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1.
Xiao Liang Zhao Wen Guang Jing Shu Ying Han Guang Li Sun Yu Mei Liu Qi Wei Zhang Xiao Jun Ma Zhi Min Wang An Liu 《Phytochemistry letters》2011,4(3):267-270
Two new furostanol saponins, 3-O-[α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-25(R)-furosta-5,22(23)-dien-3β,20α,26-triol (1), 3-O-[β-d-glucopyranosyl-(1→3)-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-20(R)-methoxyl-25(R)-furosta-5,22(23)-dien-3β,26-diol (2) were isolated from the Dioscorea panthaica along with five known steroidal saponins (3–7). The structures of the new saponins were determined by detailed analysis of spectral data (including 2D NMR spectroscopy). The inhibitory activities of the saponins against α-glucosidase were investigated, gracillin (4) and 3-O-[α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-25(R)-furosta-5,20(22)-dien-3β,26-diol (5) were found to exhibit potent activities with IC50 values of 0.11 ± 0.04 mM and 0.09 ± 0.01 mM. 相似文献
2.
Summary Microbial reduction of 6-methyl-5-hepten-2-one (1) and hydrolysis of (±)-sulcatol acetate (4) yielded (S)-(+)-sulcatol (2) and (R)-(-)-sulcatol (5) respectively using Rhizopus arrhizus. 相似文献
3.
Summary
S-[2-Carboxy-1-(1H-imidazol-4-yl)ethyl]-3-mercaptopyruvic acid (I) was chemically synthesized in 15% yield by incubating a reaction mixture oftrans-urocanic acid and 3-fold excess of 3-mercaptopyruvic acid at 45°C for 6 days. The synthesized compound was characterized by fast-atom-bombardment mass spectrometry and high-voltage paper electrophoresis. CompoundI was identified with a product of an enzymatic reaction ofS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-l-cysteine (II) with rat liver homogenate in a phosphate buffer, pH 7.4. CompoundI was degraded toS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-3-mercaptolactic acid (III), a compound previously found in human urine [Kinuta et al. (1994) Biochem J 297: 475–478], by incubation with rat liver homogenate. From these results, we suggest that compoundI is a metabolic intermediate for the formation of compoundIII from compoundII. The present pathway follows a formation of compoundII fromS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl] gluthathione [Kinuta et al. (1993) Biochim Biophys Acta 1157: 192–198], a proposed metabolite ofl-histidine. 相似文献
4.
(±)-(2Z,4E)-α-Ionylideneacetic acid (2) was enantioselectively oxidized to (?)-(l′S)-(2Z,4E)-4′-hydroxy-α-ionylideneacetic acid (3), (+)-(1′R)-(2Z,4E)-4′-oxo-α-ionylideneacetic acid (4) and (+)-abscisic acid (ABA) (1) by Cercospora cruenta IFO 6164, which can produce (+)-ABA and (+)-4′-oxo-α-acid 4. This metabolism was confirmed by the incorporation of radioactivity from (±)-(2-14C)-(2Z,4E)-α-acid 2 into three metabolites. (?)-4′-Hydroxy-α-acid 3 was a diastereoisomeric mixture consisting of major 1′,4′-trance-4′-hydroxy-α-acid 3a and minor 1′,4′-cis-4′-hydroxy-α-acid 3b. These structures, 3a and 3b, were confirmed by 13C-NMR and 1H-NMR analysis. Also, the enantioselectivity of the microbial oxidation was reexamined by using optically pure α-acid (+)-2 and (?)-2, as the substrates. 相似文献
5.
As part of an effort to generate broad-spectrum inhibitors of rhinovirus replication, novel series of (E)-3-[(E)-3-phenylallylidene]chroman-4-ones 1a–e, (E)-3-(3-phenylprop-2-yn-1-ylidene)chroman-4-ones 2a and 2b, (Z)-3-[(E)-3-phenylallylidene]chromans 3a–e, and (E)-3-(3-phenylprop-1-en-1-yl)-2H-chromenes 4a–d were designed and synthesized. All the compounds were tested in vitro for their efficacy against infection by human rhinovirus (HRV) 1B and 14, two representative serotypes for rhinovirus group B and A, respectively. Most of the analogues were found to be potent and selective inhibitors of both HRVs, although HRV 1B was generally more susceptible than HRV 14. Mechanism of action studies of (E)-6-chloro-3-(3-phenylprop-1-en-1-yl)-2H-chromene 4b, the most potent compound on HRV 1B infection, suggested that 4b behaves as a capsid-binder probably acting at the uncoating level. 相似文献
6.
J. Davies R. H. Evans A. A. Francis A. W. Jones D. A. S. Smith J. C. Watkins 《Neurochemical research》1982,7(9):1119-1133
A series of piperidine dicarboxylates (PDA) have been tested for excitatory amino acid agonist and antagonist activity and for synaptic depressant properties in the spinal cords of frogs and immature rats in vitro and of cats in vivo. The substances tested comprised (±)-cis-2,3-PDA, (±)-cis-2,4-PDA, (±)-cis-2,5-PDA, (±)-cis-2,6-PDA, (±)-trans-2,3-PDA, (±)-trans-2,3-PDA and both (+) and (–) forms ofcis-2,3-PDA. Peak excitatory amino acid agonist activity was observed with (±)-trans-2,3- and (±)-trans-2,4-PDA. Excitatory amino acid antagonism and synaptic depressant activity was observed only withcis-dicarboxylates, this activity being greatest in the 2,3-analogue. The agonist actions of piperidine dicarboxylates were effectively depressed by the specific NMDA receptor antagonist, (–)-2-amino-5-phosphonovalerate and, where tested, also byd--aminoadipate and low concentrations of Mg2+. It was concluded that the major part of these agonist actions were mediated by NMDA receptors. The main structural feature of the NMDA agonist actions of these substances was considered to be their close relationship to N-alkyl-aspartic and glutamic acid molecules, with thetrans arrangement of the respective 2,3- and 2,4-situated carboxyl groups promoting most effective interaction with the active sites of the NMDA receptor. (±)-Cis-2,3-PDA depressed excitatory responses induced by NMDA, kainate, quisqualate, (±)-trans-2,3-PDA and (±)-trans-2,4-PDA, or evoked by dorsal root stimulation. Both monosynaptic and polysynaptic excitation were susceptible to the depressant action of this substance. The (–) isomer ofcis-2,3-PDA carried both excitatory amino acid agonist and antagonist activity and also the synaptic depressant properties observed with the racemic form of this substance. The (+) isomer showed little pharmacological activity. It is proposed that the structure-activity features of these heterocyclic amino acids indicate some of the conformational requirements for interaction with physiological excitatory amino acid receptors.This paper is dedicated to Dr. Derek Richter on his seventy-fifth birthday. 相似文献
7.
Tapondjou LA Nyaa LB Tane P Ricciutelli M Quassinti L Bramucci M Lupidi G Ponou BK Barboni L 《Carbohydrate research》2011,346(17):2699-2704
Three new triterpenoid saponins, elucidated as 3-O-β-d-glucopyranosyloleanolic acid 28-O-β-d-xylopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranoside (parkioside A, 1), 3-O-[β-d-apifuranosyl-(1→3)-β-d-glucopyranosyl]oleanolic acid 28-O-[β-d-apifuranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)β-d-xylopyranoside (parkioside B, 2) and 3-O-β-d-glucuronopyranosyl-16α-hydroxyprotobassic acid 28-O-α-l-rhamnopyranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranoside (parkioside C, 3), were isolated from the n-BuOH extract of the root bark of Butyrospermum parkii, along with the known 3-O-β-d-glucopyranosyloleanolic acid (androseptoside A). The structures of the isolated compounds were established on the basis of chemical and spectroscopic methods, mainly 1D and 2D NMR data and mass spectrometry. The new compounds were tested for both radical scavenging and cytotoxic activities. Compound 2 showed cytotoxic activity against A375 and T98G cell lines, with IC50 values of 2.74 and 2.93 μM, respectively. Furthermore, it showed an antioxidant activity comparable to that of Trolox or butylated hydroxytoluene (BHT), used as controls, against 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), oxygen and nitric oxide radicals. 相似文献
8.
Uptake of 3H-labelled (±)-abscisic acid (ABA) into isolated barley (Hordeum vulgare L.) epidermal cell protoplasts (ECP) was followed over a range of pH values and ABA concentrations. The present results show that ABA uptake is not always linearly correlated with the external concentration of undissociated ABA (ABAH). At pH 7.25, ABA uptake exhibited saturation kinetics with an apparent K
m value of 75 mmol·m–3 to tal ABA. This saturable transport component was inhibited by pretreating the protoplasts with 1 mol·m–3
p-chloromercuribenzenesulfonic acid at pH 8.0, conditions that minimized the uptake of this acid sulfhydryl reagent. Moreover, the rate of (±)-[3]HABA uptake was reduced by addition of 0.1 mol·m–3 (±)-ABA to 41%, whereas the same concentration of (±)-ABA was approximately half as effective (46% of the inhibitory effect). Thus, it was concluded that only (±)-ABA competes for an ABA carrier that is located in the epidermal cell plasma membrane. The permeability of the epidermal cell plasma membrane was studied by performing a Collander analysis. At pH 6 the overall plasma-membrane permeability of epidermal cells was similar to that of guard cells but was about two times higher than that of mesophyll cells.Abbreviations ABA
abscisic acid
- ABA–
anion of ABA
- ABAH
undissociated ABA
- 2,4-D
2,4-dichlorophenoxyacetic acid
- DMO
5,5-dimethyloxazolidine-2,4-dione
- ECP
deepidermal cell protoplast
- Kr
partition coefficient
- Mr
relative molecular mass
- NEM
N-ethylmaleimide
- PCMBS
p-chloromercuriben zenesulfonic acid
- Ps
permeability coefficient
We are grateful to Barbara Dierich for expert technical assistance, to Prof. H. Gimmler (Lehrstuhl für Botanik I, Universität Würzburg, FRG) for helpful discussions and to the Deutsche Forschungsgemeinschaft (SFB 251, TP 3) for financial support. 相似文献
9.
A. Meyer J. Schmidt D. Gross E. Jensen A. Rudolph S. Vorkefeld G. Sembdner 《Journal of Plant Growth Regulation》1991,10(1):17-25
The biotransformation of [2-14C](±)9, 10-dihydrojasmonic acid (DJA) was studied in excised shoots of 6-day-old barley seedlings after 72 h. From the ethyl acetate extract, some minor metabolites were isolated and purified by DEAE-Sephadex A-25 chromatography, thin-layer chromatography (TLC), C18-cartridges, and high-performance liquid chromatography (HPLC). The structural identification of these metabolites was performed by gas chromatography-mass spectrometry (GC-MS), circular dichroism (CD), and amino acid analysis, and the following amino acid conjugates were found:N-[(–)9,10-dihydrojasmonoyl]valine,N-[(–)9,10-dihydrojasmonoyl]isoleucine,N-[9,10-dihydrojasmonoyl]leucine,N-[11-hydroxy-9,10-dihydrojasmonoyl]valine,N-[11-hydroxy-9,10-dihydrojasmonoyl]isoleucine,N-[12-hydroxy-9,10-dihydrojasmonoyl]isoleucine; and the cucurbic acid-related compoundsN-{[3-hydroxy-2(4-hydroxypentyl)-cyclopent-1-yl]-acetyl}isoleucine andN-{[3-hydroxy-2(5-hydroxypentyl)-cyclopent-1-yl]-acetyl}isoleucine. The results suggest conjugation with isoleucine and valine, as well as preferential hydroxylation at position C-11 or hydrogenation at position C-6, as being important steps in the metabolism of (±)DJA in barley shoots. 相似文献
10.
Omeje Edwin Ogechukwu Osadebe Patience Ogoamaka Nworu Chukwuemeka Sylvester Amal Hassan Abdessamad Debbab Esimone Charles Okechukwu Akira Kawamura Proksch Peter 《Phytochemistry letters》2011,4(3):357-362
In search of immunomodulatory constituents from the Eastern Nigeria mistletoe, Loranthus micranthus Linn, two new stigmastane steroids: stigmast-7,20 (21)-diene-3β-hydroxy-6-one (1) and 3β-hydroxy-stigmast-23-ene (2); three (two new and one known) lupeol-based triterpenoid esters: 7β,15α-dihydroxyl-lup-20(29)-ene-3β-palmitate (3), 7β,15α-dihydroxyl-lup-20(29)-ene-3β-stearate (4) and 7β,15α-dihydroxyl-lup-20(29)-ene-3β-eicosanoate (5) were isolated and characterized following bioactivity-guided fractionation. The new compounds, 1, 2, 4 and 5 at concentrations of 10, 25 and 100 μg/ml were subjected to cell proliferation and early activation marker (CD69) expression studies in C57Bl/6 mice splenocytes using flow cytometry techniques against Lipopolysaccharide (LPS; 10 μg/ml) and Concanavalin A (ConA; 2 μg/ml) standards. The stigmastane steroids (1 and 2) at the highest concentration of 100 μg/ml showed statistically significantly (p < 0.05) stimulatory activity on the C57B1/6 splenocytes compared to the controls with values of 46 ± 0.76% and 43 ± 0.46% compared to 7.69 ± 0.41% recorded for the negative control. The novel lupeol esters, 4 and 5 at same concentration of 100 μg/ml exhibited lower stimulations of 30 ± 0.41% and 29 ± 0.17% respectively compared to the controls above. The CD69 expression assay at the above doses showed that all the compounds have minimal stimulation. The present study supports the observed immunomodulatory property of the Eastern Nigeria mistletoe and thus confirms the efficacy of this plant in mitigating against wide array of disease conditions orchestrated by immunodeficiency. 相似文献
11.
New analogues of 3β-hydroxy-5α-cholest-8(14)-en-15-one (15-ketosterol) with modified 17-chains [(22S,23S,24S)- and (22R,23R,24S)-3β-hydroxy-24-methyl-22,23-oxido-5α -cholest-8(14)-en-15- ones and (22RS,23ξ,24S)-24-methyl-5α-cholesta-8(14)-ene-3β, 22,23-triol-15-one] were synthesized from (22E,24S)-3β-acetoxy-24-methyl-5α-cholesta-8(14), 22-dien-15-one. The chiralities of their 22 and 23 centers were determined by NMR spectroscopy. The isomeric 22,23-epoxides effectively inhibited cholesterol biosynthesis in hepatoma Hep G2 cells (IC50 0.9±0.2 and 0.7±0.2 μM, respectively), and their activities significantly exceeded those of 15-ketosterol (IC50 4.0±0.5 μM), (22E,24S)-3β-hydroxy-24-methyl-5α-cholesta-8(14),22- dien-15-one (IC50 3.1±0.4 μM), and the 3β,22,23-triol synthesized (IC50 6.0±1.0 μM).__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 3, 2005, pp. 312–319.Original Russian Text Copyright © 2005 by Flegentov, Piir, Medvedeva, Tkachev, Timofeev, Misharin. 相似文献
12.
13.
Hsu FL Yang LM Chang SF Wang LH Hsu CY Liu PC Lin SJ 《Applied microbiology and biotechnology》2007,74(3):659-666
Preparative-scale fermentation of gallic acid (3,4,5-trihydroxybenzoic acid) (1) with Beauveria sulfurescens ATCC 7159 gave two new glucosidated compounds, 4-(3,4-dihydroxy-6-hydroxymethyl-5-methoxy-tetrahydro-pyran-2-yloxy)-3-hydroxy-5-methoxy-benzoic
acid (4), 3-hydroxy-4,5-dimethoxy-benzoic acid 3,4-dihydroxy-6-hydroxymethyl-5-methoxy-tetrahydro-pyran-2-yl ester (7), along with four known compounds, 3-O-methylgallic acid (2), 4-O-methylgallic acid (3), 3,4-O-dimethylgallic acid (5), and 3,5-O-dimethylgallic acid (6). The new metabolite genistein 7-O-β-D-4″-O-methyl-glucopyranoside (8) was also obtained as a byproduct due to the use of soybean meal in the fermentation medium. The structural elucidation of
the metabolites was based primarily on 1D-, 2D-NMR, and HRFABMS analyses. Among these compounds, 2, 3, and 5 are metabolites of gallic acid in mammals. This result demonstrated that microbial culture parallels mammalian metabolism;
therefore, B. sulfurescens might be a useful tool for generating mammalian metabolites of related analogs of gallic acid (1) for complete structural identification and for further use in investigating pharmacological and toxicological properties
in this series of compounds. In addition, a GRE (glucocorticoid response element)-mediated luciferase reporter gene assay
was used to initially screen for the biological activity of the 6 compounds, 2–6 and 8, along with 1 and its chemical O-methylated derivatives 9–13. Among the 12 compounds tested, 11–13 were found to be significant, but less active than the reference compounds of methylprednisolone and dexamethasone. 相似文献
14.
Abscisic acid (ABA) in extracts of somatic embryos and seeds of Gloryvine (Vitis vinifera L.xV. rupestris Scheele) was measured by gas chromatography-mass spectrometry-selected ion monitoring using deuterated ABA, (±)-[C-3Me-2H3]ABA, ([2H3]ABA) as internal standard. The ABA content increased rapidly during embryogeny (0.035 ng/embryo at the globular stage to 0.22 ng/embryo at the mature stage). The level of ABA in the tissues of somatic embryos, expressed in ng/mg dry weight, decreased from the globular stage (0.76 ng/mg) to the mature stage (0.25 ng/mg). Chilling (4° C) induced normal germination of seeds and mature somatic embryos and precocious germination of globular, heart-shaped and torpedoshaped somatic embryos. In all cases chilling led to a marked reduction in endogenous ABA. Exogenous (±)-ABA inhibited the germination of chilled somatic embryos.Abbreviations ABA
abscisic acid
- [2H3]ABA
(±)-[C-3Me-2H3]-abscisic acid
- BHT
2,6-di-t-butyl-4-methylphenol
- GC-MS
gas chromatography-mass spectrometry
- Me-ABA and Me-[2H3]ABA
methyl esters of ABA and [2H3]ABA, respectively
- SIM
selected ion monitoring 相似文献
15.
Bum-Yeol Hwang Minho Cha Hyung-Yeon Park Byung-Gee Kim 《Biotechnology and Bioprocess Engineering》2011,16(4):625-630
Benazepril is a medication used to treat hypertension, congestive heart failure and chronic renal failures. A benazepril intermediate
was synthesized through asymmetric synthesis using aromatic aminotransferase from Enterobacter sp. BK2K-1 (AroATEs). Sodium 4-methoxy-4-(2-nitrophenyl)-2-oxobutanoate (1) and (E)-4-(2-nitrophenyl)-2-oxobut-3-enoic acid (2) were tested as amino acceptors for the transamination by AroATEs. The AroATEs showed higher activity towards 1, which could be explained using a docking simulation. Both the substrate and product inhibitions for the reaction of 1 as an amino acceptor and l-glutamate as an amino donor were examined. The product inhibition by α-ketoglutarate was able to be solved by the removal
of the product using the glutamate dehydrogenase (GDH) and formate dehydrogenase (FDH) coupling system. Using 50 mM of 1, above 99% conversion (> 99% ee) was achieved using the AroATEs, with the GDH and FDH combined system. 相似文献
16.
Phytochemical investigation of the underground parts of Liriope graminifolia (Linn.) Baker resulted in the isolation of two new steroidal saponins lirigramosides A (1) and B (2) along with four known compounds. The structures were determined by extensive spectral analysis, including two-dimensional (2D) NMR spectroscopy and chemical methods, to be 3-O-{β-d-xylopyranosyl-(1→3)-α-l-arabinopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→4)]-β-d-glucopyranosyl-(25S)-spirost-5-ene-3β,17α-diol (1), 1-O-[α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyl]-(25R)-ruscogenin (2), 1-O-β-d-xylopyranosyl-3-O-α-l-rhamnopyranosyl-(25S)-ruscogenin (3), 3-O-α-l-rhamnopyranosyl-1-O-sulfo-(25S)-ruscogenin (4), methylophiopogonanone B (5), and 5,7-dihydroxy-3-(4-methoxybenzyl)-6-methyl-chroman-4-one, (ophiopogonanone B, 6), respectively. Compound 1 has a new (25S)-spirost-5-ene-3β,17α-diol ((25S)-pennogenin) aglycone moiety. The isolated compounds were evaluated for their cytotoxic activities against Hela and SMMC-7721 cells. 相似文献
17.
Nguyen Hoai Nam Phan Van Kiem Ninh Khac Ban Nguyen Phuong Thao Nguyen Xuan Nhiem Nguyen Xuan Cuong Christophe Tistaert Bieke Dejaegher Yvan Vander Heyden Joëlle Quetin-Leclercq Do Thi Thao Chau Van Minh 《Phytochemistry letters》2011,4(3):348-352
Two new cycloartane derivatives, macrostachyosides A (1) and B (2), and seventeen known compounds were isolated from the methanol extract of Mallotus macrostachyus leaves. Their structures were elucidated by NMR and MS data. Macrostachyosides A (1) and B (2) showed significant cytotoxic activities on KB (epidermoid carcinoma) and LU-1 (lung adenocarcinoma) human cancer cell lines with IC50 values ranging from 4.31 ± 0.09 to 7.12 ± 0.07 μg/mL. 相似文献
18.
(S)-(?)-Vertinolide 1 was synthesized via the tetronic acid derivative 6 from (S)-(?)-tetrahydro-2-methyl-5-oxo-2-furancarboxylic acid 3. (±)-Vertinolide was also synthesized from (±)-3. 相似文献
19.
Ahn SM Rho HS Baek HS Joo YH Hong YD Shin SS Park YH Park SN 《Bioorganic & medicinal chemistry letters》2011,21(24):7466-7469
A novel kojic acid derivative containing a trolox moiety, (±)-5-hydroxy-4-oxo-4H-pyran-2-yl methyl 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylate (3a), was synthesized. The two biologically active compounds, namely, kojic acid and trolox, were conjugated via an ester bond as they are expected to behave synergistically. The antioxidant activity and the tyrosinase inhibitory activity of this novel kojic acid derivative on melanogenesis were evaluated. Compound 3a exhibited potent tyrosinase inhibitory activity and radical scavenging activity. Limited structure–activity relationship (SAR) investigations indicated that the tyrosinase inhibitory activities may originate from the kojic acid moiety, and the radical scavenging activity may be due to the phenolic hydroxyl group of trolox. Compound 3a also exhibited potent depigmenting activity in a cell-based assay. The limited SAR investigations revealed that the depigmenting activity of 3a may be due to the synergistic activities of kojic acid and its trolox moiety. 相似文献
20.
《Biocatalysis and Biotransformation》2013,31(5-6):285-289
AbstractTo clarify the structures of biotransformation products and metabolic pathways, the biotransformation of monoterpenoids, (+)- and (?)-camphorquinone (1a and b), has been investigated using Aspergillus wentii as a biocatalyst. Compound 1a was converted to (?)-(2S)-exo-hydroxycamphor (2a), (?)-(2S)-endo-hydroxycamphor (3a), (?)-(3S)-exo-hydroxycamphor (4a), (?)-(3S)-endo-hydroxycamphor (5a), and (+)-camphoric acid (6a). Compound 1b was converted to (+)-(2R)-exo-hydroxycamphor (2b), (+)-(2R)-endo-hydroxycamphor (3b), (+)-(3R)-exo-hydroxycamphor (4b), (+)-(3R)-endo-hydroxycamphor (5b), and (?)-camphoric acid (6b). Compound 1a mainly produced 2a (65.0%) with stereoselectivity, whereas 1b afforded 3b (84.3%) with high stereoselectivity. These structures were confirmed by gas chromatography–mass spectrometry, infrared, 1H nuclear magnetic resonance (NMR), and 13C NMR spectral data. The products illustrate the marked ability of A. wentii for enzymatic oxidation and ketone reduction. 相似文献