نتایج جستجو برای: dynamic 1h nmr
تعداد نتایج: 482449 فیلتر نتایج به سال:
We demonstrated here a facile and efficient synthesis of polyhedral oligomeric silsesquioxane-based amphiphilic polymer by thiol-ene click chemistry. The properties of polyhedral oligomeric silsesquioxane (POSS)–PEG amphiphilic polymers were studied in detail by a combination of 1H NMR, 13C NMR, 29Si NMR FT-IR, GPC, and TG analysis. The newly-designed thiol-ene protocol obtains only anti-Markov...
A recently proposed protocol enables the acquisition of two-dimensional nuclear magnetic resonance (2D NMR) spectra within a single scan. A promising application opened up by this new data acquisition mode concerns its combination with active nuclear polarization methods, whereby spectroscopy is carried out on analytes whose spin magnetizations have been significantly enhanced over their Boltzm...
Radix Astragali is a component of several traditional medicines used for the treatment of type 2 diabetes in China. Radix Astragali is known to contain isoflavones, which inhibit α-glucosidase in the small intestines, and thus lowers the blood glucose levels. In this study, 21 samples obtained from different regions of China were extracted with ethyl acetate, then the IC50-values were determine...
Bioassay-guided fractionation of a CHCl3 extract of the leaves of Xanthium italicum Moretti led to the isolation of four xanthanolides: xanthatin (1), 4-epixanthanol (2), 4-epi-isoxanthanol (3), and 2-hydroxyxanthinosin (4). Their structures were determined by means of 1D and 2D NMR spectroscopy, including 1H-1H COSY, NOESY, HSQC and HMBC experiments, which resulted in complete and unambiguous ...
Four new prenylxanthones, emerixanthones A-D (1-4), together with six known analogues (5-10), were isolated from the culture of the deep-sea sediment derived fungus Emericella sp. SCSIO 05240, which was identified on the basis of morphology and ITS sequence analysis. The newstructures were determined by NMR (1H, 13C NMR, HSQC, HMBC, and 1H-1H COSY), MS, CD, and optical rotation analysis. The ab...
The data included in this paper are associated with the research article entitled "Sesquiterpenoids from the cultured mycelia of Ganoderma capense" [1]. 1H NMR, 13C NMR, DEPT, HSQC, 1H-1H COSY, HMBC, NOESY, HRESIMS, and IR spectra of Ganodermanol A-H (1-11), together with Mo2(AcO)4-induced CD spectrum of Ganodermanol A, CD spectra of Ganodermanol D-E were included in the Data in Brief article. ...
Proton-detected 1H-13C heteronuclear correlated spectroscopy [( 1H,13C]-COSY) was used to establish relations between the carbon-13 and proton nuclear magnetic resonance chemical shifts in the hexadeoxynucleoside pentaphosphate d-(GCATGC)2. Using the previously established sequence-specific proton NMR assignments, sequence-specific assignments were thus obtained for nearly all proton-bearing ca...
BACKGROUND AND AIMS Plausible reasons for the failure of liver graft in liver transplantation are explored. 1H-NMR spectroscopy of serum is employed for assessment of liver graft function. Differences in concentrations of specific metabolites between patients with successful and unsuccessful liver grafts following transplantation were used as possible markers to assess the graft quality. METH...
The C-8-(S) isomer of deoxyloganic acid (7-deoxyloganic acid), together with beta-sitosteryl glucoside, five known stereoisomeric pentacyclic oxindole alkaloids and the tetracyclic oxindole isorhyncophylline, were isolated from the inner bark of Uncaria tomentosa. Structures of the isolated compounds were based on 1H and 13C NMR data, mainly 2D NMR experiments, including 1H-13C HMBC and 1H-1H N...
We show herein how the proton magnetization enhanced by dynamic nuclear polarization (DNP) can be efficiently transferred at moderate magic-angle spinning (MAS) frequencies to half-integer quadrupolar nuclei, S ≥ 3/2, using Dipolar-mediated Refocused Insensitive Nuclei Enhanced Polarization Transfer (D-RINEPT) technique, in which a symmetry-based recoupling scheme built from adiabatic inversion...
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