Organic Syntheses, CV 3, 194
Submitted by C. E. Kaslow and W. M. Lauer.
Checked by C. F. H. Allen and H. W. J. Cressman.
1. Procedure
In a
500-ml. flask, to which is attached an
air condenser whose open end is protected by absorbent cotton or calcium chloride in a drying tube, are mixed
119 g. (0.75 mole) of 4-methylcarbostyril (p. 580) and
138 g. (82.5 ml., 0.9 mole) of freshly distilled phosphorus oxychloride. The mixture is maintained at 80–85° in a
water bath for about 15 minutes until most of the solid has dissolved, and then it is warmed carefully for an additional 15 minutes on a
wire gauze until solution is complete. The hot reaction mixture is poured into 1 l. of water containing 1 kg. of cracked ice.
The
2-chlorolepidine is extracted, using two
750-ml. portions of ether (Note
1). The extract is shaken with two 200-ml. portions of water and then dried over
50 g. of potassium carbonate. After removal of the
ether, the residual oil is distilled from a
200-ml. modified Claisen flask. The colorless distillate boils at
132–135°/3 mm. and weighs
118–122 g. (
89–92%). The distillate is melted if necessary and poured into
250 ml. of petroleum ether (b.p.
40–50°); the solution is then chilled in a freezing mixture; the crystals are filtered by suction and dried in a
vacuum desiccator over paraffin. The snow-white
2-chlorolepidine melts at
58–59° and weighs
114–118 g. (
86–89%).
2. Notes
1. An additional
5–8 g. of slightly colored material can be secured by neutralizing the aqueous solution with
200 g. of sodium carbonate, extracting with
500 ml. of ether, and distilling. The total yield of distilled product then amounts to
125–130 g. (
95–97%).
3. Discussion
This preparation is referenced from:
Copyright © 1921-2002, Organic Syntheses, Inc. All Rights Reserved