Organic Syntheses, CV 5, 887
Submitted by Charles E. Braun and Clinton D. Cook
1.
Checked by W. G. Woods, E. F. Silversmith, and John D. Roberts.
1. Procedure
A.
2,3,4,6-Tetra-O-acetyl-D-gluconic acid monohydrate. Crushed, fused
zinc chloride (20 g.) is shaken with
250 ml. of acetic anhydride in a
1-l. three-necked flask until most of the solid dissolves. The flask is then equipped with
mechanical stirrer,
thermometer reaching into the liquid, and a
dropping funnel. As the flask is cooled in an
ice bath,
50 g. (0.28 mole) of D-glucono-δ-lactone (Note
1) is added slowly with vigorous stirring. During the addition, the temperature should be kept below 65°. After an hour in the ice bath, the solution is kept at room temperature for 24 hours and is then poured into 1 l. of water and stirred until the hydrolysis of the
acetic anhydride is complete (about an hour). The mixture is placed in a refrigerator until the product crystallizes completely (Note
2). The crude material is removed by filtration and washed with a small amount of ice water. The
2,3,4,6-tetra-O-acetyl-D-gluconic acid monohydrate thus obtained melts at
113–117°. The yield is
79–84 g. (
74–79%).
B.
2,3,4,5,6-Penta-O-acetyl-D-gluconic acid. Tetra-O-acetyl-D-gluconic acid monohydrate (50 g., 0.13 mole) is slowly added to a chilled (0–5°) solution of
18 g. of fused zinc chloride in 190 ml. of acetic anhydride contained in a
1-l. Erlenmeyer flask. The solution is kept in an ice bath for an hour and then allowed to stand at room temperature for 24 hours. After dilution with 1 l. of water, the solution is extracted with four
100-ml. portions of chloroform. In order to remove the
chloroform, 200 ml. is distilled,
250 ml of toluene is added, and 250 ml. of this solution is distilled. Another
250 ml. of toluene is then added and the volume is reduced to 300 ml. The product crystallizes on standing at 0° (Note
2). The solid is removed by filtration, washed with
toluene and then with
petroleum ether (b.p.
35–55°). A yield of
44–45 g. (
83–84%) of anhydrous
2,3,4,5,6-penta-O-acetyl-D-gluconic acid, melting at
110–111°, is obtained;
[α]D23 +11.5° (
c = 4.0 in ethanol-free
chloroform).
C.
2,3,4,5,6-Penta-O-acetyl-D-gluconyl chloride. Anhydrous
2,3,4,5,6-penta-O-acetyl-D-gluconic acid (25 g., 0.062 mole) is shaken with
185 ml. of anhydrous ethyl ether in a
1-l. round-bottomed flask until most of the solid dissolves. Then
15 g. (0.072 mole) of phosphorus pentachloride is added with shaking. The flask is fitted with a
calcium chloride drying tube and stored overnight at room temperature. Any solid material is removed by filtration through a
fritted-glass funnel into a 1-l. round-bottomed flask, and the ethereal solution is concentrated to about one-half volume under reduced pressure at room temperature. The concentrated solution is allowed to stand overnight at 0° or below. The mother liquor is decanted from the crystals, which are then broken up, transferred to a fritted-glass funnel, washed quickly with
petroleum ether (b.p.
35–55°), and dried in a
vacuum desiccator. The mother liquor is again concentrated to one-half its volume under reduced pressure and a second crop of crystals collected. The total yield of
2,3,4,5,6-penta-O-acetyl-D-gluconyl chloride, melting at
68–71° (Note
3), is
21–24 g. (
80–92%), depending on the temperature of crystallization (Note
4) and (Note
5).
2. Notes
1. The
D-glucono-δ-lactone (m.p.
153–155°; assay > 99%, Pfizer specification; water content < 0.2%, Karl Fischer titration) is obtained from Charles Pfizer & Co., Inc., 630 Flushing Avenue, Brooklyn 6, New York. Material having a water content greatly in excess of 0.2% may be dried for 48 hours at 100°. Drying at higher temperatures has in some samples produced decomposition. Independent experience with many preparations in the laboratories of one of the editors (Max Tishler, Merck Sharp & Dohme Research Laboratories) has indicated that drying is generally not necessary.
2. As long as 48 hours may be required.
3. The checkers found m.p.
69.5–74°.
5. The submitters report
[α]D23° = +2.2 (
c = 4.0 in ethanol-free
chloroform). The checkers found
[α]D25° = +2.5°.
3. Discussion
The method followed for the preparation of the two acids is a modification of that of Major and Cook.
2 The preparation for
penta-O-acetyl-D-gluconyl chloride is that of Braun and coworkers.
3 A slightly different technique has also been described.
4
Appendix
Compounds Referenced (Chemical Abstracts Registry Number)
petroleum ether
ethyl ether (60-29-7)
acetic anhydride (108-24-7)
phosphorus pentachloride (10026-13-8)
chloroform (67-66-3)
toluene (108-88-3)
zinc chloride (7646-85-7)
D-glucono-δ-lactone (90-80-2)
2,3,4,6-Tetra-O-acetyl-D-gluconic acid monohydrate
2,3,4,5,6-PENTA-O-ACETYL-D-GLUCONIC ACID (17430-71-6)
2,3,4,5,6-PENTA-O-ACETYL-D-GLUCONYL CHLORIDE,
penta-O-acetyl-D-gluconyl chloride (53555-69-4)
Gluconic acid, pentaacetyl-,D-
Tetra-O-acetyl-D-gluconic acid monohydrate
Gluconyl chloride, pentaacetyl-, D-
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