Organic Syntheses, CV 2, 262
Submitted by Homer Adkins, Neville Isbell, and Bruno Wojcik.
Checked by John R. Johnson and H. R. Snyder.
1. Procedure
In a
3-l. three-necked, round-bottomed flask, fitted with a
mechanical stirrer,
reflux condenser, and
separatory funnel, is placed
400 cc. of absolute alcohol (Note
1). Through the condenser tube is added slowly
23 g. (1 gram atom) of clean sodium cut into thin slices. The completion of the reaction is hastened by heating the flask on a
steam bath. When the
sodium has dissolved completely,
143 g. (1.1 moles) of ethyl acetoacetate (Org. Syn. Coll. Vol. I, 1941, 235) is introduced slowly. After the mechanical stirrer is started,
123 g. (1 mole) of ethyl chloroacetate (Note
2) is added slowly over a period of an hour, and the reaction mixture is refluxed for five to six hours. At this point the reaction mixture should no longer give an alkaline reaction with moist litmus.
After cooling, the precipitated
sodium chloride is removed by filtering with suction and is washed with two
50-cc. portions of absolute alcohol. The alcohol is removed by distilling through a
short column from a steam bath. The residue is filtered and transferred to a round-bottomed flask and is fractionated under reduced pressure through a
Widmer column containing an 8-cm. spiral (Note
3). The fraction boiling at
121–124°/5 mm. is collected. The yield is
121–134 g. (
56–62 per cent of the theoretical amount) (Note
4).
2. Notes
2.
Ethyl chloroacetate boiling at
142–145° was used. This ester can be prepared readily by refluxing for six hours a mixture of
200 g. of chloroacetic acid,
120 g. ofabsolute alcohol, and
25 g. of concentrated sulfuric acid.
1 The product is purified in the conventional way, and the yield is
185 g. (
70 per cent of the theoretical amount).
3. It is advantageous to use an
electrically heated column for this fractionation. The principal by-product of the reaction is
ethyl β-acetotricarballylate2 (b.p. 190°/16 mm.), formed by further action of
ethyl chloroacetate upon the initial product.
3. Discussion
This preparation is referenced from:
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