A wide range of simple organic substrates has been successfully tritium labelled using reduced platinum oxide as catalyst. Exchange conditions involved reaction temperatures in the range 60-15OoC, and reaction times of 3-7 days. The isotope sources for the reactions were tritium gas and tritiated wa
Heterogeneous palladium-catalyzed exchange labelling of representative organic compounds with tritium gas
β Scribed by Philip G. Williams; Chit Than; Sadegh Rabbani; Mervyn A. Long; John L. Garnett
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- French
- Weight
- 681 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0022-2135
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β¦ Synopsis
Abstract
A range of organic substrates was successfully exchanged with tritium gas using NaBH~4~βreduced palladium oxide or chloride as catalyst. Exchange conditions involved a reaction temperature of 100 Β°C, a reaction time of 3 days, and products were analyzed by radioβgas chromatography and ^3^H NMR spectroscopy. Both aromatic and aliphatic compounds underwent exchange, 18 of the 22 substrates incorporated > 35% of the available tritium, and most products showed high radiochemical purity. ^3^H NMR analyses showed that both alkanes and the alkyl chains of alkylbenzenes were rapidly and evenly labelled. Some aromatic compounds showed general ring exchange while others showed high specificity. These results for bulk palladium catalyst are strikingly different from those obtained with bulk platinum and supported palladium catalysts. The results are discussed in terms of currently accepted mechanisms of heterogeneous metal catalyzed hydrogen isotope exchange reactions.
π SIMILAR VOLUMES
## Abstract In a new approach to the specific labelling of organic compounds with tritium use is made of isotope exchange with tritium of certain specific hydrogen atoms in organic molecules when stirred with tritium gas in solution at room temperature in the presence of a metal hydrogen transfer c
## Abstract The hydrogen isotope exchange of BrefeldinβA with tritium gas (T~2~) in 1,4βdioxane was studied over a commercial palladium catalyst supported on diatomaceous earth (5% metallic weight). The effect of the gas phase was studied. Addition of air in the gas phase led to an increase of the