Ildikó Kmecz

Kinetic resolution of 1-(benzofuran-2-yl)ethanols by lipase-catalyzed enantiomer selective reactions

Abstract Kinetic resolution of racemic 1-(benzofuran-2-yl)ethanols rac - 1a – d was performed by lipase-catalyzed enantiomer selective acylation ( E ≫100) yielding (1 R )-1-acetoxy-1-(benzofuran-2-yl)ethanes ( R )- 2a – d and (1 S )-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 CO 2 medium. Racemization-free lipase-catalyzed ethanolysis of the (1 R )-1-acetoxy-1-(benzofuran-2-yl)ethanes ( R )- 2a – d yielded almost quantitatively the enantiopure (1 R )-1-(benzofuran-2-yl)ethanols ( R )- 1a – d .

Effect of achiral support on the resolution of tetramisole by supercritical fluid extraction

Abstract The enantiomers of tetramisole were produced by partial diastereomeric salt formation with O , O ′-dibenzoyl-(2 R ,3 R )-tartaric acid monohydrate and subsequent supercritical fluid extraction (SFE) of the unreacted enantiomers in the presence of an achiral support. The effect of the activated carbon and Perfil 100™ on the efficiency of chiral separation were studied. The kinetics of the process was found to be an important factor affecting enantioselectivity. When the parameters were properly set, much better resolution efficiency ( F ) and higher enantiomeric purity were achieved than in the equilibrium. The presence of Perfil 100™ and activated carbon caused an increase as high as 53 and 84% in F , respectively, compared to that achieved without using any supporting material. Thus during the development of a resolution procedure, beside the proper resolution agent, optimised molar ratio and other parameters, the selection of achiral addict(s) may be also an important point.

Neat lipase-catalysed kinetic resolution of racemic 1-phenylethanol and a straightforward modelling of the reaction

Abstract Enzymatic kinetic resolution of racemic 1-phenylethanol catalysed by immobilized Candida antarctica lipase B was investigated in a neat system at the temperature range of 30–70 °C. Synthetic triglycerides, namely glycerol triacetate and glycerol tributyrate, were applied as the esterification agents. Both esterification agents were efficient regarding to the enantioselectivity (>1000). Initial rate of reaction and the kinetic constants were influenced by the applied esterification agent significantly. A detailed modelling approach is presented and verified in the temperature range on 30–60 °C for the tributyrin system.