While a current of dry
nitrogen is passed through the apparatus,
400 ml. of dry ether and
6.9 g. (1 gram atom) of lithium (in small pieces) (Note
1) are placed in a
1-l. three-necked flask fitted with a dropping funnel, mechanical stirrer, and reflux condenser protected from moisture. The stirrer is started, and
10–15 ml. of a solution of 79 g. (0.5 mole) of dry bromobenzene in
100 ml. of dry ether is added from the dropping funnel. The reaction usually starts immediately; if not, the flask may be warmed, and the remainder of the mixture is then added at such a rate that the
ether refluxes gently. The mixture is stirred until the
lithium disappears (Note
2).
Forty-six grams (0.5 mole) of α-picoline (Note
3) is then added, and the mixture is stirred at room temperature for 1 hour, during which time the dark red solution of
picolyllithium is formed. The flask is then immersed in an
ice-salt bath, and when the mixture is thoroughly chilled the
nitrogen train is disconnected. Then
20 g. of dry acetaldehyde in
50 ml. of dry ether (Note
4) is slowly dropped into the mixture over a period of 20 minutes. The red color entirely disappears. After 15 minutes, 100 ml. of water is slowly added and then
100 ml. of concentrated hydrochloric acid (sp. gr. 1.2). The aqueous layer is removed and poured, with stirring, into a warm solution of
300 g. of sodium carbonate decahydrate in 100 ml. of water (Note
5). The crude reaction product separates as an oil and is taken up in
300 ml. of chloroform. The precipitated
lithium carbonate is filtered, transferred to a
beaker, and stirred with four
200-ml. portions of chloroform. The
chloroform extracts are decanted or filtered, and all the
chloroform solutions are combined (Note
6). The
chloroform is removed by distillation, and the residue is fractionated under reduced pressure through a
good column. The
1-(α-pyridyl)-2-propanol boils sharply at
116–117°/17 mm. (
124–125°/20 mm.). A small fore-run and a considerable amount of high-boiling residue are discarded. The yield is
30–34 g. (
44–50% based on the
α-picoline) (Note
7) and (Note
8). This product darkens on exposure to light, and it should be preserved in a brown glass bottle.