In a
1-l. round-bottomed flask attached to a
Dean and Stark constant water separator (Note
1) which is connected to a
reflux condenser are placed
46.5 g. (45.5 ml., 0.5 mole) of redistilled aniline,
65 g. (63.5 ml., 0.5 mole) of commercial ethyl acetoacetate,
100 ml. of benzene, and
1 ml. of glacial acetic acid. The flask is heated in an oil bath at about 125°, and the water which distils out of the mixture with the refluxing
benzene is removed at intervals. Refluxing is continued until no more water separates (9 ml. collects in about 3 hours) and then for an additional 30 minutes. The
benzene is then distilled under reduced pressure, and the residue is transferred to a
125-ml. modified Claisen flask with an insulated column. The flask is heated in an
oil or metal bath maintained at a temperature not higher than 120° while the fore-run of
aniline and
ethyl acetoacetate is removed by distillation under reduced pressure, and at 140–160° during distillation of the product (Note
2). The yield of
ethyl β-anilinocrotonate boiling at
128–130° /2 mm.,
nD25 1.5770, is
78–82 g. (
76–80%).