In a
1-l. three-necked flask, fitted with a
dropping funnel, a
thermometer,
mechanical stirrer, and
reflux condenser protected from moisture (Note
1), the whole being swept with dry
nitrogen, are placed
3.5 g. (0.5 gram atom) of lithium, cut into pieces the size of a pea, and
100 cc. of dry ether. The stirrer is started, and about
10 cc. of a mixture of 40 g. of bromobenzene (0.25 mole) in 50 cc. of dry ether is admitted from the dropping funnel; a vigorous reaction usually takes place (Note
2). The remainder of the mixture is added gradually over a half-hour period, when the metal should have largely disappeared (Note
3).
From the dropping funnel is next slowly introduced, with stirring,
40 g. (0.5 mole) of dry pyridine (Note
4) in
100 cc. of dry toluene. The
ether is then distilled (Note
5) and the residual suspension stirred at 110° (inside temperature) for eight hours. It is then cooled to about 40°, 35 cc. of water cautiously added, and the liquids filtered if necessary (Note
6). The lower layer is separated and discarded. The
toluene layer is dried for an hour with
20 g. of pulverized potassium hydroxide and carefully distilled, using a
modified Claisen flask with a fractionating column attached. The material boiling up to 150° is removed at ordinary pressure and the residue distilled
in vacuo; after two fractional distillations, the yield of
2-phenylpyridine, b.p.
140°/12 mm., is
15.5–19 g. (
40–49 per cent of the theoretical amount).