A.
Reduction and hydrolysis. A solution of
129 g. (0.75 mole) of β-naphthyl ethyl ether in
1.5 l. of 95% ethanol is prepared in a
5-l. three-necked flask fitted with a
mechanical stirrer, a
bulb condenser topped by a
Friedrichs condenser, and a Y-tube to allow for the introduction of
nitrogen and
sodium. The apparatus is flushed thoroughly with
nitrogen, the
nitrogen flow is reduced, and
225 g. (9.8 g. atoms) of sodium is added in small portions (Note
1), with efficient stirring, at a rate sufficient to maintain vigorous boiling. The
hydrogen liberated passes through the condensers and a
delivery tube into a
hood or directly out a window. When approximately two-thirds of the
sodium has been introduced, an additional
375 ml. of 95% ethanol is added to reduce the viscosity of the reaction mixture. Approximately 1.5 hours is required for the addition of the
sodium. Near the end of this period, the rate of the reaction decreases and heat is supplied by means of an
electric heating mantle to maintain the reflux temperature (Note
2).
After all the
sodium has dissolved, the
hydrogen is thoroughly swept from the system with
nitrogen and the heating is discontinued. The Y-tube is replaced by a
separatory funnel, and 750 ml. of water is added cautiously (Note
3), with stirring, followed by
1.5 l. of concentrated hydrochloric acid (Note
3). The acidic mixture containing precipitated
sodium chloride is heated, with stirring, at the reflux temperature for 30 minutes, and then allowed to cool.
The mixture is extracted with ten
175-ml. portions of benzene or 1:1
benzene-ether mixture (Note
4). The combined extract is washed with 75-ml. portions of water until the washings are neutral to litmus. The organic solvent is removed by distillation on a
steam bath. The crude oily residue is converted directly (Note
5) to the
β-tetralone bisulfite addition product.