Here follows several japanese syntheses of phenylacetone, as summarized in Chemical Abstracts.
CA Nomenclature note: Analogous to the shorthand Ac for Acetyl (Me[/sub]CO-), Bz is short for Benzoyl (PhCO-) and not Benzyl (PhCH2-)
Reaction of ?-halocarbonyl compounds with Grignard reagents. II. Reactions of ?-chloroacetophenones.
Teiichi Ando, CA 54. 449215 [Yuki Gosei Kagaku Kyokaishi 17, 777-82 (1959)]
Reactions of some ?-chloroacetophenones (RCOCH2Cl) with Grignard reagents in ratio of 1:1 and 1:2 were studied and compared (cf. CA 53, 17971d)
Ratio of 1:1: To a Grignard reagent prepd. from 17.3g PhBr, 2.7 g Mg, and 100 mL Et2O was dropped 15.6g ?-chloroacetophenone (I) in 100 mL C6H6 at -3°C to 0°C, the mixt. stirred at 0°C for 30 min, concd. till the bp of the mixt. increased to 72°C, and then refluxed 4 hrs., cooled, decompd. with ice and HCl, and the sepd. org. solvent layer distd. to give 40% deoxybenzoin, bp 160-170°C/6 mmHg, mp 55-56°C (MeOH); semicarbazone mp 147-148°C. Similarly were carried out the following reactions. I with MeMgI, 45% phenylacetone (101-104°C/23mmHg; semicarbazone m. 189-190°C). ?-chloro-p-fluoroacetophenone (III) with MeMgI, 41% p-fluorophenylacetone (120-130°C/30mmHg; semicarbazone mp 199-200°C).
Ratio of 1:2: I (7.7g) in 100 mL C6H6 was treated with Grignard reagent prepd. from 17.3g PhBr, 2.7g Mg, and 100 mL Et2O to give 44% 1,2,2-triphenylethanol, mp 87-94°C (ligroin), and 1.8g triphenylethylene, bp10 200-120°C, mp 67-68°C (EtOH). Similarly were carried out the reaction between III with p-F-PhMgBr. 72% tris(p-fluorophenyl)ethylene (bp 195-205°C/12 mmHg, mp 71-72°C).
These results showed that ketones were obtained when the molar ratio of the reactants was 1:1, and 1,1,2-trisubstituted ethanols were obtained when that ratio was 1:2. Based on these experimental results and on the conception of migratory aptitude of atomic groups, the mechanism of the reaction was also discussed.
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Reduction of 1-phenyl-1,2-propanedione. I. Synthesis of phenylacetone.
Genshun Sunagawa and Kichihei Okuda, CA 46, 11146a(1952) [J. Pharm. Soc. Japan 72, 117-118 (1952)]
Catalytic reduction of 18.5 g BzAc (I) in 40 mL MeOH with PtO2 gives 11.9 g. PhCH(OH)CH(OH)Me (II) mp 92-93°C; catalytic reduction of a mixt. of I and MeNH2 in MeOH with PtO2 gives dl-ephedrine·HCl, and the mother liquor taken up with ether and distd. gives II.
Refluxing 20 g II with 200 g 20% H2SO4 5-7 h, taking up with ether, and distg. give 13g PhCH2Ac; semicarbazone, mp 190-6°C.
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Phenylethynylcarbinol and its derivatives. II. Synthesis of phenylacetone
Ichiro Hirao, Chem. Abs. 10534c (1954) [J. Chem Soc. Japan, Ind. Chem. Sect. 56, 265-266(1953)]
Commercial PhCH(OH)CCH was hydrated with H2SO4 to PhCH(OH)COCH3, which was hydrogenated with Raney-Ni catalyst by H2 of 50 atms. in an autoclave at room temp. The white crystals obtained correspond to 1,2-dihydroxy-1-phenylpropane (I) of mp 91-92°C; yield, 95% PhCH2Ac was prepd. by heating of I with H2SO4, oxalic acid, H3PO4, etc.; yield approx. 73%.
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Synthesis of phenylacetone
Keiichi Shishido and Shigeru Kukita
CA 42, 6339g [J. Soc. Chem. Ind. Japan 48, 34(1945)]
A Grignard reagent prepd. from 6g Mg, 1.70 mL anhyd. ether, a small crystal of I2 and 32 g PhCH2Cl was dropped slowly into 20g AcCl in 150 mL ether, kept at -10°C to -15°C, and the product treated with ice-cooled concd. HCl, extd. with ether, neutralized, and distd. under 9 mmHg at 87-93°C, giving 27% PhCH2Ac, mp 188.5-189°C from alcohol).
This one is a little fishy - the mp data makes no sense, as P2P is a liquid. It does however jive with the mp of P2P semicarbazone, which is mentioned in two of the above abstracts as well. I wonder if it's a typo or a mistaken product?