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Org. Synth. 1948, 28, 6
DOI: 10.15227/orgsyn.028.0006
9-ACETYLPHENANTHRENE
[Ketone, methyl 9-phenanthryl]
Submitted by Joseph E. Callen, Clinton A. Dornfeld, and George H. Coleman1.
Checked by Robert E. Carnahan and Homer Adkins.
1. Procedure
A dry 12-l. three-necked flask is equipped with an efficient motor-driven stirrer (Note 1), a nitrogen inlet tube, a large Allihn condenser, and a 1-l. separatory funnel. Both the condenser and the funnel are provided with calcium chloride drying tubes. To the flask is added 146 g. (6 gram atoms) of magnesium turnings (Note 2), and nitrogen gas, first bubbled through concentrated sulfuric acid, is passed in to displace the air. During the reaction the nitrogen atmosphere is maintained. The magnesium is covered with 200 ml. of anhydrous ether, and a few milliliters of a solution of 852 g. (6 moles) of methyl iodide in 1 l. of anhydrous ether is added from the separatory funnel. The reaction starts spontaneously, and then the remainder of the methyl iodide solution is added slowly. When the reaction is complete (Note 3), 4 l. of dry benzene is added, a condenser is arranged for downward distillation, and about 1.2 l. of solvent is distilled (Note 4). The condenser is changed to a reflux position, 609 g. (3 moles) of 9-cyanophenanthrene (p. 212) is added quickly through a powder funnel, and the mixture is heated and stirred under reflux for 3 hours. It is then cooled in an ice bath to 0°, 3 l. of cold 6 N hydrochloric acid is slowly added (Caution!) from a separatory funnel with stirring, and the mixture is refluxed for 6 to 8 hours (Note 5).
After cooling, the layers are separated, the organic layer is washed with dilute sodium bicarbonate solution and placed in a flask equipped for distillation, and the solvent is distilled The oily residue is transferred while still warm to a 1-l. Claisen flask, and the product is distilled under reduced pressure; b.p. 190–200°/2.5 mm. (168–170°/1 mm.). The yield is 400–430 g. (61–65%). The distilled ketone is recrystallized once from ethanol (1.5–2 l.) to yield 345–390 g. (52–59%) of 9-acetylphenanthrene of m.p. 73–74°.
2. Notes
1. If a 12-l. three-necked flask is not available, a three-way adapter tube may be used in making the necessary connections. Although a mercury seal may be used, a glycerol-rubber tube seal is adequate.
2. The checkers operated on one-tenth the scale specified.
3. In several runs the Grignard reagent was filtered at this point, but the improvement in yield was not appreciable.
4. The addition of benzene and distillation of part of the solvent raises the reaction temperature.
5. The oily layer of ketimine hydrochloride usually dissolves during 6 hours' refluxing.
3. Discussion
The method described above is a modification of that of Bachmann and Boatner.2 9-Acetylphenanthrene has also been obtained by a Claisen condensation of methyl phenanthrene-9-carboxylate with ethyl acetate followed by scission of the resulting phenanthroylacetic ester,3 by the reaction of 9-phenanthrylmagnesium bromide with acetyl chloride,4 and by dehydrogenation of 9-acetyl-1,2,3,4-tetrahydrophenanthrene by heating with sulfur.5

References and Notes
  1. Work done under contract with the Office of Scientific Research and Development.
  2. Bachmann and Boatner, J. Am. Chem. Soc., 58, 2098 (1936).
  3. Mosettig and van de Kamp, J. Am. Chem. Soc., 55, 3445 (1933).
  4. Miller and Bachman, J. Am. Chem. Soc., 57, 768 (1935).
  5. Bachmann and Struve, J. Org. Chem., 4, 476 (1939).

Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

ethanol (64-17-5)

sulfuric acid (7664-93-9)

hydrochloric acid (7647-01-0)

Benzene (71-43-2)

ethyl acetate (141-78-6)

ether (60-29-7)

acetyl chloride (75-36-5)

sodium bicarbonate (144-55-8)

magnesium,
magnesium turnings (7439-95-4)

nitrogen (7727-37-9)

sulfur (7704-34-9)

Methyl iodide (74-88-4)

9-Acetylphenanthrene,
Ketone, methyl 9-phenanthryl (2039-77-2)

9-Cyanophenanthrene (2510-55-6)

methyl phenanthrene-9-carboxylate

9-phenanthrylmagnesium bromide

9-acetyl-1,2,3,4-tetrahydrophenanthrene

ketimine hydrochloride