Organic Syntheses, CV 3, 20
Submitted by W. W. Hartman and L. J. Roll.
Checked by A. H. Blatt and Lewis Rothstein.
1. Procedure
In a
1-l. flask arranged for steam distillation (Note
1),
50 g. (0.31 mole) of isonitrosopropiophenone (Org. Syntheses, 16, 44;
Coll. Vol. 2, 363) and
500 g. of 10% sulfuric acid are mixed, and the mixture is distilled with steam until about 2 l. of distillate is collected. During the distillation the flask is heated so that the volume of the reaction mixture is kept roughly constant. The distillation requires about 6 hours, and at the end of this time the liquid in the flask is clear (Note
2).
The lower, yellow layer of diketone in the distillate is separated; the water layer is then saturated with salt and extracted with
ether, one 80-ml. and two 25-ml. portions being used for each liter of the aqueous solution. The
ether extracts are combined with the diketone proper and dried over
sodium sulfate. The
ether is removed on the
steam bath, and the residual material is distilled from a
Claisen flask under reduced pressure.
Acetylbenzoyl is collected at
114–116°/20 mm. (Note
3). The yield is
30–32 g. (
66–70% of the theoretical amount) (Note
4).
2. Notes
1. A spray
trap should be placed between the flask and the condenser; otherwise some isonitrosoketone will be carried over. The checkers used a "Kjeldahl Connecting Bulb, Cylindrical Type," illustrated as item 2020 in the Pyrex Catalog, LP–34, for 1954.
2. On being cooled, the reaction mixture deposits
3–7 g. of the
dioxime of acetylbenzoyl, m.p.
234–236° dec.
1
3. Other boiling points reported for
acetylbenzoyl are
216–218°,
164–165°/116 mm., and
102–103°/12 mm.
4. According to the submitters the reaction can be carried out with about the same percentage yields using five times the amounts of material specified above.
3. Discussion
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