A
1-l. three-necked round-bottomed flask is placed on a
steam bath and fitted with a
stirrer,
reflux condenser, and
dropping funnel. A solution of
181 g. (1 mole) of ethyl α-bromopropionate in
200 ml. of benzene is placed in the flask (Note
1), and
148 g. (2.1 moles) of pyrrolidine (Note
2) is added slowly with stirring at such a rate that the solvent refluxes gently. When the addition is complete (about 1 hour is required), the mixture is heated under reflux for 1 hour. After being cooled, the mixture is poured into about 500 ml. of ice water and acidified with dilute
hydrochloric acid. The aqueous layer is separated, washed once with
ether, and made strongly basic with cold
40% sodium hydroxide solution. The basic ester is extracted with four
200-ml. portions of ether. The
ether extracts are combined, washed with 100 ml. of water, and dried over anhydrous
potassium carbonate. The drying agent is removed by filtration and the
ether by distillation. The residue is distilled under reduced pressure through a
short fractionating column; b.p.
84°/12 mm. (
95–96°/19 mm.,
99.5–100.5°/23 mm.,
104–105°/30 mm.);
nD20 1.4478,
nD25 1.4450;
d425 0.9724. The yield is
137–156 g. (
80–91%).