Enzymes in organic synthesis. 35. Stereoselective pig liver esterase catalyzed hydrolyses of 3-substituted glutarate diesters. Optimization of enantiomeric excess via reaction conditions control

Lam, Lister K. P.; Hui, R.; Jones, J. Bryan

doi:10.1021/jo00361a021

Cited by 163 publications

(19 citation statements)

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“…In enzymecatalysed reactions, increasing temperature generally decreases selectivity. [52][53][54][55][56][57][58][59][60][61][62] In a few studies, however, enhanced selectivity with increasing temperature, 63,64 or a maximum of enantioselectivity at a certain temperature, 38,65 or even indifference to temperature was found. 66 In most of the quoted examples, the enzyme-catalysed reactions were carried out in batch mode (in stirred or shaken flasks) and only a few studies on the temperature effects on lipase-catalysed KRs were performed in continuous-flow mode so far.…”

Section: Introductionmentioning

confidence: 99%

Lipase-Catalyzed Kinetic Resolution of 1-(2-Hydroxycyclohexyl)Indoles in Batch and Continuous-Flow Systems

et al. 2014

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The lipase catalysed kinetic resolution of three trans-1-(2-hydroxycyclohexyl)-indoles in both batch and continuous-flow systems is reported. Ring opening of cyclohexene oxide by the corresponding indole followed by enzymatic acylation with vinyl acetate resulted in novel, highly enantioenriched indole-substituted cyclohexanols and cyclohexyl acetates. The effect of the temperature on enantiomeric ratio (E) and productivity (specific reaction rate, r flow ) in the continuous-flow mode acylation was studied at analytical scale in the 0-70°C range.Preparative scale kinetic resolution of the three indole derivatives was performed in mixed continuous-and recirculation-flow mode resulting in almost complete conversion and good to excellent enantiomeric purity of the products.

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Section: Introductionmentioning

confidence: 99%

Lipase-Catalyzed Kinetic Resolution of 1-(2-Hydroxycyclohexyl)Indoles in Batch and Continuous-Flow Systems

et al. 2014

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“…Ce resultat est bien en accord avec le mecanisme d'action suppose des esterases et des lipases (14). L'acide initial n'est pas assez nucleophile pour attaquer l'acylenzyme intermediaire.…”

Section: Dansunclassified

Réactions enzymatiques en chimie organique: 5 ‐ estérifications compétitives

Drouillard

Degueil-Castaing

Jeso

et al. 1988

Bulletin des Soc Chimique

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Dansdes notes anterieures ( l ) , nous avons decrit nos premiers resultats sur une approche de l'hydrolyse enzymatique de diesters par l'btude de la selectivite dans le cas de competitions intermolbculaires sur la base d'une etude bibliographique. un autre acces specifique potentiel A des monoesters de diacides ou de diols nous a paru etre la monoestbrification catalysee par une enzyme du composb difonctionnel. Deux methodes de syntheses sont envisageables. D'abord une reaction directe entre un acide et un alcool (2-81 qui est parfois difficile A realiser, dans la mesure oh le pH de l'eau rbsiduelle entourant l'enzyme diminue fortement par suite de la presence de l'acide ( 9 ) . Une transestbrification peut pallier cet inconvenient et les taux de conversion peuvent Btre tres bleves (9-11). L'ensemble des travaux citbs a port6 essentiellement sur l'etude de la sterboselectivite des reactions. Seul KLIBANOV a mentionne que la Lipase Pancrbatique Porcine (LPP) (EC 3.1.1.3) presentait une bonne rbgiosblectivite, puisqu'elle permet d'effectuer l'estbrification du butanediol-1.3 en position 1 ou de sucres en position 2 ou 3 (12). Nous avons donc decide d'aborder le cas de la monoestbrification de diacides ou de diols en prenant. dans un premier temps, comme modQle l'etude de compbtitions intermolbculaires dont l'analyse est plus facile, l'objectif de ce travail etant d'obtenir une methode complementaire de l'hydrolyse enzymatique de diesters. En effet, compte-tenu de la sklectivitb des rbactions enzymatiques, il paralt raisonnable de penser que l'estbrification donnera le monoester qui ne peut Btre obtenu par hydrolyse. par exemple : Hz 0 X I Y -

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“…Concerning the latter. many studies (Jones and Mehes, 1979;Lam et a/., 1986;Bjorkling et a/.. 1987;Lee et al, 1995;Hansen er al., 1995;Wolff et al, 1997) have explored addition of water-miscible organic cosolvents to alter enzymatic enantioselectivity. Surprisingly, no work has focussed on the effect of another obvious additive, inorganic salts, on enantioselectivity of enzymes (Faber et 01.. 1993).…”

Section: Introductionmentioning

confidence: 99%

Computational and Experimental Examination of the Effect of Inorganic Salts on Chymotryptic Enantioselectivity in Water

Tao

Rariy

Schmitke

et al. 1999

Biocatalysis and Biotransformation

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Enantioselectivity ( E ) of a-chymotrypsin in the hydrolysis of tropic (3-hydroxy-2-phenylpropionic) acid methyl ester in water was found to be 31 in favor of the R enantiomer. Addition of 1.5 M ammonium or sodium sulfate resulted in a nearly 3-fold drop in the E value. In contrast, thermodynamic calculations predict a 30-40% increase in E. Importantly, these calculations are based on the assumption that the solvent-dependent differences in the desolvation energetics of substrate enantiomers upon formation of their enzyme-bound transition states is the dominant factor by which the solvent affects enzymatic enantioselectivity. Therefore this assuniption, validated previously for enzymatic transesterifications in organic solvents and herein for enzymatic hydrolysis in water, does not apply to concentrated aqueous salt solutions. It is hypothesized instead that the sulfate salts may alter the conformation of chymotrypsin. However, the fluorescence and UV absorbance spectra of the enzyme in water and in l .5 M aqueous salt solutions failed to reveal such changes, suggesting that they must be quite subtle.

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Enzymes in organic synthesis. 35. Stereoselective pig liver esterase catalyzed hydrolyses of 3-substituted glutarate diesters. Optimization of enantiomeric excess via reaction conditions control

Cited by 163 publications

References 0 publications

Lipase-Catalyzed Kinetic Resolution of 1-(2-Hydroxycyclohexyl)Indoles in Batch and Continuous-Flow Systems

Lipase-Catalyzed Kinetic Resolution of 1-(2-Hydroxycyclohexyl)Indoles in Batch and Continuous-Flow Systems

Réactions enzymatiques en chimie organique: 5 ‐ estérifications compétitives

Computational and Experimental Examination of the Effect of Inorganic Salts on Chymotryptic Enantioselectivity in Water

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