The reaction is conducted in a
500-ml. round-bottomed three-necked flask to which are attached
(ground-glass joints) a rubber slip-sleeve-sealed wire stirrer, a
thermometer, and a
pressure-equalized dropping funnel. The top of the dropping funnel is connected to a system for exhausting and filling with
nitrogen (p. 133). The apparatus is flame-dried at reduced pressure, and the flask is charged with
14.50 g. (0.148 mole) of freshly distilled cyclohexanone and
18.15 g. (0.148 mole) of freshly distilled ethyl chloroacetate. A solution of
6.0 g. (0.153 g. atom) of potassium in 125 ml. of dry tert-butyl alcohol (Note
1) and (Note
2) is introduced into the dropping funnel, and the system is exhausted and filled with
nitrogen. The flask is cooled with an
ice bath, stirring is commenced, and the solution of
potassium tert-butoxide is added from the dropping funnel over a period of about 1.5 hours, the temperature of the reaction mixture being maintained at 10–15°. After the addition is complete, the mixture is stirred for an additional 1–1.5 hours at about 10°. Most of the
tert-butyl alcohol is removed by distillation from the reaction flask at reduced pressure (
water aspirator) and a bath temperature of 100°. The oily residue is taken up in
ether. The
ether solution is washed with water, then with saturated aqueous
sodium chloride solution, and is finally dried over anhydrous
sodium sulfate. The residue obtained on evaporation of the
ether is distilled through a
6-in. Vigreux column to give
22.5–26.0 g. (
83–95% yield) of colorless glycidic ester, b.p.
134–137°/21 mm.,
147–152°/30 mm.,
n25D 1.4568–1.4577 (Note
3).