Acetylacetone, acidity

Decant the liquid layer into a 2 5 litre flask, and dissolve the sodium derivative of acetylacetone in 1600 ml. of ice water transfer the solution to the flask. Separate the impiue ethyl acetate layer as rapidly as possible extract the aqueous layer with two 200 ml. portions of ether and discard the ethereal extracts. Treat the aqueous layer with ice-cold dilute sulphimic acid (100 g. of concentrated sulphiu-ic acid and 270 g. of crushed ice) until it is just acid to htmus. Extract the diketone from the solution with four 200 ml. portions of ether. Leave the combined ether extracts standing over 40 g. of anhydrous sodium sulphate (or the equivalent quantity of anhydrous magnesium sulphate) for 24 hours in the ice chest. Decant the ether solution into a 1500 ml. round-bottomed flask, shake the desiccant with 100 ml. of sodium-dried ether and add the extract to the ether solution. Distil off the ether on a water bath. Transfer the residue from a Claisen flask with fractionating side arm (Figs. II, 24, 4r-5) collect the fraction boiling between 130° and 139°. Dry this over 5 g. of anhydrous potassium carbonate, remove the desiccant, and redistil from the same flask. Collect the pure acetji-acetone at 134r-136°. The yield is 85 g. 

Nonanedione, another 1,3-difunctional target molecule, may be obtained from the reaction of hexanoyl chloride with acetonide anion (disconnection 1). The 2,4-dioxo substitution pattern, however, is already present in inexpensive, symmetrical acetylacetone (2,4-pentanedione). Disconnection 2 would therefore offer a tempting alternative. A problem arises because of the acidity of protons at C-3 of acetylacetone. This, however, would probably not be a serious obstacle if one produces the dianion with strong base, since the strongly basic terminal carbanion would be a much more reactive nucleophile than the central one (K.G. Hampton, 1973 see p. 9f.). 

Diethyl 3-oxoheptanedioate, for example, is clearly derived from giutaryl and acetic acid synthons (e.g. acetoacetic ester M. Guha, 1973 disconnection 1). Disconnection 2 leads to acrylic and acetoacetic esters as reagents. The dianion of acetoacetic ester could, in prin-ciple,be used as described for acetylacetone (p. 9f.), but the reaction with acrylic ester would inevitably yield by-products from aldol-type side-reactions. 

Br , citrate, CE, CN , E, NH3, SCN , S20 , thiourea, thioglycolic acid, diethyldithiocarba-mate, thiosemicarbazide, bis(2-hydroxyethyl)dithiocarbamate Acetate, acetylacetone, BE4, citrate, C20 , EDTA, E , formate, 8-hydroxyquinoline-5-sul-fonic acid, mannitol, 2,3-mercaptopropanol, OH , salicylate, sulfosalicylate, tartrate, triethanolamine, tiron... 

Acetylacetone, ascorbic acid, citrate, C20j, EDTA, F , H2O2, hydrazine, mannitol, NagP30io, NH2OH HCI, oxidation to molybdate, 8CN , tartrate, tiron, triphosphate... 

Th Acetate, acetylacetone, citrate, EDTA, F , SO , 4-sulfobenzenearsonic acid, sulfosalicylic... 

Chemical ingenuity in using the properties of the elements and their compounds has allowed analyses to be carried out by processes analogous to the generation of hydrides. Osmium tetroxide is very volatile and can be formed easily by oxidation of osmium compounds. Some metals form volatile acetylacetonates (acac), such as iron, zinc, cobalt, chromium, and manganese (Figure 15.4). Iodides can be oxidized easily to iodine (another volatile element in itself), and carbonates or bicarbonates can be examined as COj after reaction with acid. 

Anhydride manufactured by acetic acid pyrolysis sometimes contains ketene polymers, eg, acetylacetone, diketene, dehydroacetic acid, and particulate carbon, or soot, is occasionally encountered. Polymers of aHene, or its equilibrium mixture, methylacetylene—aHene, are reactive and refractory impurities, which if exposed to air, slowly autoxidize to dangerous peroxidic compounds. 

Substances that form carbanions, such as nitro compounds, hydrocyanic acid, malonic acid, or acetylacetone, react with vinyl ethers in the presence of water, replacing the alkyl group under mild conditions (245). 

Ketones with labile hydrogen atoms undergo enol acetylation on reaction with ketene. Strong acid catalysis is required. If acetone is used, isoptopenyl acetate [108-22-5] (10) is formed (82—85). Isopropenyl acetate is the starting material for the production of 2,4-pentanedione (acetylacetone) [123-54-6] (11). 

With active methylene compounds, the carbanion substitutes for the hydroxyl group of aHyl alcohol (17,20). Reaction of aHyl alcohol with acetylacetone at 85°C for 3 h yields 70% monoaHyl compound and 26% diaHyl compound. Malonic acid ester in which the hydrogen atom of its active methylene is substituted by A/-acetyl, undergoes the same substitution reaction with aHyl alcohol and subsequendy yields a-amino acid by decarboxylation (21). 

The intense reddish-brown color of the acetylacetone titanium complexes impart a yellow discoloration to white inks. This discoloration is accentuated when the inks are used to print substrates that contain phenol-based antioxidants. The phenoHc compounds react with the organic titanate to form a highly colored titanium phenolate. Replacement of 0.25 to 0.75 moles of acetylacetone with a malonic acid dialkyl ester, such as diethyl malonate, gives a titanium complex that maintains the performance advantages of the acetyl acetone titanium complexes, but which is only slightly yellow in color (505). These complexes still form highly colored titanium phenolates. 

Cobalt(II) acetylacetonate [14024-48-7] cobalt(II) ethyUiexanoate [136-52-7] cobalt(II) oleate [14666-94-5] cobalt(II) linoleate [14666-96-7] cobalt(II) formate [6424-20-0], and cobalt(II) resinate can be produced by metathesis reaction of cobalt salt solutions and the sodium salt of the organic acid, by oxidation of cobalt metal in the presence of the acid, and by neutralization of the acid using cobalt carbonate or cobalt hydroxide. 

In 1888, Combes described condensation of 2,4-pentadione (acetylacetone) 5 with aniline 1 to provide enamine 6. Subsequent warming in sulfuric acid provided quinoline 7. An excellent study describing scope and limitations of the Combes reaction was published in 1928 by Roberts and Turner. The authors noted that the ease of... 

The mercaptals obtained by the acid catalyzed reaction of J3-ketoesters, e.g., ethyl acetoacetate, with methyl thioglycolate (73) undergo the Dieckmann cyclization with alcoholic potassium hydroxide at lower temperatures to give ethyl 3-hydroxy-5-methyl-2-thiophenecarboxylate (74) in 75% yield. ° Besides ethyl acetoacetate, ethyl a-ethylacetoacetate, ethyl benzoyl acetate, and ethyl cyclopentanonecarboxylate were also used in this reaction/ It is claimed that /8-diketones, hydroxy- or alkoxy-methyleneketones, or /8-ketoaldehyde acetals also can be used in this reaction. From acetylacetone and thioglycolic acid, 3,5-dimethyl-2-thiophenecarboxyl-ic acid is obtained. ... 

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. 

The reaction of 3-amino-4-cyanofurazan with (3-dicarbonyl compounds in the presence of catalytic amounts of nickel acetylacetonate (Ni(acac)2) gave labile enamines that on treatment with acetic acid afforded fused pyridines of type 100 in 80-95% total yields (Scheme 51) (94MC57). Eurther syntheses of furazano-pyridines can be found in the review by Sheremetev (99RCR137, 99UK154). 

A flask heated in an oil bath is fillad with 600 ml water and 60 g (1 mol) glacial acatic acid (or an equivalent quantity of diluted acetic acid). While stirring 235 g (1.1 mols) anhydrous p-aminobenzenesulfonamidoguanidine (or an equivalent quantity of a nonanhydrous product) and 122 g (1 mol) sodium acetylacetonate 100% purity (or an equivalent quantity of product of a lower purity) are introduced into the flask while stirring. 

Thenoyltrifluoroacetone(TTA), C4H3S,CO,CH2,COCF3. This is a crystalline solid, m.p. 43 °C it is, of course, a /1-diketone, and the trifluoromethyl group increases the acidity of the enol form so that extractions at low pH values are feasible. The reactivity of TTA is similar to that of acetylacetone it is generally used as a 0.1-0.5 M solution in benzene or toluene. The difference in extraction behaviour of hafnium and zirconium, and also among lanthanides and actinides, is especially noteworthy. 

---