A
2-l. round-bottomed three-necked flask is fitted with a reflux condenser, a dropping funnel, and an efficient mechanical stirrer. A
calcium chloride tube is attached to the condenser to protect the apparatus from moisture. To the flask are added
800 ml. of absolute ether and
13.9 g. (2 gram atoms) of lithium chips or shavings (Note
1). The stirrer is started, and
105 ml. (157 g., 1 mole) of dry bromobenzene is placed in the dropping funnel. About
5–15 ml. of the bromobenzene is added to initiate the reaction; when the
ether begins to reflux, the balance is added at such a rate that the solvent refluxes continuously (1 hour) (Note
2). The mixture is then stirred and refluxed until most of the
lithium disappears (45–90 min.). While stirring is continued,
97 ml. (93.1 g., 1 mole) of α-picoline is added dropwise in about 5–10 minutes. The dark red-brown solution of
picolyllithium is stirred for an additional 30 minutes and is then poured slowly and with shaking onto 500–750 g. of crushed Dry Ice contained in a
3-l. round-bottomed flask (Note
3). The mixture is stirred well until the dark color of the
picolyllithium is discharged, and the excess of Dry Ice is allowed to evaporate. The
ether is removed by distillation under reduced pressure at room temperature. The lumpy residue of lithium salts is broken up, and to it is added
750 ml. of commercial absolute ethanol. The solution is saturated with dry
hydrogen chloride while cooling in an
ice bath. The esterification mixture is allowed to stand overnight, after which the solvent is removed as completely as possible by distillation under reduced pressure on a
steam bath. The syrupy residue is dissolved in
750 ml. of chloroform, and a paste prepared from
225 g. of potassium carbonate and 135 ml. of water is slowly added to the solution with mechanical stirring. After the paste has been added, the solution is stirred vigorously and is kept just below the boiling point for 1 hour. The
chloroform solution is decanted from the inorganic salts, and the
chloroform is removed by distillation. The residue is fractionated under reduced pressure from a
modified Claisen flask with a fractionating side arm. About
40 g. of α-picoline is recovered in the fore-run, and the
ethyl 2-pyridylacetate is obtained as a light yellow liquid, b.p.
135–137° /28 mm.,
142–144° /40 mm.,
109–112° /6 mm.;
n25D 1.4979. The yield is
58–66 g. (
35–40% based on
lithium) (Note
4) and (Note
5).