed to be a lactone(s).

Barker -et al. lo prepared

the sodium salt of methyl Neither

Easty'l made the barium salt.

Time‘11 --* et al l6 reported

a-l&glucopyranosiduronic

reported any physical

[a], +129'

In most ferrate oxidations,

the main product,

after long reaction times, nor oxidized

was not an acid, and from which no 2,4-dinitrophenyl-

could be formed.

haps, 3,6_hemiacetals

of

(5 1.0, water).

was a compound that could not be reduced with sodium borohydride with sodium hypoiodite,

constants.

the acid to be a syrup that was probably a mixture

the free acid and lactones;

hydrazone

lit."

on Silica Gel H with 7:2:1 v/v ethyl acetate-

acid, had

([ali

two components

The slower moving compound, believed

acetic acid-methanol.

acid.

(2 0.14, water), mp 120-123°;

was also oxidized using the same procedure.

The resulting pale yellow syrup contained

with

a-pmannopyranosiduronic

(c 1.4, water), mp 114-115O.

Methyl a-E-glucopyranoside

IR-12O(H+)

to methyl

These coumpounds

had lower Rf values and are, per-

or, more likely, a dimer or higher polymerization

product.

That they arise from ketones has not been ruled out. References 3, 279 (1971).

1.

R. J. Audette,

J. W. Quail, and P. J. Smith, Tetra. Letters,

2.

J. N. BeMiller

and S. D. Darling, U.S. Patent

3.

R. Ii. Wood, J. Amer. Chem. Sot., 80, 2038

4.

J. M. Schreyer and L. T. Ockennan, Anal. Chem., 23, 1312 (1951).

5.

M. L. Wolfrom

6.

R. Schaffer

7.

T. P. Nevell, Methods

8.

S. Morel1 and K. P. Link, J. Biol. Chem., 100, 385 (1933).

and A. Thompson, Methods

and H. S. Isbell, Methods Carbohyd.

3,632,802

(1972).

(1958).

Carbohyd. Carbohyd.

Chem., 2, 67 (1963). Chem., 2, 11 (1963).

Chem., 3, 182 (1963).

4146

9.

10.

No. 40

C. A. Marsh, J. Chem. Sot., 1578 (1952). T. E. Timell, W. Enterman,

F. Spencer, end E. J. Soltes, Can. J. Chem., 43,

2296 (1965). 11.

S. A. Barker, E. J. Bourne, and M. Stacey, Chem. Ind.

12.

D. B. Easty, J. Org. Chem., 27, 2102

(1962).

(London), 970

(1951).