Enzymatic reactions in organic synthesis: 2- ester interchange of vinyl esters

Degueil-Castaing, Marie; Jeso, B. De; Drouillard, S.; Maillard, B.

doi:10.1016/s0040-4039(00)95884-2

Cited by 216 publications

(37 citation statements)

References 5 publications

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“…The initial acylation rate in 2-methoxyethyl acetate was, as expected, lower than in ethyl acetate, since the methoxy group delocalizes the charge and thus 2-methoxy ethyl acetate releases an acyl group more slowly than ethyl acetate. An irreversible acylation occurred in the case of isopropenyl acetate and vinyl acetate [20,21] (Fig. 3).…”

Section: Effect Of Acyl Donormentioning

confidence: 98%

Kinetics and modeling of (R,S)‐1‐phenylethanol acylation over lipase

Кирилин

Sahin

Mäki‐Arvela

et al. 2010

Int J of Chemical Kinetics

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The kinetics of the acylation of (R,S)-1-phenylethanol was investigated using lipase as a catalyst. The main parameters were temperature, reaction atmosphere, different acyl donors, and different amounts of acyl donor as well as the presence of some additives in the reaction mixture. The initial reaction rate increased with increasing temperature and with a decreasing amount of an acyl donor. The activated esters, such as isopropenyl-and vinyl acetate, exhibited very high acylation rates for R-1-phenylethanol, whereas low rates were obtained with ethyl acetate and 2-methoxyethyl acetate. The addition of water and acetophenone decreased the acylation rate. A kinetic model was developed based on a sequential step mechanism, in which enzyme was reacting in the first step with an acyl donor followed by the reaction of a modified enzyme complex with the reactant, R-1-phenylethanol. Comparison with experimental data obtained at different temperatures allowed simplification of this model, leading to a kinetic equation with just one apparent parameter. The influence of the amount of acyl donor, ethyl acetate, could be quantitatively described by taking into account the competitive inhibition of the ethanol produced. The rate constants and apparent activation energy for experiments performed under different temperatures and the amounts of acylation agent were determined. The apparent activation energy was 24.5 kJ/mol. C

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Section: Effect Of Acyl Donormentioning

confidence: 98%

Kinetics and modeling of (R,S)‐1‐phenylethanol acylation over lipase

Кирилин

Sahin

Mäki‐Arvela

et al. 2010

Int J of Chemical Kinetics

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“…Activated vinyl esters were selected as the acyl donor because of the irreversible nature of the reaction and absence of low-volatility side-products that would hamper the work-up procedure (Degueil-Castaing et al, 1987;Wang and Wong, 1988). Anhydrous organic solvents were needed so that the transesteri®-cation reaction could be catalyzed without hydrolysis of the vinyl acrylate or the resulting MGA product.…”

Section: Synthesis Of A-methyl Glucoside Acrylatementioning

confidence: 99%

Scale‐up of pseudo solid‐phase enzymatic synthesis of α‐methyl glucoside acrylate

Rethwisch²

2002

Biotech & Bioengineering

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The successful scale-up of the enzymatic synthesis of alpha-methyl glucoside acrylate from laboratory-scale (milliliter) to pilot-scale (liter) was examined. Specifically, Candida antarctica lipase B (Novozym 435) was used as a biocatalyst to produce alpha-methyl glucoside acrylate via the transesterification of alpha-methyl glucoside (MG) with vinyl acrylate (VA) using acetone as a solvent. This is a pseudo-solid-phase synthesis; only a fraction of the alpha-methyl glucoside and the product are soluble in acetone. Molecular sieves were used to remove traces of water in the reaction medium and to increase enzyme stability by removing the acetaldehyde by-product. A general method was also developed to purify and recover the monoacrylate product from unreacted sugar and undesired diester by a simple crystallization and precipitation process.

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“…Additional experimental evidence for the formation of an acyl-enzyme intermediate has been given recently (Kawase, Sonomoto and Tanaka, 1992). If vinyl acetate is used as the acyl donor, the reaction becomes virtually irreversible because the resulting vinylalcohol tautomerizes completely to acetaldehyde (Degueil-Castaing et al, 1987). In the case of optical resolutions of racemic mixtures by transesterification the two enantiomers have to be considered as substrates competing for the same site on the enzyme.…”

Section: Kinetic Modelmentioning

confidence: 99%

Kinetic Analysis and Simulation Studies for Lipase-Catalysed Resolution of Racemic 2-Methyl-1-Pentanol

et al. 1993

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The lipase-catalysed optical resolution of a racemic mixture of 2-methyl-1-pentanol by transesterification using vinyl acetate as acyl donor has been studied experimentally. A mechanistic model has been developed for the double-substrate reaction sequence treating both enantiomers as competing substrates. The model is based upon a ping-pong mechanism with alternative substrates involving an acyl-enzyme intermediate. The kinetic constants of the model have been evaluated using initial rate experiments and nonlinear regression analysis. The model successfully predicts the evolution of the enantiomeric excess of substrate (eeR) and the degree of conversion with time for batch experiments with various initial concentrations of vinyl acetate and (R,S)-2-methyl-l-pentanol. Furthermore, the rate equations have been used to theoretically study the dynamic progression of a continuous enzyme-catalysed resolution process. The enantiomeric excess as a function of conversion for different process configurations is discussed. It is found, that the maximum attainable eeR is strongly dependent on the residence time distribution of the continuous reactor and is rather low for a continuous stirred tank reactor (CSTR) due to competitive inhibition effects.KEY WORDS Enzyme kinetics, mathematical modelling, optical resolution, lipase, 2-methyl-lpentanol. LIST OF SYMBOLS

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Enzymatic reactions in organic synthesis: 2- ester interchange of vinyl esters

Cited by 216 publications

References 5 publications

Kinetics and modeling of (R,S)‐1‐phenylethanol acylation over lipase

Kinetics and modeling of (R,S)‐1‐phenylethanol acylation over lipase

Scale‐up of pseudo solid‐phase enzymatic synthesis of α‐methyl glucoside acrylate

Kinetic Analysis and Simulation Studies for Lipase-Catalysed Resolution of Racemic 2-Methyl-1-Pentanol

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