- Enzyme-catalysed regio- and enantioselective preparative scale synthesis of (S)-2-hydroxy alkanones
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α-Hydroxy alkanones were synthesised with high enantiomeric purity by stereoselective enzyme-catalysed diketone reduction. Both diketone reduction and cofactor regeneration were accomplished with purified carbonyl reductase from Candida parapsilosis (CPCR2). The reaction products were isolated by column chromatography and analysed by chiral GC measurements, 1H-NMR spectroscopy and determination of optical rotations. Preparative-scale biotransformations yielded 350-600 mg of pure aliphatic α-hydroxy ketones including the difficult to obtain (S)-2-hydroxypentane-3-one. For all the products good enantiomeric excesses in the range of 89-93% were achieved.
- Loderer,Ansorge-Schumacher
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p. 38271 - 38276
(2015/05/13)
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- Biocatalytic production of alpha-hydroxy ketones and vicinal diols by yeast and human aldo-keto reductases
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The α-hydroxy ketones are used as building blocks for compounds of pharmaceutical interest (such as antidepressants, HIV-protease inhibitors and antitumorals). They can be obtained by the action of enzymes or whole cells on selected substrates, such as diketones. We have studied the enantiospecificities of several fungal (AKR3C1, AKR5F and AKR5G) and human (AKR1B1 and AKR1B10) aldo-keto reductases in the production of α-hydroxy ketones and diols from vicinal diketones. The reactions have been carried out with pure enzymes and with an NADPH-regenerating system consisting of glucose-6-phosphate and glucose-6-phosphate dehydrogenase. To ascertain the regio and stereoselectivity of the reduction reactions catalyzed by the AKRs, we have separated and characterized the reaction products by means of a gas chromatograph equipped with a chiral column and coupled to a mass spectrometer as a detector. According to the regioselectivity and stereoselectivity, the AKRs studied can be divided in two groups: one of them showed preference for the reduction of the proximal keto group, resulting in the S-enantiomer of the corresponding α-hydroxy ketones. The other group favored the reduction of the distal keto group and yielded the corresponding R-enantiomer. Three of the AKRs used (AKR1B1, AKR1B10 and AKR3C1) could produce 2,3-butanediol from acetoin. We have explored the structure/function relationships in the reactivity between several yeast and human AKRs and various diketones and acetoin. In addition, we have demonstrated the utility of these AKRs in the synthesis of selected α-hydroxy ketones and diols.
- Calam, Eduard,Porté, Sergio,Fernández, M. Rosario,Farrés, Jaume,Parés, Xavier,Biosca, Josep A.
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p. 195 - 203
(2013/05/08)
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- Promiscuous substrate binding explains the enzymatic stereoand regiocontrolled synthesis of enantiopure hydroxy ketones and diols
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Regio- and stereoselective reductions of several diketones to afford enantiopure hydroxy ketones or diols were accomplished using isolated alcohol dehydrogenases (ADHs). Results could be rationalised taking into account different (promiscuous) substrate-binding modes in the active site of the enzyme. Furthermore, interesting natural cyclic diketones were also reduced with high regio- and stereoselectivity. Some of the 1,2 and 1,3-diketones used in this study were reduced by employing a low excess of the hydrogen donor (2-propanol) due to the quasi-irreversibility of these ADH-catalysed processes. Thus, using lower quantities of co-substrate, scale-up could be easily achieved.
- Kurina-Sanz, Marcela,Bisogno, Fabricio R.,Lavandera, Ivan,Orden, Alejandro A.,Gotor, Vicente
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experimental part
p. 1842 - 1848
(2011/02/25)
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- Total synthesis of pteridic acids A and B
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A convergent synthesis of pteridic acids A and B, epimeric spiroacetal polyketides with potent plant growth promoter properties, is described. The use of boron aldol methodology efficiently achieved the stereocontrolled construction of advanced C1-C11 and
- Paterson, Ian,Anderson, Edward A.,Findlay, Alison D.,Knappy, Christopher S.
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p. 4768 - 4777
(2008/09/20)
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- A male-produced aggregation pheromone blend consisting of alkanediols, terpenoids, and an aromatic alcohol from the cerambycid beetle Megacyllene caryae
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Bioassays conducted with a Y-tube olfactometer provided evidence that both sexes of the cerambycid beetle Megacyllene caryae (Gahan) were attracted to odor produced by males. Odor collected from male M. caryae contained eight male-specific compounds: a 10:1 blend of (2S,3R)- and (2R,3S)-2,3-hexanediols (representing 3.2±1.3% of the total male-specific compounds), (S)-(-)-limonene (3.1±1.7%), 2-phenylethanol (8.0±2.4%), (-)-α-terpineol (10.0±2.8%), nerol (2.1±1.5%), neral (63.3±7.3%), and geranial (8.8±2.4%). Initial field bioassays determined that none of these compounds was attractive as a single component. Further field trials that used a subtractive bioassay strategy determined that both sexes were attracted to the complete blend of synthetic components, but the elimination of any one component resulted in a decline in trap captures. Blends that were missing (2S,3R)-2,3-hexanediol, (2R,3S)-2,3-hexanediol, or citral (a 1:1 mixture of neral and geranial) attracted no more beetles than did controls. A pheromone blend of this complexity, composed of alkanediols, terpenoids, and aromatic alcohols, is unprecedented for cerambycid species.
- Lacey, Emerson S.,Moreira, Jardel A.,Millar, Jocelyn G.,Hanks, Lawrence M.
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p. 408 - 417
(2008/09/18)
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- Asymmetric reduction of α-keto esters and α-diketones with a bakers' yeast keto ester reductase
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Optically pure α-hydroxy esters and α-hydroxy ketones have been synthesized by the reduction of the corresponding ketones with a keto ester reductase isolated from bakers' yeast (YKER-I). The reduction of α-keto esters affords the corresponding (S)- or (R)-hydroxy esters selectively, where the stereochemical course depends on the chain length of the alkyl substituent on the carbonyl group. An α-keto short alkanoic ester affords the corresponding (S)-hydroxy ester, whereas a long alkanoate yields the corresponding (R)-hydroxy ester. The reduction of α-diketones affords the corresponding (S)-2-hydroxy ketones regio- and stereoselectively.
- Kawai, Yasushi,Hida, Kouichi,Tsujimoto, Munekazu,Kondo, Shin-Ichi,Kitano, Kazutada,Nakamura, Kaoru,Ohno, Atsuyoshi
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- Biosynthesis of tetronasin: Part 7. Preparation of structural analogues of the tetraketide biosynthetic precursor to tetronasin
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The preparation of three structural analogues of the putative tetraketide biosynthetic precursor (2) of the acyl tetronic acid ionophore tetronasin, as N-acetylcysteamine thioesters (3), (4) and (5) is described. Two examples are 19F-labelled.
- Less, Simon L.,Leadlay, Peter F.,Dutton, Christopher J.,Staunton, James
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p. 3519 - 3520
(2007/10/03)
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