Nicotinic labelled, synthesis

These studies were confirmed by tracer experiments showing that nitrogen of nicotinic acid (formed by Neurospora) is derived from 3-hydroxyanthranilic acid (478). Experiments with doubly labeled tryptophan demonstrate that tryptophan is probably the only source of quinolinic acid in rat metabolism (645) and that carbon atom 3 of tryptophan, the precursor of the carboxyl carbon of 3-hydroxyanthranilic acid, becomes carboxyl carbon in nicotinic acid (310,340,341,373). In vitro studies of the enzymic oxidation of 3-hydroxyanthranilic acid confirm its relationship to quinolinic acid (498) and show that picolinic acid may also form from it (539,540) but nicotinic acid synthesis under... 

E.J. Knust, M.J. Machulla, M. Molls, F-production in a water target with high yields for F-labelling of organic compounds Synthesis of 6-C F]nicotinic acid diethylamide, J. Label. Compds Radiopharm. 19 (1982) 1643-1644. 

E. J. Knust, H.J. Machulla, C. Astfalk, Radiopharmaceuticals V F-Labeling with water target produced fluorine-18—Synthesis and quality control of 6- F-nicotinic acid diethylamide, Radiochem. Radioanal. Lett. 55 (1983) 249-255. 

Y.S. Ding, F. Liang, J.S. Fowler, M.J. Kuhar, F.l. Carroll, Synthesis of [ F]norchloro-fluoroepibatidine and its N-methyl derivative New PET ligands for mapping nicotinic acetylcholine receptors, J. Label. Compds Radiopharm. 39 (1997) 828-832. 

L. Dolci, F. Dolle, H. Valette, F. Vaufrey, C. Fuseau, M. Bottlaender, C. Crouzel, Synthesis of a fluorine-18 labelled derivative of epibatidine for in vivo nicotinic acetylcholine receptor PET imaging, Bioorg. Med. Chem. 7 (1999) 467-479. 

Dolle, F. Valette, H. Bottlaender, M. Hinnen, F. Vaufrey, F. Guenther, I. Crouzel, C. Synthesis of 2-[ F]fluoro-3-[2(5)-2-azetidinylmethoxy]pyridine, a highly potent radioligand for in vivo imaging central nicotinic acetylcholine receptors. J. Label. Compd. Radiopharm. 1998, 41, 451 63. 

Interest in alkaloids of the nicotine group appears to be on the increase. A review has appeared covering tobacco-specific nitrosamines, which may be causative factors in tobacco-related cancers. The solution conformation, and proton, deuterium, carbon-13, and nitrogen-15 n.m.r. spectra of nicotine and its 2- and 4-isomers, have been studied. A new synthesis of nornicotine and nicotine has been described, and a quantitative carbon-13 n.m.r. spectral analysis of nicotine that is labelled at positions 1, 2, and 3 with carbon-13 been presented. The synthesis and mass spectrometry of several structurally related nicotinoids have been reported. Nicotine is dehydrogenated on irradiation in benzene solution in the presence of benzophenone to l -methyl-2 -(3-pyri-dyl)pyrrole. ° Nornicotine has been synthesized in four steps from 3-bromo-pyridine and N-3-butenyl-phthalimide, using a palladium-catalysed vinylic... 

For many groups of compounds of pharmacological interest, a wide variety of labelling procedures are available and indeed two of the earliest compounds to be labelled with carbon-14 were meperidine [5] and morphine [6]. This procedure which involves the reductive alkylation of secondary amines with labelled formaldehyde is still the most widely used method for preparing N-methyl tertiary amines and it has also been used for the synthesis of nicotine [7] and chlorpromazine [8, 9] and, with slight modification, for the preparation of erythromycin [10] and acetylmethadol [11], The reaction of C-methyl iodide has also been used to prepare tertiary amines as in the case of codeine [6] and mepivacaine [12], as well as the tranquillisers, thioridazine [13] and methixene [14]. These examples illustrate that labelling of... 

Roth et al. (196), using C -carboxyl labeled nicotinic acid or nicotinamide, have shown that the compounds are rapidly excreted. A total of about 3% of the carboxyl group was expired as carbon dioxide within 1 day after the injection. A few more per cent is given off as exhaled carbon dioxide several days later. It has been estimated that approximately 15 % of the radioactivity fixed in the tissue is exhaled as carbon dioxide. In later studies it was shown that carbon dioxide production from labeled nicotinic acid and nicotinamide also occurs in hamsters, rats, and dogs (221). Hamsters and rats excrete somewhat more by this route, and the dog very little. This is illustrated in Fig. 10. It is of importance to note that very little of the radioactivity appears in the feces. This may be significant with regard to intestinal synthesis of the vitamin. 

Figure 6.94 Knoevenagel reaction of bifunctional agents on labeled ethyl acetoacetate Application to the synthesis of 4-substituted [4- C]nicotinic acid...

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