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1.
Raquel F. P. Nogueira Ronaldo A. Pilli Nelson durÁn 《Applied biochemistry and biotechnology》1992,33(3):169-176
Growth of the ascomyceteChrysonilia sitophila during degradation of lignin model dimers and monomers was compared to a glucose control. An inhibition of growth by Cα-carbonyl
monomers and stimulation by β-O-4 lignin model and vanillyl alcohol were observed. A comparison of the degradation by this
ascomycete with the basidiomycetePhanerochaete chrysosoporium showed similarities in relation to the type of degradation caused. 相似文献
2.
Venkata Rami Reddy Vaka Jaswanth Kumar Inamadugu Nageswara Rao Pilli Mullangi Ramesh Hussain Reddy Katreddi 《Biomedical chromatography : BMC》2013,27(11):1406-1412
An improved, simple and highly sensitive LC‐MS/MS method has been developed and validated for quantification of febuxostat with 100 μL human plasma using febuxostat‐d7 as an internal standard (IS) according to regulatory guidelines. The analyte and IS were extracted from human plasma via liquid–liquid extraction using diethyl ether. The chromatographic separation was achieved on a Zorbax C18 column using a mixture of acetonitrile and 5 mm ammonium formate (60:40, v/v) as the mobile phase at a flow rate of 0.5 mL/min. The total run time was 5.0 min and the elution of febuxostat and IS occurred at 1.0 and 1.5 min, respectively. A linear response function was established for the range of concentrations 1–6000 ng/mL (r > 0.99). The precursor to product ion transitions monitored for febuxostat and IS were m/z 317.1 → 261.1 and 324.2 → 262.1, respectively. The intra‐ and inter‐day precisions (%RSD) were within 1.29–9.19 and 2.85–7.69%, respectively. The proposed method was successfully applied to pharmacokinetic studies in humans. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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An efficient (in terms of experiment and time) synthetic procedure for chloromethyl methyl ether (MOM-Cl) is described using heteropolyacids as catalysts. 相似文献
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Atmospheric pressure chemical ionization mass (APCI-MS) and tandem mass spectrometry (APCI-MS/MS) is used to probe the mechanism of the Petasis olefination reaction. Oxatitanacycle intermediates 4 were transferred from solution to the gas phase, detected as 4H+ by APCI-MS with characteristic Ti-isotopic patterns, and structurally characterized by APCI-MS/MS. Detection of 4H+, which upon collision activation dissociates to both 3H+ and Cp(2)TiOH+, fully supports the Hughes mechanism as depicted above. [reaction: see text] 相似文献
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[reaction: see text] The addition of the titanium enolates of N-acetyl, N-propionyl, and N-bromoacetyl (R)-oxazolidin-2-ones to gamma-lactol 2, derived from (S)-glutamic acid, afforded trans- and cis-2,5-disubstituted tetrahydrofurans (trans/cis ratio: R = H, 2:1; R = Me, 8:1; R = Br, 10:1) after desilylation with aqueous HF/CH3CN. Chromatographic separation and LiBH4 reduction allowed the efficient preparation of the corresponding trans-2,5-disubstituted tetrahydrofuran diols and the recovery of the chiral auxiliary. 相似文献
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Trimethylsilyl trifluoromethanesulfonate (TMSOTf) catalyzed addition of 1-trimethylsilyloxy-1-phenylethene to N-ethoxycarbonyl-and N-tert-butoxycarbonyl-2-ethoxypiperidines (3d and 3b, respectively) afforded the corresponding ketocarbamates 4a and 4b, in excellent yields. Stereoselective conversion to (±)-norsedamine (7) and (±)-sedamine (8) is described. 相似文献
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An efficient and stereoselective total synthesis of (+/-)-serricornine (1) the sex pheromone produced by the female cigarette beetle Lasioderma serricorne F, is described. (3SR, 5SR, 6SR)-6-Ethyltetrahydro-3,5-dimethyl-2H-pyran-2-one (10) is prepared in 65% yield through lactonization of a 1:1 mixture of C-2 epimers of the corresponding esters. 相似文献
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Described are the first enantioselective total syntheses of (+)-arborescidine A ((+)-1), (-)-arborescidine B ((-)-2), and (-)-arborescidine C ((-)-3), via routes that proceeded in five steps and 50% overall yield, eight steps and 61% overall yield, and nine steps and 51% overall yield, respectively, from 6-bromotryptamine (7). The syntheses feature the use of the Noyori catalytic asymmetric hydrogen-transfer reaction to introduce chirality in dihydro-beta-carbolines 6 and 8. On the basis of an ample precedent from Noyori's work, the reduction produces dihydro-beta-carbolines, and ultimately the natural products, possessing the R absolute configuration. The synthetic arborescidines displayed optical rotations that were opposite in sign those of the natural products, thereby supporting the S configuration for natural arborescidines A (1) and B (2) and the (3S,17S) configuration for natural arborescidine C (3). Our results are in agreement with the initial stereochemical assignment by Pa?s and co-workers, and are counter to their recently revised assignment. 相似文献
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