Lithium acetylacetonate

The cooling bath is removed, and the mixture is left to reach room temperature with an air bath and stirred for 30 min. The solvent is removed under vacuum to afford a brown solid and then 30 mL of petroleum ether (40-60°C), freshly distilled from Na/benzophenone under nitrogen, is added to the flask. The dark yellow suspension is filtered to remove the lithium acetylacetonate, and the solid is washed twice with 7 mL of petroleum ether. The solvent is removed from the filtrate under vacuum to yield a dark yellow solid (1.95 g), which is sublimed at 50-60°C (10 3torr). The product is a yellow crystalline solid. Yield 1.84 g (86%). ... 

The particular case of lithium acetylacetonate (acac), a canonic example of /I-diketone enolate, was also examined early. It was shown that its chelated (Z,Z) conformation was almost exclusive in methanol at — 60 °C and that dimers were probably formed in which one of the two lithium cations would be chelated by the two acac anions272. A somewhat similar dimer, obtained from the lithium enolate of ethyl acetoacetate complexed by a 2.1.1 cryptate, was characterized in one of the first 7Li NMR studies of enolates (Scheme 65)273. Note that the structure of the three ft -diketone mono- and dilithium enolates displayed in Scheme 64 has been studied, despite their poor solubility, in both THF-dg and DMSO-d6 by 13C NMR260. The data obtained for the monoenolates are consistent with rapidly equilibrating dimers, while the dimers of dienolates seem to form slowly on the NMR time scale. 

SCHEME 65. NMR spectrum of lithium acetylacetonate ( II, 60 MHz, top) and of ethyl acetoac-etate lithium enolate (7Li with LiC104 in water as external reference, 35 MHz, bottom) 2.1.1 cryptate = 4,7,13,18-tetraoxa-l J0-diazabicyclo[8.5.5]eicosane272,273... 

What do the differences in properties between lithium acetylacetonate (m.p. very high, insoluble in chloroform) and beryllium acetylacetonate (m.p. 108 , b.p. 270°, soluble in chloroform) suggest about their structures ... 

Solution From their melting and solubility properties, the structures of lithium acetylacetonate and berylliimi acetylacetonate are, respectively, ionic or salt-like and non-ionic or covalent. 

Since the melting point of lithium acetylacetonate is very high, and beryllium acetylacetonate relatively low,one expects the former to be ionic with the latter being nonionic. ... 

Other reagents that have been used to reduce support-bound aromatic nitro compounds include phenylhydrazine at high temperatures (Entry 5, Table 10.12), sodium borohydride in the presence of copper(II) acetylacetonate [100], chromium(II) chloride [196], Mn(0)/TMSCl/CrCl2 [197], lithium aluminum hydride (Entry 3, Table... 

A 100-mL, two-necked, round-bottomed flask with a stirring bar, a nitrogen inlet, and a rubber septum is evacuated and filled with nitrogen three times. Iron(II) bis(acetylacetonate) (2.01 g, 7.9 mmol) is added to the flask in a nitrogen bag. Then 20 mL of anhydrous THF, freshly distilled from Na/benzo-phenone under nitrogen, is added to the flask, the stirring is started, and the dark yellowish-brown solution is cooled to — 78°C with a dry ice/ acetone bath. A suspension of pentamethylcyclopentadienyl lithium (1.125 g, 7.9 mmol) in 20 mL of anhydrous THF is added to the reaction flask via syringe. The purity and the stoichiometric amount of pentamethylcyclopentadienyl lithium are crucial to avoid side reactions. 

N, N-Bis(2-oxo-3-oxazolidinyl)-phosphoramidic chloride, 39 Hexamethyldisilazane, 141 Thionyl chloride, 297 Zirconium(IV) acetylacetonate, 351 of aromatic rings Lithium o-lithiophenoxide, 166 of compounds containing active hydrogens... 

Nickel(II) acetylacetonate, 221 Nickel boride, 197 Nickel carbonyl, 198 Nickel chloride-Lithium, 197 Raney nickel, 197, 265 Raney nickel-2-Propanol, 266 Sodium borohydride-Nickel boride, 280... 

The phase-stabilized AN is prepd by mixing 90 parts AN, 10 ps K nitrate some water, heating the mixt to 140°F, drying and grinding to 40 micron size particles. The proplnt is compressed into grains. Example of compn AN 82.95, K nitrate 9.22, petroleum pitch 4.11 90/10 copolymer of l,3-butadiene/2-methyl-5 -vinyl pyridine 1.76 Amm dichromate 1.96%] EE)R.MacDonald A.M.Bedard, "Methods of Chemical Analysis of Cardeplex Propellant No 4760/A5 and Its Ingredients", CARDE TR426/63 (1963) (Cardeplex No 4760/A5 is a composite ammonium perchlorate-polyurethane proplnt. Analysis of fully cured product includes detns of Amm perchlorate, Al, ferric acetylacetonate, phenyl-/3 -naphthylamine, lithium fluoride total iron) FF)Anon,... 

A solution of copper(II)acetylacetonate (5 mg), 4-chloro-benxaldehyde and tosyl hydrazone lithium salt (2.5 eq) were mixed and heated to 45 °C 3 hours, cooled, and 1ml EtOAc/water, 1 1, added. The epoxide was isolated as a white solid in 54% yield with a trans/cis ratio of 2.8 1, respectively. 

LiCH[C(0)CHj]2 (lithium 2,4-pentanedionate) [structure consists of endless strings of pseudo Li(acac)2 groups (acac = acetylacetonate), connected by bridging lithium atoms there are two different types of lithium geometry tetrahedral and tetragonal. 

CPB1525). The 5-formyluracil is converted into quinazolines by condensation with acetylacetone (81JOC3949) or by cycloaddition of the lithium dienolate to olefins (80TL531). Aldehyde dienophiles lead to pyrano[4,3-rfipyrimidines 181 H( 15)289]. (Scheme 95),... 

---