Org. Synth. 1955, 35, 49
DOI: 10.15227/orgsyn.035.0049
DIACETYL-d-TARTARIC ANHYDRIDE
[Tartaric anhydride, diacetate of d-]
Submitted by R. L. Shriner and C. L. Furrow, Jr.
1.
Checked by N. J. Leonard and R. R. Sauers.
1. Procedure
In a 500-ml. three-necked round-bottomed flask fitted with a liquid-sealed stirrer and two reflux condensers (Note 1) is placed 40 g. (0.27 mole) of anhydrous, powdered d-tartaric acid (Note 2). A solution of 1.2 ml. of concentrated sulfuric acid in 136 g. (126 ml., 1.33 moles) of acetic anhydride is added, and the stirrer is started. The mixture warms up, and the tartaric acid goes into solution. The solution is heated gently (Note 1) under reflux with stirring for 10 minutes. The solution is poured into a beaker and cooled for 1 hour in an ice bath. The crude crystalline product is collected on a 15-cm. Büchner funnel (Note 3), washed twice with 20-ml. portions of dry benzene, stirred mechanically with 175 ml. of cold absolute ether, filtered, and placed in a vacuum desiccator over phosphorus pentoxide and paraffin shavings for 24 hours. The yield of diacetyl-d-tartaric anhydride is 41–44.5 g. (71–77%), m.p. 133–134° (Note 4), [α]D20 97.2° in dry chloroform (c = 0.47).
2. Notes
1.
The reaction may be quite vigorous at its start, and the use of a large flask with two condensers is advised.
2.
The anhydrous
d-tartaric acid was obtained from Matheson, Coleman and Bell, East Rutherford, New Jersey.
3.
Additional but lower-grade product may be acquired by pouring the mother liquor into
petroleum ether and filtering the mixture. The recovered product is washed twice with absolute
ether, filtered, and dried. About
7 g. of product, m.p.
129–131°, is thus obtained.
4.
The product is not stable and should be prepared only as needed. It may be kept in a vacuum desiccator over
phosphorus pentoxide and paraffin, but the melting point drops about 1 degree during the first 4 days and then remains constant at approximately 132–134°. If placed in an ordinary
stoppered bottle, the product becomes gummy and the melting point falls to about 100° within 3 days. Attempts to recrystallize the anhydride invariably led to decomposition and lowered melting point.
3. Discussion
The acetylation of
d-tartaric acid with
acetic anhydride has been effected by means of
sulfuric acid,
2,3 hydrogen chloride,
4 or
85% phosphoric acid.
5
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
petroleum ether
Tartaric anhydride, diacetate of d-
sulfuric acid (7664-93-9)
hydrogen chloride (7647-01-0)
Benzene (71-43-2)
ether (60-29-7)
acetic anhydride (108-24-7)
chloroform (67-66-3)
phosphoric acid (7664-38-2)
tartaric acid (87-69-4)
phosphorus pentoxide (1314-56-3)
D-tartaric acid (147-71-7)
Diacetyl-D-tartaric anhydride
Copyright © 1921-, Organic Syntheses, Inc. All Rights Reserved