Org. Synth. 1945, 25, 53
DOI: 10.15227/orgsyn.025.0053
β-d-GLUCOSE-2,3,4,6-TETRAACETATE
[D-Glucose, β-2,3,4,6-tetraacetyl-]
Submitted by Chester M. McCloskey and George H. Coleman.
Checked by C. S. Hamilton, Robert Angier, and Ivan Baumgart.
1. Procedure
A solution of
82.2 g. (0.2 mole) of acetobromoglucose (p. 11) (Note 1) in
125 ml. of dry acetone (Note 2) in a
250-ml. flask is cooled to 0° in an
ice bath. To the cold solution is added 2.3 ml. of water and then
46.5 g. (0.17 mole) of silver carbonate (Note 3) in small portions in the course of 15 minutes. The mixture is shaken well during the addition and for 30 minutes longer
(Note 4). The mixture is then warmed to 50–60° and filtered. The mass of silver salts is washed with
65 ml. of dry acetone (Note 5), removed from the funnel, warmed in a flask with
65 ml. more of acetone, filtered, and washed again on the funnel.
The combined filtrates are concentrated under reduced pressure in a 500-ml. filter flask (Note 6) until most of the solution is filled with crystals. The mixture is warmed to dissolve the crystals, the solution is poured into a 600-ml. beaker, and an equal volume of absolute ether and a similar volume of ligroin are added. The resulting solution is cooled in a freezing mixture with gentle stirring. The crystals of the tetraacetate form quickly and after about 10 minutes are filtered and air-dried. The crystals so obtained melt at 132–134° (Note 7). If a purer product is required, the product is dissolved in acetone, and ether and ligroin are added to the solution in the manner described. The yield of once-crystallized product melting at 132–134° is 52–56 g. (75–80%).
2. Notes
1.
The
acetobromoglucose that was used had a melting point of
87–88°.
2.
The
acetone was dried over
calcium chloride.
3.
The
silver carbonate should be freshly prepared and finely ground.
Silver carbonate can be prepared by the addition of a solution of
sodium carbonate (53 g. in 600 ml. of water) to one of
silver nitrate (172 g. in 2 l. of water). This is a very slight excess of the
silver nitrate. The
sodium carbonate solution is added slowly (10 minutes), and the reaction mixture is stirred vigorously with a
mechanical stirrer. The
silver carbonate is filtered, washed with a little
acetone to facilitate drying, and then air-dried. All operations are carried out in dim light.
4.
At the end of this time, evolution of
carbon dioxide should no longer be appreciable. The time required for the reaction depends largely on the agitation of the
silver carbonate. In large runs mechanical stirring is required.
5.
Anhydrous chemicals are used throughout as the presence of any appreciable amount of water interferes with the crystallization of the tetraacetate.
6.
The solution is not heated during the concentration, and thus the temperature is maintained below that of the room by the evaporation of the solvent. If a capillary is used it should be equipped with a
drying tube.
7.
β-d-Glucose-2,3,4,6-tetraacetate (2,3,4,6-tetraacetyl-β-d-glucose) decomposes slightly on prolonged standing and after 1–2 months has a melting range of 5–8 degrees. Such material can be purified by recrystallization.
3. Discussion
β-d-Glucose-2,3,4,6-tetraacetate has been prepared usually by the hydrolysis of
acetobromoglucose.
1
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
ligroin
calcium chloride (10043-52-4)
ether (60-29-7)
silver nitrate (7761-88-8)
sodium carbonate (497-19-8)
carbon dioxide (124-38-9)
acetone (67-64-1)
d-Glucose (492-62-6)
Acetobromoglucose (572-09-8)
β-D-Glucose-2,3,4,6-tetraacetate
silver carbonate (534-16-7)
2,3,4,6-tetraacetyl-β-d-glucose
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