Organic Syntheses, CV 2, 451
Submitted by W. W. Hartman, J. R. Byers, and J. B. Dickey.
Checked by Louis F. Fieser and J. T. Walker.
1. Procedure
In a
3-l. round-bottomed flask, fitted with a
reflux condenser, are placed
100 g. (0.435 mole) of 1-nitro-2-acetylaminonaphthalene (p. 438) and a solution of
112 g. (2.8 moles) of sodium hydroxide in 2.7 l. of water (Note
1). The mixture is boiled until
ammonia is no longer evolved (six to seven hours). The solution becomes deep red in color. It contains suspended crystals of
sodium nitronaphthoxide; these are dissolved by the addition of 1 l. of hot water. The small amount of insoluble material is removed by filtration, washed with hot water until the washings are colorless, and then discarded although it contains a little
nitronaphthylamine. The combined washings and filtrate are made acid by adding
500 cc. of glacial acetic acid. The
nitronaphthol precipitates as small, bright yellow crystals which are filtered on a
10-cm. Büchner funnel, washed with water, and dried. The yield of material melting at
101–103° is
76–81 g. (
92–98 per cent of the theoretical amount).
The product is purified by recrystallization from
500 cc. of methyl alcohol containing 5 cc. of concentrated hydrochloric acid. The first crop of crystals amounts to
60 g. and melts at
103–104°. The mother liquors are concentrated to 150 cc., and a second crop weighing
12–13 g. is collected. The total yield of recrystallized material is
72–73 g. (
88–89 per cent of the theoretical amount).
2. Notes
1. This concentration of alkali was found to be very satisfactory. The hydrolysis takes place rather rapidly at first when stronger alkali is used, with the precipitation of the sodium salt which forms a thick paste and causes bumping. When more dilute alkali is used, much more time is required to complete the hydrolysis.
3. Discussion
The method on which this procedure is based has been described by Andreoni and Biedermann and by others.
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