Org. Synth. 1939, 19, 4
DOI: 10.15227/orgsyn.019.0004
ACETYLGLYCINE
[Aceturic acid]
Submitted by R. M. Herbst and D. Shemin.
Checked by Reynold C. Fuson and E. A. Cleveland.
1. Procedure
In a
1-l. Erlenmeyer flask provided with a
mechanical stirrer are placed
75 g. (1 mole) of glycine (Org. Syn. Coll. Vol. I, 1941, 298) and 300 cc. of water. The mixture is stirred vigorously until the
glycine is almost completely dissolved, when
215 g. (2 moles) of 95 per cent acetic anhydride (Note 1) is added in one portion. Vigorous stirring is continued for fifteen to twenty minutes, during which time the solution becomes hot and
acetylglycine may begin to crystallize. The solution is placed in the
refrigerator (Note 2) overnight to effect complete crystallization. The precipitate is collected on a
Büchner funnel, washed with ice-cold water, and dried at 100–110°. This product weighs
75–85 g. and melts at
207–208°. The combined filtrate and washings are evaporated to dryness under reduced pressure on a
water bath at 50–60°. The residue on recrystallization from 75 cc. of boiling water yields a second fraction, of
20–30 g., which melts at
207–208° after being washed with ice-cold water and dried at 100–110°. An additional
4–6 g. of only slightly less pure product may be obtained from the mother liquor by concentration. The total yield is
104–108 g. (
89–92 per cent of the theoretical amount)
(Note 3).
2. Notes
1.
The equivalent quantity of
90 per cent acetic anhydride may be used.
2.
The refrigerator used by the checkers maintained a temperature of 5–7°.
3.
The method may be employed to acetylate most α-amino acids with only slight modifications depending upon the solubility of the particular amino acid. When optically active amino acids are acetylated, there is little or no racemization.
1
3. Discussion
Acetylglycine has been prepared by the interaction of
acetyl chloride and the
silver salt of glycine in dry
ether or
benzene;
2,
3 by the action of
acetic anhydride on
glycine suspended in warm
benzene;
3 by heating
glycine with
acetic anhydride;
4 by treating an aqueous solution of
glycine or its sodium salt with
ketene;
5 and by treating an aqueous alkaline solution of
glycine with
acetic anhydride.
6
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
glycine or its sodium salt
Benzene (71-43-2)
ether (60-29-7)
acetic anhydride (108-24-7)
acetyl chloride (75-36-5)
Glycine (513-29-1)
Ketene (463-51-4)
Acetylglycine,
Aceturic acid (543-24-8)
silver salt of glycine
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