Pentan-2,4-dione

Champmartin D and Rubini P 1996 Determination of the 0-17 quadrupolar coupling constant and of the C-13 chemical shielding tensor anisotropy of the CO groups of pentane-2,4-dione and beta-diketonate complexes in solution. NMR relaxation study/norg. Chem. 35 179-83... 

Cyano-4,6-dlmethyl-2-pyrldone (7) Pentane 2 4 dione 5 (4 85 g 48 5 mmol), cyanoacetamide 6 (4 S g, S3 mmol) and piperidine (2 mL) in EtOH (SO mL) were heated to reflux for 45 mm The product crystallized on cooling Recrystallizatlon from ElOH gave 5 5 4 g of 7 (63 68%) mp298-300 C... 

Although nitrosation of (l-dicarbonyl compounds becomes increasingly more facile upon successive replacement of the a alkyl groups with perfluoroalkyl groups because of the increased ionization of the perfluorinated enolate (equation 7), the stability of the nitrosodiketone tautomers decreases Thus, 1,1,1-trifluoro pentane-2,4-dione and 1,1,1,5,5,5-hexafluoropentane 2,4 dione mtrosate much faster than penta-2,4 dione but yield ketoximes, which decompose upon workup... 

Pyrimido[5, 4 4,5]pyrazolo[3,2-c][l,2,4]triazine derivatives 1049and 1050 were prepared by treatment of diazo compound 1048, prepared from 1047, with pentane-2,4-dione and ethyl acetoacetate, respectively [92JCS(Pl)239]. 

This valuable method utilizes the O-TMS enol ethers derived from either pentane-2,4-dione or methyl acetoacetate, the former being the more reactive. Even t-alcohols are rapidly and quantitatively silylated in DMF at room temperature. A similar technique can be used to introduce the TBDMS group, although here ptsa catalysis is required (4). 

Paraformaldehyde. 122 Pentan-3-one, 134 Pentane-2,4 dione, 92.121 Peracetic acid, 61... 

Pentan-2,4-dion-bis-oxim wird an Blei/30%iger Schwefelsaure zu 3,5-Dimethyl-pyra-zolidin (40% d.Th.) cyclisiert4 ... 

In certain cases. X-ray crystallography has shown that a single H—A can form simultaneous hydrogen bonds with two B atoms bifurcated or three-center hydrogen bonds). An example is an adduct (1) formed from pentane-2,4-dione (in its... 

Allyl carbonate esters are also useful hydroxy-protecting groups and are introduced using allyl chloroformate. A number of Pd-based catalysts for allylic deprotection have been developed.209 They are based on a catalytic cycle in which Pd° reacts by oxidative addition and activates the allylic bond to nucleophilic substitution. Various nucleophiles are effective, including dimedone,210 pentane-2,4-dione,211 and amines.212... 

Zinc complex formation with 1,3-diketones in aqueous solution has been investigated with pentane-2,4-dione, l,l,l-trifluoropentane-2,4-dione, and 4,4,4-trifluoro-l-(2-thienyl)butane-l, 3-dione. The buffer dimethylarsinic acid was shown to have a catalytic effect on complex formation with pentane-2,4-dione and the proton transfer reactions were affected.471,472 High-resolution solid state 13C NMR studies of bis(2,4-pentanedionato) zinc complexes have been carried out.473... 

Bekiaris et al. have studied the reaction of fluorinated pentane-2,4-diones and phosphanes and have reported the formation of bicyclic compounds and phosphaadamantanes <1997CB1547>. Compounds 167 and 168 were formed in a diasteroselective manner (Scheme 13) and their structures were determined by single crystal X-ray structure analysis. 

Dimerization and condensation of pentane-2,4-dione by molybdenum(VI) oxide tetrachloride (MoOC14) affords l,3,5,7-tetramethyl-2,4,6,8-tetraoxa-adamantane, the structure of which is determined by elemental analysis, IR, mass, and PMR spectroscopy.188... 

Moffett [179] determined chromium in seawater by Zeeman corrected graphite tube atomisation atomic absorption spectrometry. The chromium is first complexed with a pentan-2,4 dione solution of ammonium 1 pyrrolidine carbodithioc acid, then this complex extracted from the water with a ketonic solvent such as methyl isobutyl ketone, 4-methylpentan-2-one or diisobutyl ketone. 

The AS value for pentane-2,4-dione in Table 3 is compatible with a double-minimum potential for the intramolecular hydrogen bond in the enol. This was also the conclusion reached from the microwave and photoelectron spectra. For unsymmetrically substituted diketones, for example 1,1,1-trifluoropentane-2,4-dione, measurement of 13C chemical shifts has been used to estimate values for the equilibrium constant K = [R]/[L] in (38)... 

Reduction of diketones such as pentane-2,4-dione using (RfBiNAP-RuCF under hydrogen (75 100 atm) gives the corresponding diol, in this case (R),(R)-2,4-pentanediol with an excellent diastereomer ratio (98 %) and optical purity (>99 %)[48]. 

The reaction of compound 376 with hydrazine gives product 377 that has been transformed into similar triazoles 378, after reaction with carbon disulfide in the presence of alcoholic potassium hydroxide, benzoic acid in the presence of phosphoms oxychloride, or 3-[bis-(methylthiomethylene)]pentan-2,4-dione and l,l-dicyano-2,2-dimethylthioethylene, in refluxing -butanol (Scheme 40) (Table 55) <2000FES641>. 

Yet another hetero-dien for cycloaddition reactions of glycals that had been used for the preparation of 2-deoxyglycosides is 2,4-dioxo-3-thioxo-pentane, generated in situ from 3-thiophthalimido-pentane-2,4-dion. The cycloaddition occurs with high... 

Pentane-2, 4-dione, acetylacetone CH3CO CH2 COCH3-a(3-diketone ... 

Direct coupling of carbon nucleophiles with 1,3-dinitrobenzene is promoted by ultraviolet irradiation in the presence of quaternary ammonium fluorides, which can act not only as the base to generate the carbon nucleophile, but also as a proton transfer agent in the rearomatization step [83], The dinitrobenzene acts as the electron acceptor in the photochemical step. No reaction occurs in the absence of the fluoride and, surprisingly, although simple ketones, nitriles, esters and fl-kcto esters react, pentan-2,4-dione does not. 

Glycopyranosyl halides react with ethyl acetoacetate and pentan-2,4-dione under soliddiquid phase-transfer catalytic conditions, using potassium phosphate as the base, providing the C-alkylated derivatives (40-60%) ]94],... 

---