- METHOD FOR EXTRACTING ASYMMETRIC B-DIKETONE COMPOUND FROM B-DIKETONE COMPOUND
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The present invention provides a method of extracting an asymmetric β-diketone compound from a β-diketone compound containing at least one symmetric β-diketone compound mixed in the asymmetric β-diketone compound, and the method includes the step (A) of adjusting a pH of a mixed solution of the β-diketone compound and water at 11.5 or more and dissolving the β-diketone compound into water to form a β-diketone compound solution and the step (B) of subsequently adjusting the pH of the β-diketone compound solution at 9.5 or less and recovering the asymmetric β-diketone compound of Chemical Formula 1 separated from the β-diketone compound solution. The present invention further includes at least either (a) a step of setting the upper limit of the pH of the mixed solution to 12.5 to form a β-diketone compound solution in the step (A) and bringing the β-diketone compound solution into contact with a hydrophobic solvent or (b) a step of setting the lower limit of the pH of the β-diketone compound solution to 8.0 in the step (B).
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Paragraph 0074-0076
(2015/11/16)
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- Promiscuous substrate binding explains the enzymatic stereoand regiocontrolled synthesis of enantiopure hydroxy ketones and diols
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Regio- and stereoselective reductions of several diketones to afford enantiopure hydroxy ketones or diols were accomplished using isolated alcohol dehydrogenases (ADHs). Results could be rationalised taking into account different (promiscuous) substrate-binding modes in the active site of the enzyme. Furthermore, interesting natural cyclic diketones were also reduced with high regio- and stereoselectivity. Some of the 1,2 and 1,3-diketones used in this study were reduced by employing a low excess of the hydrogen donor (2-propanol) due to the quasi-irreversibility of these ADH-catalysed processes. Thus, using lower quantities of co-substrate, scale-up could be easily achieved.
- Kurina-Sanz, Marcela,Bisogno, Fabricio R.,Lavandera, Ivan,Orden, Alejandro A.,Gotor, Vicente
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supporting information; experimental part
p. 1842 - 1848
(2011/02/25)
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- Porphyrins with exocyclic rings. Part 22: Synthesis of deoxophylloerythroetioporphyrin (DPEP), three ring homologues, and five related nonpolar bacteriopetroporphyrins using a western ring closure and an improved b-bilene methodology
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Dipyrrolic intermediates incorporating five-membered carbocyclic rings are easily prepared from cyclopenta[b]pyrroles, and this unit represents the southern half of the DPEP-type geoporphyrins found in organic-rich sediments such as oil shales and petroleum. Related dipyrroles with six-, seven- or eight-membered carbocyclic rings were shown to give b-bilenes when reacted with dipyrrylmethane carbaldehydes under mildly acidic conditions. Following deprotection of the terminal ester groups, cyclization with TFA-CH(OMe)3 gave a series of ring homologues of deoxophylloerythroetioporphyrin (DPEP). The b-bilenes generated from the five-membered ring dipyrroles proved to be rather unstable and had to be used directly without purification. Cyclization gave DPEP contaminated with an etioporphyrin by-product, but these could be separated as the nickel(II) derivatives by flash chromatography. This approach gave superior yields of DPEP compared to previously reported methods. In addition, the methodology could be extended to the synthesis of related petroporphyrins, and a series of five molecular fossils derived from bacteriochlorophylls d were synthesized by this approach.
- Lash, Timothy D.,Li, Wei,Quizon-Colquitt, Desiree M.
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p. 12324 - 12342
(2008/03/13)
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- kINETICS AND MECHANISM OF THE REACTION OF IRON(III) WITH 6-METHYL-2,4-HEPTANEDIONE AND 3,5-HEPTANEDIONE
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The kinetics of the reactions of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione to form the corresponding monocomplexes have been studied spectrophotometrically in the range 5 deg C to 16 deg C at Ι 25 mol 1-1 in aqueous solution.In the proposed mechanism for the two complexes, the enol form reacts with the metal ion by parallel acid-independent and inverse-acid paths.The kinetic constants for both pathaways have been calculated at five temperatures.Activation parameters have also been calculated.The results are consistent with an associative activation for Fe(H2O)63+ and dissociative activation for Fe(H2O)5(OH)2+.The differences in the results for the complexes of heptanediones studied are interpreted in terms of steric factors.
- Hernando, Jose M.,Montero, Olimpio,Blanco, Carlos
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p. 1984 - 1990
(2007/10/02)
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