نتایج جستجو برای: oxidative nmr
تعداد نتایج: 186206 فیلتر نتایج به سال:
dried aceton-chloroform extract of aerial parts of euphorbia spinidens bornm. ex prokh. endemic to iran, yielded two new triterpenoids, lup-20(29)-ene-33, 28 diol commonly known as betulin and (3β,23e)-cycloarta-23-ene-3,25-diol. the structures of the isolated compounds were elucidated by 13 c- and 1 h-nmr as well as 2d-nmr, ir and by the aid of mass fragmentation pattern. in phagocyte chemilum...
The worldwide heparin contamination crisis in 2008 led health authorities to take fundamental steps to better control heparin manufacture, including implementing appropriate analytical and bio-analytical methods to ensure production and release of high quality heparin sodium product. Consequently, there is an increased interest in the identification and structural elucidation of unusually modif...
Abstract Polyethyleneimine (PEI)/silica adsorbents have been considered as a promising candidate for post-combustion CO2 capture, but the limited process study has performed on pilot-scale unit. Herein we report 150 h continuous test results using 100 kg sample of silica-PEI fluidized bed The removal efficiency and dynamic sorption capacity were evaluated continuously by changing number variabl...
Z. Naturforsch. 38b, 1069-1071 (1983); received May 13, 1983 Pseudohalogens, IR Spectra, Nickel The title compound reacts with cyanogen halides, XCN (X = Br or I) to give the complexes L2(X)(CN)Ni (L = P(OPh)3, X = Br or I). The oxidative addition of (SCN)2 and (SeCN)2 to the same compound results in the formation of L2Ni(XCN)2 (X = S or Se). All the complexes have been characterized by element...
Two flavonoids, 4,2',5'-trihydroxy-4'-methoxychalcone (1) and (2S)-6,7,4'-trihydroxyflavan (2), along with fourteen known flavonoids and two other known arylbenzofurans were isolated from the heartwood of Dalbergia odorifera. The structure of compounds 1 and 2 were established by spectroscopic (NMR and MS) analyses. Of the isolates, eight compounds (1, 4, 7, 10, 12, 14, 15, 17) were found to ha...
A pentabenzopentaaza[10]circulene has been synthesized as the largest fully conjugated hetero[n]circulene via a fold-in oxidative fusion reaction of an ortho-phenylene-bridged cyclic pyrrole pentamer. This circulene takes saddle-distorted structure with bond lengths central ten-membered-ring in range 1.455–1.493 Å. Relatively broad absorption and fluorescence spectra were observed, which reflec...
Two novel squalene-derived triterpenes, spirodehydrovenustatriol (3) and 14-keto-dehydrothyrsiferol (4) were isolated from the red alga Laurencia viridis, together with two new and unusual C(17) terpenoids, adejen A (5) and B (6). These truncated structures possess structural similarities with other known squalene metabolites and their biogenetic origin has been proposed on the basis of an oxid...
Sixteen compounds, including two new natural products (1 and 2), were obtained from the twigs of Illicium angustisepalum. The structures were elucidated based on NMR, MS, IR data and optical rotation values. Compounds 4, 5, 6 and 8 displayed moderate antibacterial activities against clinical isolates; compounds 4, 5, 8, 9 and 15 protected neural cells against oxidative stress; and compounds 10 ...
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 to this solution gives (nbu4)2[pt(cn)4cl(oh)]. nmr measurements in acetone also show cyanide and hydroxyl group ...
the dopamine has been studied theoretically at the b3lyp/6-31g* level were performed in gasphase. we calculated physical parameters like atomic charges, energy (=>), asymmetry parameter(?), chemical shift @iso, dipole moment and isotropic nmr determinant and in this work we usedgaussian 03 at nmr and calculation by using b3lyp methods with 6-31g* basis set.
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