L,3-Diphenyl-2-propanone

Dibenzyl ketone (l,3-diphenyl-2-propanone) [102-04-5] M 210.3, m 34.0 . Fractionally crystd from its melt, then crystd from pet ether. Stored in the dark. 

Determination of concentration. Two laboratories3 recommend l,3-diphenyl-2-propanone tosylhydrazone (m.p. 185-186° dec.) for determination of The concentration of RLi in THF solutions. The dianion of the tosylhydrazone has an intense orange color. 

Balaban, Mateescu, and Nenitzescu,495 diacylatcd l,3-diphenyl-2-propanone (213, R = Ph) to 3,5-diphcnyl-4-pyrones (215), the former with acetic and polyphosphoric acids, the latter with acetyl chloride and aluminum chloride. This reaction follows the usual course of ketone acylation,13 235, z36> 409 and has been studied in detail by several research groups in the last 3 years.102 107 A similar reaction takes... 

The longest continuous chain contains three carbons, and C-2 is the carbon of the carbonyl group. The substitutive lUPAC name for this ketone is l,3-diphenyl-2-propanone or 1,3-diphenylpropan-2-one. 

Experiments to synthesize six membered heterocycles starting from both l,3-diphenyl-2-propanone phenylhydrazone and 2-ethoxy-l-naphth-aldehyde semicarbazone, which are unable to form five membered rings, faded [692]. 

Pyrones. A soln. of l,3-diphenyl-2-propanone, acetic acid, and polyphosphoric acid refluxed 1.5 hrs. at 140-150 crude 2,6-dimethyl-3-5-diphenyl-4H-pyran-4-one, Y 76%.— This reaction is a simple route to 4-pyrones and, in certain cases, to benzoIa]fluorcnones. F. e. s. R. L. Letsinger and J. D. Jamison, Am. Soc. 83, 193 (1961). 

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