A Publication of Reliable Methods for the Preparation of Organic
Compounds Annual Volume Org. Synth. 1969, 49, 62 DOI:
10.15227/orgsyn.049.0062 [Oxepin, 2,7-dimethyl-] Submitted by L.
A. Paquette and J. H. Barrett1. Checked by Jon Malmin and Ronald
Breslow. 1. Procedure   A. 1,2-Dimethyl-1,4-cyclohexadiene.
Caution! This step should be conducted in a hood to avoid
exposure to ammonia fumes. A 5-l. three-necked flask, cooled in
a dry ice-isopropyl alcohol bath, is fitted with an efficient
stirrer and a dry ice condenser. The flask is charged with
approximately 2.5 l. of liquid ammonia, the stirrer is started,
and 450 g. of anhydrous diethyl ether, 460 g. (10 moles) of
absolute ethanol, and 318.5 g. (3.0 moles) of o-xylene (Note 1)
are added slowly in that order (Note 2). Then 207 g. (9.0 g.
atoms) of sodium is added in small pieces over a 5-hour period
(Note 3). The ammonia is allowed to evaporate overnight. The
flask is now equipped with a reflux condenser, and approximately
800 ml. of ice water is slowly add