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Hiraoka, K.; Miyamoto, T.; Baba, S.; Furuta, T.
doi: 10.1002/jlcr.2580180502pmid: N/A
Preparation of deuterium‐labeled rutin by hydrogen exchange reaction under alkaline condition is described. Hydrogens at positions 2′, 5′ and 6′ of rutin were replaced with deuteriums only on heating, while hydrogens at positions 6 and 8 were readily replaced at room temperature. On the basis of these findings rutin‐2′, 5′, 6′, 6, 8‐d5 was first prepared and then treated with alkaline water at room temperature to obtain rutin labeled with deuteriums at positions 2′, 5′ and 6′.
Mercer, J. R.; Wiebe, L. I.; Knaus, E. E.
doi: 10.1002/jlcr.2580180503pmid: N/A
Reaction of isonicotinic (14C) acid hydrazide (1) with the Zinke salt (2) afforded N‐(4‐pyridyl (14C) carbonylimino)pyridinium ylide (3) in 81% chemical yield. Sodium borohydride reduction of 3 gave N‐(4‐pyridyl (14C) carbonylamino) −1,2,3,6‐tetrahydropyridine (4) in 60% chemical yield with a specific activity of 6.17 mCi mM−1. Alternatively reduction of N‐(4‐pyridylcarbonylimino) pyridinium ylide (5) using absolute ethanol and (3H)‐water as solvent yielded N‐ (4‐pyridylcarbonylamino)‐1,2,(3H)3,6‐tetrahydropyridine (9) in 52.6% chemical yield with a specific activity of 1.14 mCi mM−1. N‐4‐Pyridyl(14C)carbonylamino‐1,2,(3H)3,6‐ tetrahydropyridine (10) was similarly prepared by sodium borohydride reduction of 3 using absolute ethanol and (3H)‐water as solvent in 46% chemical yield with specific activities of 1.31 and 5.66 mCi mM−1 respectively for (3H) and (14C).
doi: 10.1002/jlcr.2580180504pmid: N/A
An 88.6% yield of 2,3,5,6‐tetrachloropyridine‐2,6‐14C (8.99 mCi, 14.5 mCi/mmole) was obtained via chlorination of 2,6‐dichloropyridine‐2,6‐14C.
Hasegawa, M.; Ohyabu, S.; Ueda, T.; Yamaguchi, M.
doi: 10.1002/jlcr.2580180505pmid: N/A
The preparation of SQ‐14225‐14C, anti‐hypertensive drug, is described. The starting material, methacrylic acid‐1‐14C, was prepared in a high yield by carbonation of the corresponding Grignard reagent with 14CO2. The final product was obtained from the acid through a four step synthesis with specific activity of 3.20 mCi/mmol. The overall radiochemical yield was 8.0% based on Ba14CO3.
Billinghurst, M. W.; Rempel, S.; Westendorf, B. A.
doi: 10.1002/jlcr.2580180506pmid: N/A
The importance of maintaining a low ratio of stannous ion to albumin molecules in order to obtain a high quality technetium‐99m labelled albumin is demonstrated. It is further shown that the direct preparation of technetium‐99m albumin by reduction of the technetium‐99mm pertechnetate with stannous ion inevitably leads to the contamination of the product with a certain amount of tin colloid which is also labelled with technetium‐99m. It is demonstrated that this can be avoided by utilizing labelling techniques involving the initial formation of other technetium chelates which are less stable than the albumin complex under certain conditions, adding the albumin to that preparation, adjusting the conditions and thus allowing the albumin to become labelled with technetium‐99m via an exchange with the original chelating agent.
Burke, Terrence R.; Pohl, Lance R.
doi: 10.1002/jlcr.2580180507pmid: N/A
Specifically deuterated derivatives of the inhalation anesthetic enflurane (2‐chloro‐1‐(difluoromethoxy)‐1,1,2‐trifluoroethane) have been synthesized by a facile base catalyzed exchange. Tritiated enflurane has also been synthesized by this procedure.
doi: 10.1002/jlcr.2580180508pmid: N/A
The synthesis of (1‐11C)pentane, (1‐11C)nonane, (1‐11C)‐ undecane, 2‐(11 C)methyl‐naphthalene and (11C)methyl‐benzene (toluene) are reported. The hydrocarbons were prepared by the coupling reaction between (11C)methyl iodide and the appropriate lithium organocuprate. Toluene was also labelled by the coupling reaction between phenyllithium and (11C)methyl iodide. The reactions were carried out in ether giving the 11C‐labelled hydrocarbons in radiochemical yields < 90% with short reaction times (3‐13 min). The overall synthetic time from (11C)carbon dioxide was 9–19 min.
Zakrzewski, Sigmund F.; Evans, E. Anthony
doi: 10.1002/jlcr.2580180509pmid: N/A
Tritium labeled 2,4‐diamino‐5‐adamantyl‐6‐methylpyrimidine was prepared by a platinum metal catalyzed tritium exchange for 4 hr at 70°. The crude material was purified on a Sephadex G‐25 column and converted to its water soluble ethanesulfonate salt. The analysis of the purified material revealed that 43% of the tritium was located in the 6‐methyl group and the remainder in the adamantane moiety of the molecule.
Marigo, G.; Boudet, D. Riviere
doi: 10.1002/jlcr.2580180510pmid: N/A
14CH3 labelled ferulic and sinapic acids have been synthesized through an enzymic methylation of caffeic and 5‐hydroxyferulic acids using labelled S‐adenosyl methionine as 14CH3 donor. The methyltransferases involved which were extracted from stems of Poplar catalyse these reactions with a good efficiency. A purification procedure of 14C S‐adenosyl methionine is described which allows the recycling of 14CH3 donor. The yield of the overall process is therefore greatly improved. This method allows the synthesis of products with high specific radioactivity. Les acides férulique et sinapique marqués au 14C sur le groupement méthyle ont été synthétisés par voie enzymatique à partir des acides caféique et 5‐hydroxyférulique en utilisant la S‐adénosyl méthionine radioactive comme donneur de 14CH3. Le biocatalyseur utilisé, la O‐méthyltransférase, est issu de tiges de Peuplier. Dans les conditions optimales de la réaction, cette enzyme est capable d'assurer la formation des deux acides phénoliques avec un rendement intéressant. La mise au point d'un protocole de purification du donneur de 14CH3 permettant sa réutilisation, améliore la rentabilité de ce mode de synthèse dont l'intérět consiste en l'obtention de produits d'activité spécifique élevée.
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