2,4-Pentanedione, with sodium

Pentanedione, with sodium amide and diphenyliodonium chloride to give 1-phenyl-... 

The piif of 2,4-pentanedione is 9. Calculate the equilibrium constant for the acid-base reaction of 2,4-pentanedione with sodium ethoxide. The pA of ethanol is 15.9. 

The straightforward construction of substituted pyrone 4 proceeded as follows (see Scheme 6c). Alkylation of the monoanion of 2,4-pentanedione (8) with methyl iodide furnishes 3-methyl-2,4-pentanedione. Conversion of this substance into the corresponding dianion with sodium amide followed by selective carboxylation of the more basic site provides intermediate 7. Pyrone 4 is obtained after cyclization with l,l -carbonyldiimidazole and methylation of the resulting enol with dimethyl sulfate. 

Diphenyliodonium chloride, with 2,4-pentanedione and sodium amide to give 1-phenyl-2,4-pentanedione, 51,128... 

The preparation of highly functionalization selenophenes has been accomplished utilizing a three-component condensation reaction involving ketene dithioacetals, sodium selenide, and an activated carbonyl component (Scheme 13) <2003SL855, 2004S451, 2005PS939>. Ketene dithioacetal 122 was prepared from 2,4-pentanedione by condensation with carbon disulfide followed by methylation. Treatment of compound 122 with sodium selenide and ethyl bromoacetate gave selenophene 123 in modest yield. 

Two convenient methods of synthesis of the nickel(II) and cobalt-(II) complexes are described here. Method A, based on reaction of the sodium enolate salt of l,l,l,5,5,5-hexafluoro-2,4-pentanedione with the transition-metal chlorides in dimethylformamide (dmf), gives almost quantitative yields of Ni(hfa)2(dmf)2 and Co(hfa)2(dmf)2. Method B gives lower yields (50-75%) of the same products but can be carried out rapidly in common laboratory equipment (Method A is best carried out by vacuum-line techniques7). 

Acetylacetone (2,4-pentanedione) reacts with sodium hydroxide to give water and the sodium salt of a carbanion. Write a complete structural formula for the carbanion, and use resonance forms to show the stabilization of the carbanion. 

Draw the product formed when 2,4-pentanedione reacts with sodium hydride and then with pent-3-en-2-one. 

Silver fluoborate, reaction with ethyl bromide in ether, 46, 114 Silver nitrate, complexing with phenyl-acetylene, 46, 40 Silver oxide, 46, 83 Silver thiocyanate, 45, 71 Sodium amide, in alkylation of ethyl phenylacetate w ith (2-bromo-ethyl)benzene, 47, 72 in condensation of 2,4-pentanedione and 1 bromobutane to give 2,4-nonanedione, 47, 92 Sodium 2 ammobenzenesulfinate, from reduction of 2 mtrobenzenesul-finic acid, 47, 5... 

To a solution of 100 g. (1 mol) of 2,4-pentanedione and 40 g. (1 mol) of sodium hydroxide in 500 ml. of water is slowly added with stirring a solution of 144 g. (0.5 mol) of zinc sulfate heptahydrate in 500 ml. of water. After the suspension has stood for one hour, the white precipitate is filtered, washed with water, and dried, to give 122 g. (87%) of rather pure bis(2,4-pentanedionato)zinc hydrate with m.p. 138°. The crude product is dissolved in 11. of hot ethyl acetate, to which 50 ml. of 2,4-pentanedione has been added. The solution is filtered hot in order to remove a small amount of high-melting decomposition products. From the cooled solution, 90 g. (64%) of bis(2,4-pentanedionato) zinc hydrate is obtained as needles, m.p. 138 to 140°. 

Benzyl [15N]-3,4,5-trimethylpyrrol-2-carboxylate, 94, has been obtained77,79 in 38% yield in the reaction of [15N]-sodium nitrite with benzyl acetoacetate in AcOH at 10-5 °C, during 18 h, followed by addition of 3-methyl-2,4-pentanedione, AcONa, powdered zinc in AcOH, heating the suspension at 60 °C during 1 h, pouring the suspension over ice-water (5°C, 18 h) and recrystallization (Me0H-H20). 

In dim red light, the weighed hydrazide contained in one of the 500 ml flasks (ca. 67 g 95% of theory) is washed into a 1000 ml beaker with 263 ml IN hydrochloric acid. 239 ml distilled water, 239 ml ethanol (95%), and 37 ml 2,4-pentanedione are added, and the well-mixed solution left to stand in the dark at room temperature until the reaction is complete, i.e., about 30 minutes. The reaction mixture is neutralized with the addition of 263 ml 1 N sodium hydroxide, and the beaker covered with parafilm and refrigerated to ensure complete precipitation. The pyrazole is filtered at the pump, the mother liquor being returned to the beaker and used to wash out the last few crystals, washed with cold water, and sucked dry under a stream of dry nitrogen. The product is dried in vacuo over barium oxide or phosphorus pentoxide for at least twelve hours before proceeding to the next step, wherein anhydrous conditions will increase yield. Hofmann calls for drying the pyrazole in vacuo at 60°, which indicated the product to be fairly stable. So all the hydrazide is converted prior to aminization. 

Sodium, with l-bromo-3-chloro-cyclobutane to give bicyclo [l.l.O]butane, 51, 55 Sodium amalgam, 50, 50, 51 Sodium amide, with 2,4-pentane-dione and diphenyliodonium chloride to give l-phenyl-2, 4-pentanedione, 51, 128 Sodium azide, 50, 107 with mixed carboxylic-carbonic anhydrides, 51, 49 Sodium borohydride, reduction of erythro-3-methanesulfony-loxy-2-butyl cyclobutanecar-boxylate, 51, 12 reduction of 2-(1-phenylcyclo-pentyl)-4,4,6-trimethyl-5,6-dihydro-1,3(4H)-oxazine to 2-(1-phenylcyclopentyl)-4,4, 6-trimethyltetrahydro-l,3-oxazine, 51, 25 Sodium cyanoborohydride, used... 

Sodium amide, in alkylation, of di-phenylmethane, 48, 80 of ethyl phenylacetate with (2-bromoethyl)benzene, 47, 72 in condensation of 2,4-pentanedione and 1-bromobutane to give 2,4-nonanedione, 47, 92... 

The formation of a mixture of pyrylium salts when 2-acetylpyridine and chalcone reacted in perchloric acid was overcome by treating the reactants with ethanolic sodium hydroxide. The pentanedione was isolated and subsequently oxidized by reaction with chalcone and boron trifluoride (82JCS(P1)125). 

Beryllium has been determined [764] in non saline waters and in sea water at oceanic levels of 2.30pM. Two ml of 0.1M EDTA, 2ml of 1.0M sodium acetate, 1.0ml of benzene and lOOpl of l,l,l-trifluoro-2-4-pentanedione were added sequentially to 150ml samples. Following liquid-liquid extraction using detailed handling procedures, the organic phase was mixed with 1.0ml of 1.0M sodium hydroxide (de-emulsifier), washed several times with distilled water and the resultant beryllium l,l,l-trifluoro-2,4-pentanedione complex analysed by gas chromatography with electron capture detection. 

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