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121.
122.
以1-甲基吡咯为原料,通过酰化、硝化、酯化、还原、成盐等五步反应,合 成得到1-甲基-2-甲氧羰基-4-氨基吡咯盐酸盐,总产率20%左右。该法具有 原料便宜易得、操作简单、产物易于分离提纯等优点,有利于该化合物的大量制备 和应用。 相似文献
123.
The fully substituted cyclopentenedione core of madindoline A (1) and B (2) as potent and selective inhibitor of IL-6 has been synthesized efficiently. The quaternary carbon center C-2' was constructed on the basis of a newly developed AIEt3-promoted tandem reductive rearrangement of α-hydroxy epoxides. 相似文献
124.
125.
Joris Proost 《Journal of Solid State Electrochemistry》2005,9(10):660-664
A thermodynamic framework has been provided for the interpretation of combined cyclic voltammetry and surface stress measurements, the latter being obtained from wafer curvature or beam deflection measurements of a solid electrode as a function of applied potential (so-called voltstressograms). Firstly, the derivation of electrocapillarity equations for solid electrodes has been critically reviewed by starting from the Gibbs adsorption equation appropriate for solid–electrolyte interfaces. This allowed us to demonstrate the critical importance of elastic surface strain in the thermodynamic boundary conditions of the partial derivatives intervening in the interpretation of voltstressograms. From these considerations, it was shown for the first time that the electrocapillarity equations for solid electrodes are not appropriate for describing the variation of surface stress with potential obtained from wafer curvature measurements, because such measurements are intrinsically incompatible with the constant strain condition implied in the electrocapillarity equations. An alternative explanation is provided for the experimentally observed proportionality between the current density, measured in cyclic voltammograms, and the first derivative of surface stress with respect to potential, obtained from voltstressograms. 相似文献
126.
Martin Fuchs 《manuscripta mathematica》1991,72(1):131-140
Given a smooth domain Ω in ℝ
m+1 with compact closure and a smooth integrable functionh: ℝ
m+1→ℝ satisfyingh(x)≥H
∂Ω
(x) on ∂Ω whereH
∂ω denotes the mean curvature of ∂Ω calculated w.r.t. the interior unit normal we show that there is a setA⊂ℝ
m+1 with the properties
andH
∂A=h on ∂A. 相似文献
127.
《Arabian Journal of Chemistry》2022,15(12):104368
Protein hydrolysates have the potential to be natural and safer sources of bioactive peptides. In this study, two proteases were used to hydrolyze Chinese sturgeon (Acipenser sinensis) protein, and the hydrolysates were then purified to yield antioxidant peptides. The degree of hydrolysis of 23.56 % and 18.14 % was obtained using papain and alcalase 2.4L, respectivly, and hydrolysates had 96.80 % and 87.24 % total amino acid content, respectivly. The papain hydrolysate (PH) and alcalase 2.4L hydrolysate (AH) showed good antioxidant activity against DPPH? (IC50 of 3.64 and 3.15 mg/mL) and ABTS?+ (IC50 of 1.92 and 1.58 mg/mL), respectively. The low-molecular-weight (<1000 Da) fraction of both hydrolysates demonstrated the highest antiradical activity (IC50 of 2.59 and 2.31 mg/mL, DPPH) and (IC50 of 1.54 and 1.36 mg/mL, ABTS), respectively. Nine peptides were separated from both hydrolysates using reverse phase high performance liquid chromatography (RP-HPLC). The IC50 for ABTS?+ scavenging activity of peptide P5 with valine, glycine and asparagine (MW of 282.13 Da) from PH, and peptide P3 with histidine, glycine and alanine (MW of 302.74 Da) from AH was 0.89 and 0.72 mg/mL, respectively. The fractions and purified peptides obtained from Chinese sturgeon hydrolysates could be utilized as natural antioxidant substitutes in pharmaceuticals and food products. 相似文献
128.
The influence of CCl4 on the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), the value of the
total antioxidant status (TAS), and the concentration of malonic dialdehyde (MDA) and glutathione (GSH) was monitored in plasma
or whole blood of rabbits. The administration of CCl4 caused the increase of the SOD activity to approximately 150 % and the decrease in the activity of GPx and GR by about 50
%. These changes were accompanied with the increase in TAS value and MDA concentration and the decrease of GSH concentration.
The effect of CCl4 was suppressed by the previous 7 days lasting or simultaneous administration of vitamin E. Oxidative stress caused by CCl4 was accompanied by the development of reactive oxygen forms, especially superoxide radical anion. 相似文献
129.
Mariko Kitajima 《Tetrahedron letters》2006,47(19):3199-3202
A new pyrrolidinoindoline-type alkaloid, CPC-1, and a new tryptamine-derived dimeric alkaloid, CPC-2, were isolated from the seeds and rinds of Chimonanthus praecox f. concolor. The structure including the absolute configuration of CPC-1 was determined by chiral total synthesis. CPC-2 has a unique hexahydropyrroloquinoline skeleton. 相似文献
130.
A new synthetic method for the preparation of allyl amines has been developed. The key steps of this method are enantioselective addition of diethylzinc and [1,3]-chirality transfer through the [3.3] sigmatropic rearrangement of allyl cyanates. Stereocontrolled syntheses of lentiginosine (1) and polyoxamic acid derivative 2 from a common intermediate 7 derived from D-tartaric acid (8), have been accomplished. 相似文献