Synthesis of 14C-labeled

C-F-IMF, 170, containing famesyl moiety labelled with 14C, has been obtained involving the synthesis of 14C-labelled famesol [14C-F, 173] from ketone 174 (equation 60). 169 and 170 have been synthesized in order to clear the pharmacokinetic profile of these drugs in vivo and in vitro. 

Scrivens WA, Tour, J, Creek, K, Pirisi, L (1994) Synthesis of 14C-labeled C60, its suspensions in water. Preparation and Characterization. J.American Chemical Society 116, 4517—4518. 

Carbon-14 is usually produced in the form of barium carbonate which is therefore the starting point for the synthesis of 14C-labelled compounds fortunately, many such compounds at high specific activity are now available commercially. The isotope emits only /8-rays the maximum energy of which is about 0.15 MeV the rays are therefore only feebly penetrating and for this reason the radiation hazard in work with carbon-14 is small but special methods of assay are required to achieve great sensitivity. The most important of the assay procedures are ... 

The 5,6-O-isopropylidene acetal (152) of L-ascorbic acid has been prepared,340 and von Schuching and Frye341 prepared the corresponding cyclohexylidene acetal. These compounds were found to be more resistant than L-ascorbic acid toward oxidation, and the parent acid can be readily regenerated by acid hydrolysis. The derivative was used in the synthesis of 14C-labeled vitamin C. The C-2 and C-3 enols of L-ascorbic acid or its acetone derivative (152) can be readily methylated with diazomethane, yielding the corresponding dimethoxy analogues. 

An interesting approach to the generation of l4C-labeled rivastigmine needed for in vivo studies was published by Novartis (Scheme 11).57 The synthesis of 14C-labeled 2 was initiated by l4C-labeled cyanation of iodide 48 to provide 3-methoxybenzo-14C-nitrile (49) in 80% yield. Copper-mediated addition of methyl magnesium bromide to nitrile 49 formed an imine that was hydrolyzed with aqueous HC1 to the corresponding... 

The synthesis of 14C-labelled / -ureidoisobutyric acid and / -aminoisobutyric acid from thymine using purified enzymes has been carried out earlier148. 

Synthesis of 14C-labelled 5-[1 -hydroxy-2-[2-(o-methoxyphenoxy)-ethylamino]ethyl]-2-methylbenzenesulphonamide hydrochloride (YM-09538)... 

Chen, M. J., and Meister, J. J. (1999). Synthesis of 14C-labelled 1-ethenylbenzene using Wittig reaction and synthesis of graft copolymer of lignin and 14C-labelled 1-ethenylbenzene. i4CS mpos/um Series, pp. 321-330. 

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