Benzoyl-acetone

Complications often arise in the use of 1,3-diketones under the above reaction conditions. This is primarily due to the lack of regioselectivity with regard to formation of the intermediate thioacetal. However, when benzoyl acetone derivatives are employed, the thioketal forms preferentially with the aromatic ketone. ... 

With unsymmetrical diketones the orientation of the reaction is again controlled by the reaction of the most reactive carbonyl group with the 5-position of the pyrimidine ring. Thus, benzoyl acetone and 6-aminouraoil gave 5-methyd-7-phenylpyrido[2,3-d]pyrimidine-2,4-(lH,3iI)-dione (71), in preference to the 5-phenyl isomer (72). ... 

Organic synthesis 53 [OS 53] Addition of benzoyl acetone to ethyl propiolate [8]... 

The reduction of pertechnetate with concentrated hydrochloric acid finally yields the tetravalent state, and no further reduction to the tervalent state takes place. Therefore, the tervalent technetium complex has usually been synthesized by the reduction of pertechnetate with an appropriate reductant in the presence of the desired ligand. Recently, the synthesis of tervalent technetium complexes with a new starting complex, hexakis(thiourea)technetium(III) chloride or chloropentakis(thiourea)technetium(III) chloride, has been developed. Thus, tris(P-diketonato)technetium(III) complexes (P-diketone acetylacetone, benzoyl-acetone, and 2-thenoyltrifluoroacetone) were synthesized by the ligand substitution reaction on refluxing [TcCl(tu)5]Cl2 with the desired P-diketone in methanol [28]. 

Clausius-Clapeyron equation to calculate the value of A// ,subUmation for benzoyl-acetone. 

Fig. 4.6 Distribution ratios calculated by Eq. (4.22) for acetylacetone (HAA) benzoyl-acetone (HBA) bezoyltrifluoroacetone (HBTFA) and oxine (8-hydroxyquinoline, HOQ), in the system 0.1 M NaC104 /CCE, using the following constants. (From Refs. 

Cyclization of the diamidine 154 with acetyl- or benzoyl-acetone (153) gave l,2,4-triazolo[l,5-a]pyrimidine (156) via the formation of 155 (66CB2237 79AP1003). Alternatively, 156 can be prepared by the reaction of 153 with the diaminotriazole 157 (66CB2237) (Scheme 29). 

Aromatic esters may be used to aroylate the dianions derived from 1,3-diketones by reaction with potassium amide (60JOC538). Not only are acetyl and benzoyl acetones suitable for reaction, but alicyclic diketones and 2-hydroxyacetophenone are also acceptable. Cycliz-ation of the triketones occurs in cold sulfuric acid, presumably via the enolic form and the hemiacetal (Scheme 132). 

It is also possible [637] to bracket the donor triplet state by the proper choice of ligand, and a selective excitation of one of the resonance levels of Eu3+ ion can be effected. The fluorescence spectra of benzoyl-acetone and dibenzoylmethide complexes of Eu3+ show transitions from... 

Selenium acetylacetone may be converted into selenium benzoyl-acetone by dissolving it in a warm solution of benzoylacetone in chloroform in the presence of a trace of sodium hydroxide, the resulting selenium frisbenzoylacetone being converted into selenium benzoylacetone by boiling with alcohol. 

Method I.—6 gms. (1 mol.) of fresh dry sodium ethylate (see p. 509) are added to 20 gms. (excess) of dry ethyl acetate under cooling by water. After 15 minutes, 10 gms. (1 mol.) of acetophenone are added the separation of the sodium salt of benzoyl acetone immediately begins. A little dry ether is added, and in 4 hours the sodium compound is filtered off, washed with ether, air-dried, dissolved in cold water, and the solution acidified with acetic acid. Benzoyl acetone separates. 

Yield.—66% theoretical (10 gms.). Colourless crystals insoluble in water M.P. 61° gives a deep violet coloration with ferric chloride and a bluish-green crystalline precipitate of copper benzoyl acetone with alcoholic copper acetate. This shows the compound to be tautomeric, a little of the enol form being present at ordinary temperatures. The acidity of the hydroxyl group in the enol form is not so marked as it is in the case of the hydroxymethylene compounds nevertheless, the metallic salts of benzoyl acetone and such di-ketones are remarkably stable, and on account of their great crystallising power have been used for the determination of the valency and atomic weight of the rare elements. They are also of importance in the modern theory of co-ordination. (C., 1900,1., 588 B., 34, 2584.)... 

Benzoic ester and acetone yield benzoyl-acetone. CjHj.COOCjHj + CH3.CO.CH3 - CjHs.CO.CH3.CO.CH3 + CsHjOH... 

Benzoyl acetone from acetic ester and acetophenone ... 

Another case of quinoline formation is the condensation of benzoyl acetone and aniline, resulting in y-plieny l-qnirialdine ... 

As it is well known, sensitization of Ln-centered luminescence can be achieved via an intramolecular energy transfer upon excitation of organic ligands, instead of using direct excitation of the weak Lnm absorption bands. This phenomenon now called antenna effect or luminescence sensitization has first been observed in 1942 by Weissman for europium(III) complexes formed with salicylaldehyde and with /3-diketonates, more particularly benzoyl-acetonate (ba, 48a), dibenzoylmethanate (dbm, 48b) and wieta-nitrobenzoylacctonatc (47a, fig. 41) (Weissman, 1942). 

Up to about the 1960 s, elemental analysis coupled with absorption spectra and infrared spectra and X-ray crystallography were the primary methods used in the studies of complexes. Later on with the developments in nuclear magnetic resonance (NMR) spectroscopy, especially multinuclear NMR, this technique has been invariably used in the studies of structural features of lanthanide complexes. To illustrate these points some references to literature are herein pointed out. The studies on the rare earth 1,3-diketonates, where 1,3-diketones are acetyl acetone, benzoyl acetone, dibenzoyl methane and 2-thienoyl tri-fluoroacetone totally relied on elemental analysis, UV-Vis and IR spectra to establish the nature of the complexes [89]. The important role played by X-ray crystallography in the elucidation of the structures of lanthanide complexes has been extensively discussed in Chapter 5 and the use of this technique goes as far back as the 1960 s. Nevertheless it continues to play a major role in the studies of lanthanide complexes. 

A solution of 3.5 g. (0.0096 mol) thallium (I) benzoyl-acetonate in 20 ml. of benzene is mixed with 1.64 g. (0.0048 mol) of diphenyltin dichloride in 10 ml. of benzene. Thallium (I) chloride precipitates immediately and is separated by filtration. The product is most easily collected by evaporating the solvent. The yield is quantitative. For recrystallization the product is dissolved in 50 ml. of benzene, and 50 ml. petroleum ether (b.p. 90 to 110°) is added. The yield is 1.4 g. (50%). (The checkers report that it is necessary to add another volume of petroleum ether and to hold the solution at least overnight at 10° to obtain 50% yield.) The rest of the crystals can be recovered by partial evaporation of the solvent. The pure product melts with decomposition at 181°. (The checkers report 185.5 to 187°.) Anal. Calcd. for C32H2804Sn C, 64.52 H, 4.74. Found C, 65.19 H, 4.93. 

Von den Chelatbildnern, die zu 6-Ring-Chelaten ffihren, sind weitaus die wichtigsten die (3-Diketone, speziell Acelylaceton(I), Benzoyl-aceton(II), Dibenzoylmethan(III) und Thenoyltriftuoraceton(IV)... 

Diketones. Beta-diketones such as acetylacetone, benzoyl-acetone, and isopropyltropolone are well known for their applications in analytical extraction of actinides. These compounds are weak acids due to tautomerization thus they can act as cation exchange extractants. Trivalent actinide [M(III)] extraction by the reagent (HA) at low aqueous acid concentration where the compound behaves both as cation exchanger and coordinator probably follows the reaction... 

New complexes containing azo- and hydrazinato-derivatized Schiff base ligands298 375 continue to be used for the analytical determination of vanadium.376 The vanadium complex was characterized for the Schiff base derived from the condensation reaction of benzoyl acetone and Girard s reagent P.377 Azophenolates of mononuclear and mixed valence dinuclear species have been reported.378 Naphthanol- or quinolinol-derivatized ligands prefer to chelate iron over vanadium.379... 

Claisen, L. Zu den O-Alkylderivaten des Benzoyl-acetons und den aus ihnen entstehenden Isooxazolen. Ber. dtsch. chem. Ges. 1926, 59, 144-153. 

On short heating with excess acetyl- or benzoyl-acetone, hydrochlorides of 3,4-diamino-l, 2,4-triazoles are converted to l-aminotriazolo[2,3-a]pyri-... 

Hz) have been isolated, including octahedral Co(R R C=N—NHCOR )X2 (R = H, Me, or C5H10 R = Ph, p-MeOPh, or Me R = Ph, o-HOPh, or p-MeOPh X = NO3, Cl, Br, or SCN) and dimeric five-co-ordinate Co(R R C= NN=C0R )2- Formation constants have been reported for reactions between M bipy (M = Co, Ni, or Cu) and monoanions of the ) -diketonates acac, benzoyl-acetone, dibenzoylmethane and dipivaloylmethane. Cobalt ions have been extracted from an ion exchange resin by formation of Co(tta)2Bn (Htta = 2-thenoyl-trifluoroacetone, B = py base) and the synergistic effect decreased in the order py > > y-pic > a-pic > y-colidine isoquinoline > piperidine > 4-benzoyl-... 

With unsymmetrical diketones the orientation of the reaction is again controlled by the reaction of the most reactive carbonyl group with the 5-position of the pyrimidine ring. Thus, benzoyl acetone and... 

RCOCH3 + (CH3C0)20 BF3 > RCOCH2COCH3 + ch3cooh For example, Meerwein and Vossen773 describe the preparation of benzoyl-acetone (1-phenyl- 1,3-butanedione) as follows ... 

Acetophenone (20 g) and acetic anhydride (34 g, 2 moles) are mixed and boron trifluoride is led in, with ice-cooling, to saturation. 4The mixture becomes almost filled with yellowish crystals and is poured into a solution of crystalline sodium acetate (45 g) in water (100 ml) and distilled in steam. A small amount of oil first distils and is followed by the benzoyl-acetone which tends to solidify in the condenser. This product is taken up in ether, washed with sodium hydrogen carbonate solution, dried over sodium sulfate, and distilled in a vacuum. The yield is 83.3% (22.5 g). 

Claisen, L. (1926) Zu den 0-alkylderivaten des benzoyl-acetons und den aus ihnen entstehenden isooxazolen. Ber. Dtsch. Chem. Ges. 59 144-153. 

In hquid state, the percentage of enol forms in acetylacetone and benzoyl acetone is 80% and 89%, respectively. The enol form of benzoyl acetone gets further stabilization, besides the intramolecular hydrogen bonding shown above for acetyl acetone, due to conjugation of the carbon-carbon double bond with the phenyl group (Scheme 3.49). 

Scheme 3.49 Keto-enol equilibrium in benzoyl acetone.

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