Org. Synth. 1943, 23, 1
DOI: 10.15227/orgsyn.023.0001
ACETYLBENZOYL
[1,2-Propanedione, 1-phenyl-]
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.
13.
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
Acetylbenzoyl has been prepared by dehydrogenation of
acetylphenylcarbinol over
copper at 350°;
2 by oxidation of
1-methyl-2-phenylethylene glycol;
3 by action of
amyl nitrite on
isonitrosopropiophenone;
4 and by acid hydrolysis of
isonitrosopropiophenone5 or of
isonitrosobenzyl methyl ketone.
6 The last-named reaction is reported to furnish quantitative yields of
acetylbenzoyl, but the starting material is not easily accessible. Treatment of
propiophenone with
amyl nitrite (2 moles) without isolating the isonitroso compound has been mentioned as a method of preparing
acetylbenzoyl,
4 but the yield of diketone is much better when the isonitroso compound is isolated.
7 Acetylbenzoyl also has been prepared by the oxidation of
phenyl acetone with
selenium dioxide.
8
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
dioxime of acetylbenzoyl
sulfuric acid (7664-93-9)
ether (60-29-7)
sodium sulfate (7757-82-6)
copper (7440-50-8)
selenium dioxide (7446-08-4)
amyl nitrite (463-04-7)
Propiophenone (93-55-0)
phenyl acetone (103-79-7)
ISONITROSOPROPIOPHENONE
1,2-Propanedione, 1-phenyl- (579-07-7)
1-methyl-2-phenylethylene glycol
Acetylbenzoyl (579-07-7)
acetylphenylcarbinol
isonitrosobenzyl methyl ketone
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