- Urea/transition-metal cooperative catalyst for anti-selective asymmetric nitroaldol reactions
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A cooperative catalyst that features urea H-bonding and a cobalt center was developed for anti-selective asymmetric Henry reactions (see scheme). The H-bonds of urea play a crucial role in the improvement in yield (from 30 % to 84 %), enantioselectivity (
- Lang, Kai,Park, Jongwoo,Hong, Sukwon
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p. 1620 - 1624
(2012/04/05)
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- MAO inhibition by arylisopropylamines: The effect of oxygen substituents at the β-position
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Twenty-nine arylisopropylamines, substituted at the β-position of their side chain by an oxo, hydroxy, or methoxy group, were evaluated in vitro as MAO-A and MAO-B inhibitors. The oxo derivatives ('cathinones') were in general less active as MAO-A inhibitors than the corresponding arylisopropylamines, but exhibited an interesting MAO-B inhibiting activity, which was absent in the hydroxy, methoxy, and β-unsubstituted analogues. These results suggest that selective affinity for the two MAO isoforms in this family of compounds is modulated not only by the aryl substitution pattern but also by the side-chain substituents on the arylalkylamine scaffold.
- Osorio-Olivares, Mauricio,Rezende, Marcos Caroli,Sepulveda-Boza, Silvia,Cassels, Bruce K.,Fierro, Angelica
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p. 4055 - 4066
(2007/10/03)
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- Chiral separation of drug enantiomers by capillary electrophoresis using succinyl-β-cyclodextrin
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A capillary electrophoretic method for the enantiomeric separation of 11 drugs was developed using an uncoated fused-silica capillary and succinyl β-cyclodextrin as a chiral additive. The effect of the pH of the background electrolyte on selectivity and resolution was studied in the range pH 3.3-9.3. Best results were obtained in a neutral medium. Generally, the presence of a hydroxy group at the chiral C-atom of the analyte seems to be essential because similar compounds without a hydroxy group at the chiral centre did not show chiral resolution. In addition to the enantioselective inclusion into the chiral cavity, hydrogen bondings and formation of ion pairs between the negatively charged selector and cationic analytes can be assumed as mechanisms.
- Schmid,Wirnsberger,Guebitz
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p. 852 - 854
(2007/10/03)
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