Acetylacetone 2,4-pentanedione

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.). 

The scope of the condensation reaction has been extended considerably by varying the dicarbonyl compound employed. Diethyl 3-oxoglutarate, acetylacetone (2,4-pentanedione), and other compounds with structures analogous to that of ethyl acetoacetate, form compounds of constitution similar to that of II. 

An alternate method of proceeding from the hydrazide follows (U.S. Patent 3,085,092). To a solution of 1.4 g (1) in 5.5 ml 1 N HCI, 5 ml water, 5 ml EtOH, add 1 g acetylacetone (2,4 pentanedione), let stand 1 hour at room temperature and neutralize with 5.5 ml 1 N NaOH. Filter off the lysergyl pyrazole (II) and wash with water. Can purify by drying in vacuum at 60° C and recrystallizing from chloroform by the addition of ether. Heat 0.4 g (11) and 2.5 ml DEA at 100° C for 2 hours (or let stand 15 hours at room temperature, evaporate to dryness and heat a few minutes at 100° C in vacuum). Can recrystallize from CHCI3, petroleum ether or as described elsew here here. 

Figure 1 Transfer chemical potentials for selected iron complexes from water into aqueous methanol (on the molar scale, at 298 K). Ligand abbreviations not appearing in the list at the end of this chapter are acac = acetylacetonate (2,4-pentanedionate) dmpp = l,2-dimethyl-3-hydroxy-4-pyridinonate, the anion from (24) malt = maltolate (2-methyl-3-hydroxy-4-pyranonate, the anion from (233)).

The tris and bis complexes of acetylacetone (2,4-pentanedione) (167) with chromium(III) have been known for many years (168,169).739 The tris compound is generally prepared by the reaction of an aqueous suspension of anhydrous chromium(III) chloride with acetylacetone, in the presence of urea.740 Recently a novel, efficient synthesis of tris(acetylacetonato)chromium-(III) from Cr03 in acetylacetone has been reported.741 The crystal structure of the tris complex has been determined.744 A large anisotropic motion was observed for one of the chelate rings, attributed to thermal motion, rather than a slight disorder in the molecular packing. 

Finally, chelating ligands such as acctylacctonc enjoy resonance stabilization as a result of forming six-membered rings having some aromatic character. Acetylacetone (2.4-pentanedione) coordinates as an anionic enolate ligand ... 

The archetype of -diketones is acetylacetone (2,4-pentanedione Scheme 21 R = R = Me R" = H). Nickel complexes with this ligand are very numerous and are the ones studied in most detail. 

The checker reports the following procedure 2.3 g. NaOH as a 40% w/v aqueous solution was added to 5.74 g. acetylacetone (2,4-pentanedione) with stirring. The resultant white, virtually solid, mass was cooled and added to the ruthenium trichloride. 

Twenty-two grams (0.08 mol) of carbonatobis (ethylene-diamine) cobalt(III) chloride is treated with 80 ml. of 2 Af hydrochloric acid. When the reaction is complete, 16 ml. of acetylacetone (2,4-pentanedione) (0.16 mol) dissolved in 120 ml. of 1 M sodium hydroxide is added. The mixture is... 

Problem 31.26 Account for the formation of 2,4-dimethyIquinoline from aniline and acetylacetone (2,4-pentanedione) by the Doebner-von Miller synthesis. 

Acetylacetone reagent 7.5 ml acetylacetone (2,4-pentanedione) is added to 25 ml of isopropanol and mixed then 1 liter of 2 ilf ammonium acetate (pH 6.0) is added and mixed well prepare fresh daily... 

The syntheses of acetylacetone (2,4-pentanedione) derivatives of beryllium,18 aluminum,23 zirconium,14 and thorium6 are representative of this general method. 

Vanadium(IV) oxy(acetylacetonate) has been prepared by direct reaction of acetylacetone (2,4-pentanedione) with either hydrous vanadium(IV) oxide or an aqueous solution of an oxovanadium(IV) salt.1-3 Procedure A is an adaptation of this approach. The facts that acetylacetone can reduce vanadium(V) oxide to vanadium(IV) oxide, react as an acid4,5 with the latter to give the desired product, and behave as a solvent for that product are combined in procedure B to give a synthesis based directly upon readily available starting materials. 

CH3COCH2COCH3 Acetylacetone (2,4-pentanedione), 2 10 CH3C02C,H7 Isopropyl acetate, 3 48... 

Tautomerism is a combination of hydrogen-bonding and slow inter-or intra-molecular proton transfer. Jarrett et al. (1953) reported proton resonance spectra of acetylacetone (2,4-pentanedione) and 3-methyl-2,4-pentanedione. The spectra were found to be a superposition of... 

Acinetohacter johnsonii is able to degrade acetylacetone (2,4-pentanedione), utilizing a novel dioxygenase enzyme, as shown in Figure 40. The purified enzyme is dependent upon Fe for activity, implying that it is a nonheme iron-dependent dioxygenase. labeling studies and structure—activity relationships have been carried out... 

Compounds containing active methylene groups can be alkylated by alcohols with loss of hydrogen from that position. For example, in the presence of boron trifluoride, isopropyl alcohol and ethyl acetoacetate give ethyl 2-iso-propylacetoacetate in 60-70% yield 643 the isopropyl group can be introduced in the same way into acetylacetone (2,4-pentanedione) 644 and reactions of xanthhydrol with malonic esters have also been recorded in the literature.645... 

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