tetrahydrobenzo[b]pyran derivatives 1 were utilized for the synthesis of several new pyrano[2,3-d]pyrimidine derivatives 2. compound 2 was obtained in the presence of ac2o/h2so4 (as a catalyst) and was confirmed by spectroscopic data such as ir, 1h nmr and 13c nmr. ab initio calculation was carried out to study geometric optimization, thermodynamic parameters, aromaticity and dynamic process of...

hartree-fock (hf) and density functional theory (dft) methods employed to study the effect of conformational change on the 13c chemical shifts of 6-mono axial and equatorial substituted and 6,7-di axial-axial, equatorial-equatorial and axial-equatorial substitutedderivatives of 5,6,7,8-tetrahydrodibenzo[a,c]cyclo-octene. the geometry of the conformers have been optimized in the gas phase employ...

13C NMR of isotopically enriched metabolites has been used to study the metabolism of Microbacterium ammoniaphilum, a bacterium which excretes large quantities of L-glutamic acid into the medium. Biosynthesis from 90% [1-13C]glucose results in relatively high specificity of the label, with [2,4-13C2]glutamate as the major product. The predominant biosynthetic pathway for synthesis of glutamate ...

The X-ray structure of the title compound has been determined for first time. Data on its 1H–13C-NMR coupling constants and 15N-NMR spectrum are also given.

X-ray crystallography was used to characterise the title compound for first time, and 1H NMR, 13C NMR IR spectroscopic data from earlier reports were also updated.

Low-temperature 15N and 13C CP/MAS (cross-polarization/magic angle spinning) NMR has been used to analyze BChl-histidine interactions and the electronic structure of histidine residues in the light-harvesting complex II (LH2) of Rhodopseudomonas acidophila. The histidines were selectively labeled at both or one of the two nitrogen sites of the imidazole ring. The resonances of histidine nitroge...

in this research, the microstructural of low molecular weight 1,2-polybutadiene (1,2-pbd) was conducted by 1h and 13c nuclear magnetic resonance spectroscopy (nmr) to determine the isomeric contents of 1,4-cis, 1,4-trans and 1,2-vinyl in 1,2-pbd polymer structures. number average molecular weight for low molecular weight 1,2-pbd was measured by nmr techniques and the results were compared with ...

13C-NMR, Apigenin, Kaempferol, Flavonoid, Biosynthesis Cell suspension cultures of parsley (Petroselinum hortense) were incubated with [l,2-13C2]acetate during a period of active flavonoid production. The flavonoid glycosides were extracted with ethanol, hydrolyzed in dilute acid, and the aglycones purified by chromatography. Apigenin, a flavone, and kaempferol, a flavonol, were analyzed at 67....

Isoprenoid biosynthesis was investigated in the green alga Scenedesmus obliquus grown heterotrophically on 13C-labelled glucose and acetate. Several isoprenoid compounds were isolated and investigated by 13C-NMR spectroscopy. According to the 13C-labelling pattern indicated by the 13C-NMR spectra, the biosynthesis of all plastidic isoprenoids investigated (prenyl side-chains of chlorophylls and...

In situ solid-state NMR methodologies have been used to investigate the photocatalytic oxidation of ethanol (CH3CH2OH) over a series of SnO2-based photocatalysts. The adsorption of ethanol on commercially available SnO2 powder was studied using both cross-polarization 13C NMR and REDOR experiments, and showed the formation of two surface ethanol species, hydrogen-bonded ethanol at surface hydro...