A.
2-Hydroxymethylenecyclohexanone, Method 1. A mixture of
23 g. (1 g. atom) of sodium metal cut in approximately 1-cm. cubes,
2 l. of dry ether,
98 g. (103 ml., 1 mole) of redistilled cyclohexanone, and
110 g. (120 ml., 1.5 moles) of ethyl formate is placed in a
5-l. three-necked flask equipped with a
stirrer,
stopper, and
vent tube. The reaction is initiated by the addition of
5 ml. of ethyl alcohol to the stirred mixture, which is then placed in a cold
water bath. Stirring is continued for 6 hours. After standing overnight,
25 ml. of ethyl alcohol is added, and the mixture is stirred for an additional hour. After the addition of 200 ml. of water, the mixture is shaken in a
3-l. separatory funnel. The
ether layer is washed with 50 ml. of water, and the combined aqueous extracts are washed with
100 ml. of ether. The aqueous layer is acidified with
165 ml. of 6N hydrochloric acid, and the mixture is extracted twice with
300 ml. of ether. The
ether solution is washed with
25 ml. of saturated sodium chloride solution and then is dried by the addition of approximately
30 g. of anhydrous magnesium sulfate powder. The drying agent is removed by suction filtration, and the
ether is evaporated on the
steam bath. The residue is distilled under reduced pressure using a
6-inch Vigreux column. After a small fore-run there is obtained
88–94 g. (
70–74%) of
2-hydroxymethylenecyclohexanone, b.p.
70–72°/5 mm.,
nD25 1.5110 (Note
1).
2-Hydroxymethylenecyclohexanone, Method 2. A mixture of
50 g. (1 mole) of 48% sodium hydride dispersed in mineral oil (Note
2),
2 l. of dry ether, and
5 ml. of ethyl alcohol is placed in a
5-l. three-necked flask equipped with a stirrer,
dropping funnel, and vent tube. The reaction vessel is cooled by means of a cold water bath, and a solution of
98 g. (103 ml., 1 mole) of redistilled cyclohexanone and
110 g. (120 ml., 1.5 moles) of ethyl formate is added dropwise during 1 hour. Stirring is continued for 6 hours (Note
3), and the solution is allowed to stand overnight. After the addition of
20 ml. of ethyl alcohol, the mixture is stirred for 1 hour. Water (200 ml.) is added to the flask with stirring, the mixture is shaken in a
3-l. separatory funnel and the organic layer separated. The product is isolated according to the procedure described in Method 1. The yield of
2-hydroxymethylenecyclohexanone is the same by both methods.