نتایج جستجو برای: h nmr
تعداد نتایج: 578829 فیلتر نتایج به سال:
The complete assignments of the (1)H and (13)C NMR spectra of the hallucinogenic neoclerodane diterpenoid salvinorin A were determined in three different NMR solvents using HSQC, HMBC and COSY. Solvent systems are described that allow the resolution of all (1)H signals. Virtual coupling was observed for the protons at C-2, C-3 and C-4 in the 600 MHz (1)H spectrum in CDCl(3). The complete assign...
Nanoporous sodium montmorillonite clay (Na+-MMT) was used as a support for the immobilization of 1-methyl-3-(trimethoxysilylpropyl)-imidazolium hydrogen sulfate (Na+-MMT-[pmim]HSO4). This catalyst showed excellent catalytic activity for the preparation of 2-amino-3-cyano-5-oxo-5,6,7,8-tetrahydro-4H-benzopyrans via three-component reactions betw...
The first application of high field NMR spectroscopy (800 MHz for (1)H observation) to human hepatic bile (as opposed to gall bladder bile) is reported. The bile sample used for detailed investigation was from a donor liver with mild fat infiltration, collected during organ retrieval prior to transplantation. In addition, to focus on the detection of bile acids in particular, a bile extract was...
195Pt and 1H NMR has been used to show that addition of chlorine and bromine to [Pt(CN)4]2_ in presence of perchloric acid in water results in cyanide and water scrambling with formation of eleven complexes of the type [Pt(CN)4-nCl(H2O)n+1](n-1)+ (n=0, 1, 2, 3, 4). Addition of NBu4OH ...
The interaction between hydronium ion and several crown ethers was studied via conductometry in nitromethane at 25 °C and 1H-NMR techniques. The stabilities of the resulting 1:1 complexes were determined from the conductance data and found to vary in the order DC18C6 > 18C6 > DB30C10 > DB24C8 > DB18C6 > ~B15C5 > DB21C7. For the first time, evidences for the formation of a 2:1 san...
60%; [a]25D -13.4O (c 0.7, MeOH);24 'H NMR (CDCld 8 0.95 (3 H, d, J = 6.0 Hz), 1.40-2.00 (3 H, m), 2.15 (2 H, br s), 3.30-3.90 (4 H, m). Synthesis of 10. This compound was synthesized by starting from cis-3Dc as reported above for cis-3Ac. The diastereomeric ratio has been obtained by capillary GC analysis (150 OC 0 min/4 OC/min/250 OC 5 min, tR = 13.72 (major), 14.10 (minor)). The yield is rep...
Background and objectives: Heracleum persicum (Golpar)is a native medicinal plant of Iran which belongs to Apiaceae family. The fruits of the plant have been used as spice for flavoring. They have also showed carminative, antioxidant, anticonvulsant, analgesic, anti-inflammatory, immunomodulatory and cytotoxic properties. In this study, toxicity of different fractions ...
پیوندهای هیدروژنی، به عنوان عامل کنترل کننده بسیاری از فرایندهای شیمیایی و بیوشیمیایی، پدیده شناخته شده ای محسوب می شوند. تعیین خواص دقیق این پیوندها به علت گسترده بودن برهمکنش-هایی که جزء پیوندهای هیدروژنی محسوب می شوند بسیار مشکل است. در این تحقیق با استفاده از روش های dft خواص پیوندهای هیدروژنی از نوع n-h...cl، n-h…o و o-h…cl در سه نمک آلانین هیدروکلرید، تریونین هیدروکلرید و سیستئین هیدروکلر...
High-resolution (1)H NMR spectroscopy of body fluids has proved to be very useful in diagnostics of inherited metabolic diseases, whereas (13)C NMR remains almost unexploited. In this paper the application of (13)C NMR spectroscopy of fivefold concentrated urine samples for diagnosis of selected metabolic diseases is reported. Various marker metabolites were identified in test urine samples fro...
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