Diphenyl triketone

Diphenyl Triketone Hydrate A solution of 34.3 g. (0.42 mole) of fused sodium acetate in 142 cc. of hot glacial acetic acid is prepared in a i-l. round-bottomed flask 72.4 g. (0.19 mole) of dibenzoyldibromomethane is added, and the mixture is refluxed until the precipitation of sodium bromide ceases (one and one-half to two hours). The mixture is then cooled to room temperature and diluted with 150-200 cc. of water with constant shaking to dissolve the inorganic salt and to precipitate the triketone hydrate, which separates as a white, curdy mass (Note 4). This is separated by filtration, washed well with water, and dried in an oven at 60°. The melting point varies from 65 to 90°, depending upon the extent of dehydration that occurs during the drying operation. The yield is 41.5 g. (86 per cent of the theoretical amount based on the dibenzoyldibromomethane). 

Diphenyl Triketone The 41.5 g. (0.16 mole) of triketone hydrate is distilled in vacuum from a Claisen flask heated by means of a sand bath. A distilling flask is used as a receiver, and no condenser is necessary. The neck of the receiving flask must be warmed, however, to prevent clogging of the apparatus by crystallization of the distillate. The anhydrous triketone distils at 174-176°/2 mm. as a reddish oil that solidifies to a light yellow, crystalline mass. This is dissolved in 70 cc. of hot ligroin (b.p. 90-120°) it separates on cooling in light yellow needles which melt at 68 70°. The yield is 35 g. (91 per cent of the theoretical amount based on the triketone hydrate 59 per cent based on the dibenzoylmethane) (Note 5). 

The bromine should be dried by washing it with concentrated sulfuric acid. 

If the solvent is removed by heat at ordinary pressure, there is a decrease both in the yield and the purity of the product. 

If the recrystallization is omitted, a lower yield of the triketone hydrate is obtained. 

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Diphenyl-triketon verliert, wie eine Anzahl anderer oc-Poly-carbonyl-verbindungen unter dem EinfluB verschiedener basischer oder sauerer Katalysatoren CO oder C02 und geht dabei in Benzil oder Benzoin iiber. Roberts, Smith und Lee (165) untersuchten nun mit Hilfe von Di-phenyl-triketon- [1 -i4C], ob dabei die mittlere oder eine dem Kern be-nachbarte Carbonylgruppe verloren geht. 

Reactions with Phenanthraquinone, 9-Arylxanthenes, and Diphenyl Triketone. J. Chem. Soc. 997 (1947). 

Diphenyl triketone, 13, 38 Diphenyl triketone hydrate, 13, 39 Disulfide, 12, 76... 

C2sHi9BrN203, p-Bromobenzeneazotribenzoylmethane, 31B, 50 C2BH20N2O3, Diphenyl triketone sym-benzoylphenylhydrazone, 38B, 87 C2BH2oN203f Phenylazotribenzoylmethane, 38B, 89 C36Hs8N2r 2,2 ,4,4 ,6,6 -Hexa-t-butylazobenzene, 46B, 53... 

Diaryl triketones do not show the same reactivity as their dialkyl counterparts. This is illustrated by the fact that 19-hr irradiation through Pyrex using the full spectrum of a 1000-W, high-pressure, mercury-vapor lamp was required for 90% disappearance of 250 mg of diphenyl triketone (13) in degassed p-xylene solution. The major products isolated were p,p -dimethylbibenzyl, benzaldehyde, and p-methyl-benzyl phenyl ketone in addition, minor amounts of oxidation products such as p-methylbenzyl benzoate were identified, as well as traces of benzil. Quantum yields for the disappearance of 13 at 436 nm in degassed or air-saturated p-xylene solutions were about 3 x 10 k nearly identical values were obtained... 

Schonberg, A. and Mustafa, A., Photochemical reactions in sunlight. Part Xll. Reactions with phenanthraquinone, 9-arylxanthene, and diphenyl triketone, J. Chem Soc., 997,1947. 

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