Organic Syntheses, CV 3, 416
Submitted by J. H. Saunders
1
Checked by R. S. Schreiber and E. L. Jenner..
1. Procedure
A rapid stream of dry
acetylene is passed into approximately
1 l. of liquid ammonia in a
2-l. three-necked flask equipped with a gas inlet tube and a mechanical stirrer while
23 g. (1 gram atom) of sodium is added over a period of 30 minutes (Note
1) and (Note
2). The flow of
acetylene is then reduced (Note
3), and
98 g. (1 mole) of cyclohexanone is added dropwise. When this addition, which requires about an hour, is completed, the reaction mixture is allowed to stand for about 20 hours to permit the evaporation of nearly all the
ammonia (Note
4).
The solid residue is decomposed by adding approximately 400 ml. of ice and water, and the resulting mixture is carefully acidified with
50% sulfuric acid (Note
5). The organic layer is dissolved in 100 ml. of
ether and washed with
50 ml. of brine. The original aqueous phase and the
brine wash are then extracted with two
50-ml. portions of ether. The combined ethereal solutions are dried over anhydrous
magnesium sulfate and filtered, and the
ether is distilled. The product is then distilled under reduced pressure through a
good column (Note
6). The yield of
1-ethynylcyclohexanol is
81–93 g. (
65–75%), b.p.
74°/14 mm.;
n20D 1.4822 (Note
7).
2. Notes
1. The preparation of
sodium acetylide is based on the procedure of Vaughn, Hennion, Vogt, and Nieuwland.
2
2. The blue color of dissolved
sodium is discharged so rapidly by the
acetylene that it seldom spreads through the entire mixture.
3. The flow of
acetylene may be terminated before the
cyclohexanone is added. This operation, however, is alleged to increase the formation of glycol.
3
4. If all the
ammonia is allowed to evaporate and the residual solid is exposed to the air the yields may be decreased.
5. Upwards of 70 ml. is required. The amount depends upon the quantity of
ammonia remaining.
6. The submitters and the checkers used a
15-cm. Vigreux column.
7. The product may solidify to a colorless solid, m.p.
30°.
3. Discussion
This preparation is referenced from:
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