Enantioselective resolution of (R,S)-1-phenylethanol catalyzed by lipases immobilized in starch films

Abstract

Lipases de diferentes fontes e dois micélios, na forma livre ou imobilizados em filme de amido de gengibre, foram utilizados como catalisadores na reação do (R,S)-1-feniletanol (1) com acetato de vinila e outros agentes acilantes. Os efeitos de vários parâmetros na resolução de (1) catalisada pela lipase de Burkholderia cepacia (LBC) imobilizada em filme de amido de gengibre (tipo do doador acila, razão molar álcool:doador acila, temperatura e solvente orgânico) foram avaliados. A eficiência catalítica da LBC imobilizada em blendas de amido de gengibre e poli (oxido de etileno) (PEO), em diferentes composições, também foi estudada. Os acetato de vinila e o de iso-propenila forneceram as maiores conversões (9%) e excessos enantioméricos em (R)-éster (> 99%). A razão molar álcool:doador acila e temperatura ótima foram de 1:1 e 28 °C, respectivamente. A mistura de n-hexano/glicerol (9:1 v:v) foi a mais adequada para esta reação (conversão 23%, E > 200). A blenda de amido de gengibre/PEO (7:3 m/m) foi reutilizada por seis vezes consecutivas.Lipases from different sources and two mycelium-bound lipases, in a free or immobilized form, in ginger starch film were screened as biocatalysts in the reaction of (R,S)-1-phenylethanol (1) with vinyl acetate and other acylating agents. The effect of various reaction parameters in the resolution of (1) catalyzed by lipase from Burkholderia cepacia (BCL) immobilized in ginger starch film was evaluated (acyl donor type, alcohol:acyl donor molar ratio, temperature and organic solvent). The catalytic efficiency of BCL immobilized in polymeric blends of ginger starch and polyethylene oxide (PEO), in different compositions, was also studied. Vinyl acetate and iso-propenyl acetate furnished the highest conversion (9%) and enantiomeric excess (> 99%) of the (R)-ester. The alcohol:acyl donor molar ratio and temperature optimum were 1:1 and 28 °C, respectively. The mixture of n-hexane/glycerol (9:1 v:v) was the most adequate for this reaction (conversion 23%, E > 200). The ginger starch/PEO (7:3 m/m) blend was successfully reused six times consecutively. Keywords: starch film, immobilization, lipases, enzymatic resolution IntroductionIn recent years, the application of enzymes and microorganisms as biocatalysts in organic synthesis has become a well-known technique.1,2 Enzymatic procedures to obtain a wide range of products under mild and environmentaly-friendly conditions have become attractive and promising due to the excellent stereoselectivity of enzymes.3 Lipases (triacylglycerol hydrolases EC 3.1.1.3) are the most widely applied enzymes for regio-, chemoand enantioselective biotransformations, because they also possess wide substrate specificity, have an excellent ability to recognize chirality, and do not require cofactors.1,4 They have found wide usage in a growing range of industrial applications, such as in detergents, food processing, biotransformations, waste treatment and bioremediation. They have been used by the pharmaceutical, cosmetics, textile, leather and paper industri...

The Influence of Organic Medium and Supports in the Resolution of (R,S)-Menthol Catalyzed by Lipases

“…The choice of the solvent mixture composition and temperature were based in previous works. 19,24 In Figure 2, the results for the degrees of conversion and ee s are reported for the reactions conducted using the solvents pure or in mixtures with the different ILs, in which the product was detected. These exhibited ee p and E values of > 99% and > 200, respectively.…”

“…These films have been used in industry in many areas, such as in the production of food packaging bags from biodegradable wastes, and more recently for lipase immobilization. 15,18,19 Vol. 27, No.…”

Recent Advances in the Use of Glycerol as Green Solvent for Synthetic Organic Chemistry

“…Asymmetric reduction of the α-chloroacetophenone 40 in glycerol, with a cultured whole-cell biocatalyst of the yeast Williopsis californica, was also developed by Sugai and co-workers in their synthetic approach to (R)-terbutaline hydrochloride 41, a potent β 2 -adrenoceptor-stimulating agent (Scheme 35) [103]. In addition to these reduction processes, glycerol was shown to be an excellent alternative for use as a co-solvent in the resolution of racemic phenylethanol with different acylating reagents (vinyl acetate, ethyl acetate, iso-propenyl acetate or acetic anhydride) catalyzed by the Burkholderia cepacia lipase immobilized in ginger starch film [104]. The mixture hexane/glycerol was particularly adequate for such ends.…”

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