discovery of 13c nmr and its application in the biosynthetic pathways prompted the synthesis of several 13c labelled precursors. to investigate the metabolism of phenyllactic acid in the solanaceae family, the double labelled acid was synthesized from barium carbonate (13c) and sodium syanide (13c)

Discovery of 13C NMR and its application in the biosynthetic pathways prompted the synthesis of several 13C labelled precursors. To investigate the metabolism of phenyllactic acid in the Solanaceae family, the double labelled acid was synthesized from barium carbonate (13C) and sodium syanide (13C)

We describe a new method for exciting triple-quantum coherences in 13C-labelled powder samples under MAS. The proposed method combines selective double-quantum excitation with rotational resonance and frequency-selective composite pulses. The spin dynamics of this new method are described theoretically. Numerical calculations of the spin dynamics are compared to experimental results on fully 13...

Some aryl and heteroaryl azido compounds were synthesized from the reaction of corresponding fluoro and chloro compounds with sodium azide in DMF as solvent and under various reaction conditions especially ultrasonic irradiation. Reaction of aromatic and heteroaromatic azido compound with thioacetic acid in the presence of sodium hydrogen carbonate and in methanol as solvent led to the differen...

13C nuclear magnetic resonance spectroscopy was used to determine the absolute amounts to de novo synthesized amino acids in both the perchloric acid extracts and the hydrolyzed protein fractions of F98 glioma cells incubated for 2 h with 5 mmol/l [U-13C]glucose. 13C NMR spectra of the hydrolyzed protein fraction revealed a marked incorporation of 13C-labelled alanine, aspartate and glutamate i...

An effective in vitro enzymatic synthesis is described for the production of nucleoside triphosphates (NTPs) which are stereo-specifically deuterated on the H5" position with high selectivity (>98%), and which can have a variety of different labels (13C, 15N, 2H) in other positions. The NTPs can subsequently be employed in the enzymatic synthesis of RNAs using T7 polymerase from a DNA template....

Hyperpolarization turns weak nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) responses into strong signals, so normally impractical measurements are possible. We use parahydrogen to rapidly hyperpolarize appropriate 1H, 13C, 15N, and 31P responses of analytes (such as NH3) and important amines (such as phenylethylamine), amides (such as acetamide, urea, and methacrylamide)...

Tissue cultures o f Pimpinella anisum and P. major were used to study the biosynthesis o f pseudoisoeugenols. The putative precursors were labelled with 13C with one exception that was labelled with i4C. The incorporation o f the label was controlled by 13C N M R and liquid scintil­ lation, respectively. The biosynthetic sequence found was L-phenylalanine, /-cinnamic acid, /?-coumaric acid, / 7...

Time courses of incorporation of 13C from 13C-labelled glucose and/or acetate into the individual carbon atoms of amino acids, citrate and lactate in depolarized cerebral tissues were monitored by using 13C-n.m.r. spectroscopy. There was no change in the maximum percentage of 13C enrichments of the amino acids on depolarization, but the maxima were reached more rapidly, indicating that rates of...