Dibenzoylmethane

C6H6C(OCH3) = CHCOC6H3+2NaBr+CH3OH C6H5C(OCHa) = CHC0C6Hs+H20 -  

C6HsC(OH) =CHCOCsHfl+CH3OH C6HsC(OH) = CHCOC6Hs C6HsCOCH2COC6Hs 

If ordinary methyl alcohol is used, the yields agree with the lower figures. The diketone is also contaminated by an oily substance that persists through several recrystallizations. The presence of water favors the elimination of bromine and regeneration of the unsaturated ketone. 

The use of steel spatulas should be avoided, as traces of iron salts cause the product to be of a reddish color. This can be removed either by a vacuum distillation, or by dissolving in concentrated sulfuric acid and reprecipitating by pouring the acid solution upon cracked ice. 

The mother liquor contains only 2-3 g. more of the diketone, which can be separated as the copper derivative by shaking an ethereal extract with a saturated aqueous solution of copper acetate, 

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Dibenzoylmethane (l,3-diphenyl-l,3-propanedione) [120-46-7] M 224.3, m 80 . Crystd from pet ether or MeOH. 

Note The reagent can be employed on silica gel layers, which may also be impregnated, for example, with 8-hydroxyquinoline or dibenzoylmethane [3] or with 2,2 -dipyridyl or iminodiacetic acid [4] or on cellulose layers. 

Disubstituted furans are available from the combination of P-dicarbonyl compounds with bromoacetaldehyde diethyl acetal (44). For example, dibenzoylmethane (45) reacts with acetal 44 to furnish 2,3-disubstituted furan 46 in 77% yield. This two-... 

Krivun, Shian, and Dorofeenko condensed acetylacetone or dibenzoylmethane with various ketones (acetone, acetophenone, acetothienone, 1-acetylnaphthalene, or 5-acetylacetaphthene) and obtained pyrylium salts in 10-20% yield in the presence of perchloric acid. 

Spectrophotometric methods may often be applied directly to the solvent extract utilising the absorption of the extracted species in the ultraviolet or visible region. A typical example is the extraction and determination of nickel as dimethylglyoximate in chloroform by measuring the absorption of the complex at 366 nm. Direct measurement of absorbance may also be made with appropriate ion association complexes, e.g. the ferroin anionic detergent system, but improved results can sometimes be obtained by developing a chelate complex after extraction. An example is the extraction of uranyl nitrate from nitric acid into tributyl phosphate and the subsequent addition of dibenzoylmethane to the solvent to form a soluble coloured chelate. 

Diaminomaleonitrile (1) condenses with acetylacetone to give the 6//-l,4-diazepine 2.186 The reaction does not succeed with dibenzoylmethane or /J-oxo esters. 

Diketonate cobalt(III) complexes with alkyl peroxo adducts have been prepared recently and characterized structurally, and their value in hydrocarbon oxidation and olefin epoxidation examined.980 Compounds Co(acac) 2(L) (O O / - B u) with L = py, 4-Mepy and 1-Meim, as well as the analog of the first with dibenzoylmethane as the diketone, were prepared. A distorted octahedral geometry with the monodentates cis is consistently observed, and the Co—O bond distance for the peroxo ligand lies between 1.860(3) A and 1.879(2) A. 

Few Ni4 complexes with a cubane-like structure and four triply bridging //3-l,l,l-N3 ligands symmetrically bound to three Ni11 ions have been discovered (886),2135,2156 but magnetic data are only reported in the case of [Ni4(dmb)4(EtOH)4(//3-l,l,l-N3)4] (dbm = dibenzoylmethane).2135,2136 Its magnetic behavior was well reproduced by a model with a single 7 = +11.9cm 1. 

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