Isotope-labeling experiments, amine

Isotope-labeling experiments, amine isomerization, 103 Itatonic acid, 28... 

Allylic amide isomerization, 117 Allylic amine isomerization ab initio calculations, 110 catalytic cycle, 104 cobalt-catalyzed, 98 double-bond migration, 104 isotope-labeling experiments, 103 kinetics, 103 mechanism, 103 model system, 110 NMR study, 104 rhodium-catalyzed, 9, 98 Allylnickel halides, 170 Allylpalladium intermediates, 193 Allylsilane protodesilylation, 305 Aluminum, chiral catalysts, 216, 234, 310 Amide dimers, NMR spectra, 282, 284 Amines ... 

However, Boozer and Hammond [7] have obtained additional support for the postulated chain termination via reaction (9) as opposed to reaction (5) on the basis of isotopic labelling experiments and from the inhibiting effect of amines not possessing a labile N—H function in their structure [8]. The use of deuterium-labelled methyl aniline and diphenyl-amine as inhibitors in the oxidation of tetralin and cumene did not show the isotope effect which would be expected if reaction (5) was important. Similarly, both AT-dimethylaniline and AT,AP-tetramethyl-p-phenylene-diamine have measurable inhibitory activity despite the fact that neither has a labile hydrogen [8]. However, it has been argued [12] that neither a kinetic isotope effect nor a labile hydrogen is necessary if inhibition results from an electron transfer reaction of the type... 

The amines of interest, labelled with a stable isotope, are now routinely used as convenient internal standards during mass-fragmentographic measurements. However, the labeled precursors are likely to find an increasing utilization in metabolic studies. Curtius et al. [444] performed mass-fragmentographic measurements of dopamine and the related metabolites in the urine after a metabolic loading experiment with a precursor of such compounds (labeled tyrosine). 

A consideration of Bic possible pathways to account for nucleoside utilization indicated that the results could not be explained deciavely by the formation of hypoxantbine or adenine from the nucleosides. Hypoxanthinc was not a precursor of nucleic acids in the rat (200). Furthermore, free adenine (which might have been formed conceivably from inosine by successive amination and hydrolysis of the hypoxantbine riboside) was not formed from inosine. This was shown by the following experiment a large dose of unlabeled adenine with either labeled inosine or labeled adenosine was administered to rats (211) and 2,8-dioxyadenine, hich was deposited in the kidneys as a result of the administration of a large dose of adenine, was isolated (201, 214), analyzed for isotope content, and found to have trapped only a slight amount of radioactivity from either nucleoside (211). 

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