Gelozymes in organic synthesis. Part IV: Resolution of glycidate esters with crude Mung bean (Phaseolus radiatus) epoxide hydrolase immobilized in gelatin matrix

Devi, Avala Vedamayee; Lahari, Challa; Swarnalatha, Lakshmi; Fadnavis, Nitin W.

doi:10.1016/j.tetasy.2008.01.036

Cited by 14 publications

(9 citation statements)

References 24 publications

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“…Nevertheless, after 100 min of a preparative reaction which was conducted on a 1 g scale at 25 g/L, the remaining (2 S ,3 R )‐ 3 and the formed (2 R ,3 R )‐ 4 were isolated in 47 and 44% yields, and >99 and 94% ee , respectively. Interestingly, the Kau2‐EH proved to be equally efficient13 or compared favorably12,14 with other EHs used in the kinetic resolution of rac ‐ 3 . Essentially the same results as described above have been reported for a gelozyme preparation of the Phaseolus radiatus (Mung bean) EH acting on rac ‐ 3 : the remaining epoxide (2 S ,3 R )‐ 3 and the formed diol (2 R ,3 R )‐ 4 were obtained in isolated yields of 45 and 40% with ee values of >99 and 94%, respectively 13.…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly, the Kau2‐EH proved to be equally efficient13 or compared favorably12,14 with other EHs used in the kinetic resolution of rac ‐ 3 . Essentially the same results as described above have been reported for a gelozyme preparation of the Phaseolus radiatus (Mung bean) EH acting on rac ‐ 3 : the remaining epoxide (2 S ,3 R )‐ 3 and the formed diol (2 R ,3 R )‐ 4 were obtained in isolated yields of 45 and 40% with ee values of >99 and 94%, respectively 13. Furthermore, the remaining epoxide (2 R ,3 S )‐ 3 has been obtained either in 95% ee and 26% yield using whole cells of Pseudomonas sp.…”

Section: Resultsmentioning

confidence: 99%

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Enantioselective Bio‐Hydrolysis of Various Racemic and meso Aromatic Epoxides Using the Recombinant Epoxide Hydrolase Kau2

et al. 2015

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Epoxide hydrolase Kau2 overexpressed in Escherichia coli RE3 has been tested with ten different racemic and meso α,β‐disubstituted aromatic epoxides. Some of the tested substrates were bi‐functional, and most of them are very useful building blocks in synthetic chemistry applications. As a general trend Kau2 proved to be an extremely enantioselective biocatalyst, the diol products and remaining epoxides of the bioconversions being obtained – with two exceptions – in nearly enantiomerically pure form. Furthermore, the reaction times were usually very short (around 1 h, except when stilbene oxides were used), and the use of organic co‐solvents was well tolerated, enabling very high substrate concentrations (up to 75 g/L) to be reached. Even extremely sterically demanding epoxides such as cis‐ and trans‐stilbene oxides were transformed on a reasonable time scale. All reactions were successfully conducted on a 1 g preparative scale, generating diol‐ and epoxide‐based chiral synthons with very high enantiomeric excesses and isolated yields close to the theoretical maximum. Thus we have here demonstrated the usefulness and versatility of lyophilized Escherichia coli cells expressing Kau2 epoxide hydrolase as a highly enantioselective biocatalyst for accessing very valuable optically pure aromatic epoxides and diols through kinetic resolution of racemates or desymmetrization of meso epoxides.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Enantioselective Bio‐Hydrolysis of Various Racemic and meso Aromatic Epoxides Using the Recombinant Epoxide Hydrolase Kau2

et al. 2015

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“…The crude mbEHs were prepared according to the previously reported methods. 11,23 2.3. Preparation of CLEAs of mbEHs and Assay of CLEAs' Activity.…”

Section: Methodsmentioning

confidence: 99%

“…Two novel EHs that have been discovered from mung bean 10,11 were capable of effectively catalyzing enantioconvergent hydrolysis of p-nitrostyrene oxide to (R)-p-nitrophenyl glycol and showed great potential for synthesis of enantiopure chiral vicinal diols that are versatile intermediates for the preparation of pesticides, medicines, and fine chemicals. 5,6,12 However, free EHs are usually sensitive to temperature or pH and difficultly recycled and reused.…”

Section: Introductionmentioning

confidence: 99%

Using Ionic Liquid in a Biphasic System to Improve Asymmetric Hydrolysis of Styrene Oxide Catalyzed by Cross-Linked Enzyme Aggregates (CLEAs) of Mung Bean Epoxide Hydrolases

Wei

et al. 2014

Ind. Eng. Chem. Res.

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The asymmetric hydrolysis of racemic styrene oxide (SO) to (R)-1-phenyl-1,2-ethanediol using cross-linked enzyme aggregates (CLEAs) of epoxide hydrolases (EHs) from mung bean (mbEHs) was successfully conducted using ionic liquids (ILs) as cosolvents in biphasic systems. Of all the tested ILs, the best results were observed in the biphasic system containing [C 4 MIM][PF 6 ] with better biocompatibility to the CLEAs of mbEHs. In the [C 4 MIM][PF 6 ]/buffer biphasic system, it was found that the optimal volume ratio of IL to buffer, reaction temperature, buffer pH, and substrate concentration were 1:5, 40°C, 7.5, and 120 mM, respectively. Under the optimized reaction conditions, the initial reaction rate, yield, product ee, and E value reached 3.35 mmol/min, 49%, 95.8%, and 151, respectively, which were much higher than the corresponding values reported previously. Furthermore, the CLEAs exhibited markedly enhanced operational stability in a [C 4 MIM][PF 6 ]-based biphasic system as compared with an n-hexane-based biphasic system. Additionally, the CLEAs of mbEHs-catalyzed process with the IL [C 4 MIM] [PF 6 ] was shown to be feasible on a 500 mL preparative scale, demonstrating their great potential for biosynthesis of chiral ortho-diols.

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“…Other bifunctional epoxy esters such as some trans-(±)-3-phenyl glycidates have been studied as substrates for EH-mediated reactions [157] in order to obtain the useful chiral synthons ethyl (2S,3R)-trans-3-phenylglycidate and methyl (2S,3R)-trans-3-(4-methoxyphenyl)glycidate, which can be used to gain access to the taxol side chain and Diltiazem, respectively (Figure 8.38). The EH from the mung bean was immobilized in a gelatin gel for this kinetic resolution, and diiso propyl ether was used as an immiscible organic cosolvent to minimize spontane ous hydrolysis of the substrates.…”

Section: Epoxy Estermentioning

confidence: 99%

Epoxide Hydrolases and their Application in Organic Synthesis

2016

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c h a p t e r 8 INTRODUCTIONOrganic chemists have become interested in enzymes as catalysts due to their high efficiencies and specificities. Moreover, recent progress in molecular biology and enzyme-related research areas enabled and simplified the production and purifica tion of recombinant enzymes in large quantities and their engineering toward tailormade biocatalysts using straightforward mutagenesis and screening techniques. This is also true for epoxide hydrolases (EHs), as evidenced by the many published research papers about the synthetic applications of naturally occurring or engi neered EHs. EHs catalyze the opening of oxirane rings, generating a vicinal diol as the final product ( Figure 8.1). From a synthetic chemistry point of view, the most valuable EHs are those with either (i) high enantioselectivities or (ii) a combination of low enantio preference with a high level of enantioconvergence. While the former generate enan tiopure epoxides with a maximum yield of 50% in a kinetic resolution process, the latter produce ideally an enantiopure diol product with a theoretical yield of 100%. Thus, EHs provide convenient access to enantiopure epoxides or diols from racemic epoxides. Furthermore, the enantiopure diols can then often be chemically trans formed back to the corresponding epoxides with no effect on the enantiomeric excess (ee). High values of enantioselectivity or enantioconvergence are a consequence of particular enzyme-substrate interactions, which can be modulated by specific reac tion conditions or through the exchange of specific amino acids of the biocatalyst. The final stereochemical outcome of an EH-catalyzed reaction depends solely on the regioselectivity coefficients, which determine the absolute configuration and the ee of the diol product when the reaction reaches 100% conversion. During the reaction, the oxirane ring of each enantiomer is often attacked at either carbon atom, resulting in a mixture of diol enantiomers (Figure 8.2). Unfortunately, several authors used the product-derived E-value, E P (calculated from c and ee P using Sih's equation; see Ref.[1]) for characterizing the stereochemistry of the diol formation of an EH-mediated hydrolysis reaction [2,3]. This is wrong and misleading for epoxide-opening reac tions since there are two possible positions of attack for each oxirane enantiomer. The ideal enantioconvergent EH leads to deracemization of a racemic mixture of an epox ide and exhibits reversed regioselectivity for either substrate enantiomer, that is,

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Gelozymes in organic synthesis. Part IV: Resolution of glycidate esters with crude Mung bean (Phaseolus radiatus) epoxide hydrolase immobilized in gelatin matrix

Cited by 14 publications

References 24 publications

Enantioselective Bio‐Hydrolysis of Various Racemic and meso Aromatic Epoxides Using the Recombinant Epoxide Hydrolase Kau2

Enantioselective Bio‐Hydrolysis of Various Racemic and meso Aromatic Epoxides Using the Recombinant Epoxide Hydrolase Kau2

Using Ionic Liquid in a Biphasic System to Improve Asymmetric Hydrolysis of Styrene Oxide Catalyzed by Cross-Linked Enzyme Aggregates (CLEAs) of Mung Bean Epoxide Hydrolases

Epoxide Hydrolases and their Application in Organic Synthesis

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