600727-08-0Relevant articles and documents
Tailored sol-gel immobilized lipase preparates for the enzymatic kinetic resolution of heteroaromatic alcohols in batch and continuous flow systems
Moisǎ, Mǎdǎlina Elena,Spelmezan, Cristina Georgiana,Paul, Cristina,Bartha-Vári, Judith Hajnal,Bencze, László Csaba,Irimie, Florin Dan,Paizs, Csaba,Péter, Fráncisc,To?a, Monica Ioana
, p. 52977 - 52987 (2017)
Tailored immobilized lipases from Candida antarctica B and Pseudomonas fluorescens, with improved thermal and operational stability, were prepared through fine tuning of the structure of the sol-gel matrix, using various binary or ternary precursor mixtures for the EKR of various chiral heteroaromatic secondary alcohols with benzofuran, benzo[b]thiophen, phenothiazine and 2-phenylthiazol moieties. The operational stability in batch process was studied for five selected systems by performing reuse experiments, using the conversion, enantiomeric excesses and enantiomeric ratio as parameters, demonstrating the dependence of the sol-gel lipase preparate performance on the structure of both biocatalyst and substrate. The resolution of the benzofuranic substrates with the best performing biocatalysts was studied in continuous-flow mode, using the productivity as a criterion. The specific reaction rates under continuous-flow operation (rflow) were higher than those obtained in batch mode (rbatch) in both cases, sustaining its usefulness for further process development.
Combined ruthenium(II) and lipase catalysis for efficient dynamic kinetic resolution of secondary alcohols. Insight into the racemization mechanism
Martin-Matute, Belen,Edin, Michaela,Bogar, Krisztian,Kaynak, F. Betuel,Baeckvall, Jan-E.
, p. 8817 - 8825 (2007/10/03)
Pentaphenylcyclopentadienyl ruthenium complexes (3) are excellent catalysts for the racemization of secondary alcohols at ambient temperature. The combination of this process with enzymatic resolution of the alcohols results in a highly efficient synthesis of enantiomerically pure acetates at room temperature with short reaction times for most substrates. This new reaction was applied to a wide range of functionalized alcohols including heteroaromatic alcohols, and for many of the latter, enantiopure acetates were efficiently prepared for the first time via dynamic kinetic resolution (DKR). Different substituted cyclopentadienyl ruthenium complexes were prepared and studied as catalysts for racemization of alcohols. Pentaaryl-substituted cyclopentadienyl complexes were found to be highly efficient catalysts for the racemization. Substitution of one of the aryl groups by an alkyl group considerably slows down the racemization process. A study of the racemization of (S)-1-phenylethanol catalyzed by ruthenium hydride η5-Ph5CpRu(CO) 2H (8) indicates that the racemization takes place within the coordination sphere of the ruthenium catalyst. This conclusion was supported by the lack of ketone exchange in the racemization of (S)-1-phenylethanol performed in the presence of p-tolyl methyl ketone (1 equiv), which gave 1% of 1-(p-tolyl)ethanol. The structures of ruthenium chloride and iodide complexes 3a and 3c and of ruthenium hydride complex 8 were confirmed by X-ray analysis.
Kinetic resolution of 1-(benzofuran-2-yl)ethanols by lipase-catalyzed enantiomer selective reactions
Paizs, Csaba,Tosa, Monica,Bodai, Viktoria,Szakacs, Gyoergy,Kmecz, Ildiko,Simandi, Bela,Majdik, Cornelia,Novak, Lajos,Irimie, Florin-Dan,Poppe, Laszlo
, p. 1943 - 1949 (2007/10/03)
Kinetic resolution of racemic 1-(benzofuran-2-yl)ethanols rac-1a-d was performed by lipase-catalyzed enantiomer selective acylation (E?100) yielding (1R)-1-acetoxy-1-(benzofuran-2-yl)ethanes (R)-2a-d and (1S)-1-(benzofuran-2-yl)ethanols (S)-1a-d in highly enantiopure form. The degree of enantiomer selectivity for enzymatic alcoholysis/hydrolysis processes starting from racemic 1-acetoxy-1-(benzofuran-2-yl)ethane rac-2 was also tested under various conditions including supercritical CO2 medium. Racemization-free lipase-catalyzed ethanolysis of the (1R)-1-acetoxy-1-(benzofuran-2-yl)ethanes (R)-2a-d yielded almost quantitatively the enantiopure (1R)-1-(benzofuran-2-yl)ethanols (R)-1a-d.
