Organic Syntheses, CV 4, 13
Submitted by Gardner W. Stacy and Richard A. Mikulec
1.
Checked by John C. Sheehan, George A. Mortimer, and Norman A. Nelson.
1. Procedure
In a
1-l. three-necked round-bottomed flask, equipped with a sealed stirrer, a reflux condenser, a thermometer, and a dropping funnel, is dissolved
5 g. of mercuric oxide (Note
1) in a solution of
8 ml. of concentrated sulfuric acid and 190 ml. of water. The solution is warmed to 60°, and
49.7 g. (0.40 mole) of 1-ethynylcyclohexanol (Note
2) is added dropwise over a period of 1.5 hours. After the addition has been completed, the reaction mixture is stirred at 60° for an additional 10 minutes and allowed to cool. The green organic layer which settles is taken up in
150 ml. of ether, and the aqueous layer is extracted with four
50-ml. portions of ether (Note
3). The combined ethereal extracts are washed with
100 ml. of saturated sodium chloride solution (Note
4) and dried over
anhydrous sodium sulfate. The drying agent is removed, the
ether is evaporated, and the residue is distilled under reduced pressure through a
15-cm. column packed with glass helices. The
1-acetylcyclohexanol is collected at
92–94°/15 mm. as a colorless liquid,
n25D 1.4670,
d254 1.0248 (Note
5). The yield is
37–38 g. (
65–67%).
2. Notes
1.
Mallinckrodt mercuric oxide red (analytical reagent or N.F. 1x grade) was used.
3. To facilitate subsequent extractions, the solid material remaining after separation of as much of the aqueous phase as possible should be removed by gentle suction filtration and washed with
25 ml. of ether.
4. The
sodium chloride solution removes the green color from the
ether extract, leaving a yellow solution.
5. The checkers found b.p.
100°/21 mm.,
nD25 1.4662–1.4665,
d425 1.0235–1.0238. Others have reported b.p.
92–94°/12 mm.,
d020 1.0256;
3 b.p.
91°/11 mm.,
nD11 1.4726,
d411 1.1033;
4 b.p.
88.0–88.6°/12 mm.,
nD28 1.4712.
5
Establishing a criterion for the purity of the product is of particular importance because of the known tendency of ethynylcarbinols to undergo rearrangement.
5,6 The authors have reported that consecutive small fractions of the distillate possess a constant boiling point and refractive index. Furthermore, representative fractions, treated with
periodic acid and subsequently with
2,4-dinitrophenylhydrazine, give
cyclohexanone 2,4-dinitrophenylhydrazone in
83% over-all yield in a high state of purity.
3. Discussion
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