References of "Plenevaux, Alain"
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See detailAsymmetric synthesis of n.c.a. L-[2-11C]-4-chlorophenylalanine.
Plenevaux, Alain ULg; Al-Darwich, M. J.; Lemaire, Christian ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1993), 32

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See detailNon-activated 18F-fluorinated aromatic compounds through nucleophilic substitution and decarbonylation reactions using RhCl[P(C6H5)3]3.
Plenevaux, Alain ULg; Lemaire, Christian ULg; Palmer, A. J. et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1993), 32

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See detailNUCLEOPHILIC ENANTIOSELECTIVE SYNTHESIS OF 6-[F-18]FLUORO-L-DOPA VIA 2 CHIRAL AUXILIARIES
Lemaire, Christian ULg; Plenevaux, Alain ULg; Cantineau, Robert et al

in Applied Radiation & Isotopes (1993), 44(4), 737-744

Asymmetric nucleophilic synthesis of 6-[F-18]fluoro-L-dopa was investigated in order to reach an enantiomeric excess of close to 100% of the L form of this amino acid. The radiochemical synthesis required ... [more ▼]

Asymmetric nucleophilic synthesis of 6-[F-18]fluoro-L-dopa was investigated in order to reach an enantiomeric excess of close to 100% of the L form of this amino acid. The radiochemical synthesis required [F-18]fluoride as fluorinating agent and regioselective nucleophilic substitution of commercially available 6-nitroveratraldehyde. The [F-18]fluorobenzaldehyde thus obtained was easily converted to the corresponding 2-[F-18]fluoro-4,5-dimethoxybenzyl bromide. This alkylating agent was added to the lithium enolates of 1-(S)-(-)camphor imine of t-butyl glycinate (1) and (S)-(-)- 1 -Boc-2-t-butyl-3-methyl-4-imidazolidinone [(S)- Boc-BMI] (2) in order to compare the enantiomeric excess of the L form obtained in each case with these two chiral inductors. The L-isomer of fluorodopa was isolated after H1 hydrolysis and HPLC purification in 5-10% radiochemical yield (decay corrected). The overall synthesis time was of 110 min. Through this synthetic pathway, the L-isomer of fluorodopa was obtained in 83% e.e with 1 and 96% e.e with 2 respectively, as determined by chiral HPLC. A practical three step preparative scale synthesis of 6-[F-19]fluoro-D,L-dopa is also presented. [less ▲]

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See detailSYNTHESIS OF F-18 SUBSTITUTED AROMATIC-ALDEHYDES AND BENZYL BROMIDES, NEW INTERMEDIATES FOR NCA [F-18] FLUORINATION
Lemaire, Christian ULg; Damhaut, Philippe; Plenevaux, Alain ULg et al

in Applied Radiation & Isotopes (1992), 43(4), 485-494

The synthesis of various [F-18]fluoroaromatic aldehydes using activated nitro precursors and aminopolyether supported nucleophilic substitution with F-18(-) is reported. These radiolabelled fluorinated ... [more ▼]

The synthesis of various [F-18]fluoroaromatic aldehydes using activated nitro precursors and aminopolyether supported nucleophilic substitution with F-18(-) is reported. These radiolabelled fluorinated aldehydes (radiochemical yields: 50-75%) are powerful key intermediates leading after treatment with NaBH4 and SOBr2 (SOCl2) to further active intermediates for example substituted [F-18]fluorobenzyl bromides (yields 30-50% EOB). These benzaldehydes and bromides are particularly useful for the preparation of new radiopharmaceuticals (e.g. fluorotroprapride, fluorodexetimide) either by reductive amination or by aromatic N-alkylation. The preparation of various amino acids in D, L (50:50) or enriched L form by asymmetric synthesis is also possible (e.g. L-6-[F-18]fluorodopa, L-4-[F-18]fluoro-m-tyrosine). It can be anticipated that the F-18-labelled fluoroaldehydes will find widespread application in radiopharmaceutical chemistry. [less ▲]

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See detailFeasibility of multumillicurie preparation of L-6-[18F]fluorodopa by nucleophilic asymmetric synthesis.
Lemaire, Christian ULg; Plenevaux, Alain ULg; Comar, D.

in European Journal of Nuclear Medicine (1992), 19

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See detailSYNTHESIS OF NONACTIVATED F-18 FLUORINATED AROMATIC-COMPOUNDS THROUGH NUCLEOPHILIC-SUBSTITUTION AND DECARBOXYLATION REACTIONS
Plenevaux, Alain ULg; Lemaire, Christian ULg; Palmer, Anthtony J. et al

in Applied Radiation & Isotopes (1992), 43(8), 1035-1040

The synthesis of no-carrier-added 3-[F-18]fluoroanisole, 2-[F-18]fluoroanisole, [F-18]fluorobenzene and 4-[F-18]fluoroveratrole are reported. The strategy consists of amino-polyether supported ... [more ▼]

The synthesis of no-carrier-added 3-[F-18]fluoroanisole, 2-[F-18]fluoroanisole, [F-18]fluorobenzene and 4-[F-18]fluoroveratrole are reported. The strategy consists of amino-polyether supported nucleophilic substitution with [F-18]F- on activated nitro aromatic aldehyde precursors followed by decarbonylation using Tris(triphenylphosphine) rhodium (I) chloride. The experimental parameters for this reaction have been studied and optimized with 2-[F-18]fluoro-4-methoxybenzaldehyde and then successfully applied to four other F-18-fluorinated aromatic aldehydes. The decarbonylation yields obtained were 84 +/- 5% (corrected for decay) within 15 min at 150-degrees-C in 1,4-dioxan. [less ▲]

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See detail2- and 4-[18F]fluorotropapride, two specific D2 receptor ligands for positron emission tomography: N.C.A. syntheses and animal studies.
Damhaut, Philippe; Cantineau, Robert; Lemaire, Christian ULg et al

in International Journal of Radiation Applications and Instrumentation. Part A : Applied Radiation and Isotopes (1992), 43(10), 1265-74

Tropapride, (exo)-2,3-dimethoxy-N-[8-(phenylmethyl)-8- azabicyclo[3.2.1]oct-3-yl]benzamide hydrochloride, has been labeled with fluorine-18 at the 2- and 4-positions of its benzylic group. Two synthetic ... [more ▼]

Tropapride, (exo)-2,3-dimethoxy-N-[8-(phenylmethyl)-8- azabicyclo[3.2.1]oct-3-yl]benzamide hydrochloride, has been labeled with fluorine-18 at the 2- and 4-positions of its benzylic group. Two synthetic pathways were investigated: the first one required the alkylation of the norbenzyl precursor with 2- or 4-[18F]fluorobenzyl bromide (radiochemical yield of 5% EOB, 180 min); the second method consisted of a reductive amination of norbenzyl tropapride with 2- or 4-[18F]fluorobenzaldehyde (20% EOB, 110 min). In both cases, the specific activity was found to be greater than 1 Ci/mumol (EOS). Animal studies in rats showed the percentage of the injected dose localizing in the whole brain to be 0.6 +/- 0.09 and 0.2 +/- 0.03 at 2 h post injection for the para- and the ortho-[18F]fluoro analogs of tropapride respectively. Cerebral biodistribution studies showed at 4 h a striatum uptake of 5 +/- 0.7% of the injected dose per gram of striatum for the para derivative with a low fixation into the frontal cortex and the cerebellum (% ID/g FC < 0.4 and % ID/g Cb < 0.3). The selectivity of 4-[18F]fluorotropapride for D2 dopaminergic sites was demonstrated through blocking experiments with ketanserin, spiperone and halopemide. The saturability was confirmed by the use of variable specific activities. These preliminary results showed that 4-[18F]fluorotropapride can be considered as a potent radiopharmaceutical for the study of the dopaminergic system with PET. [less ▲]

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See detailChemical processing for the production of carrier free selenium-73 from germanium and arsenic targets and synthesis of L-[73Se]selenomethionine.
Plenevaux, Alain ULg; Guillaume, M.; Brihaye, C. et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1991), 30

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See detailNCA synthesis of an N-w-[18F]fluoroethyl analog of altanserine, a serotonine S2 receptor ligand.
Lemaire, Christian ULg; Damhaut, Ph.; Cantineau, R. et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1991), 30

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See detailRoutine production and improvement in the purification of 3-N-(2'-[18F]fluoroethyl)spiperone for clinical use.
Plenevaux, Alain ULg; Cantineau, R.; Labar, D. et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1991), 30

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See detailNCA asymmetric synthesis of 6-[18F]fluoro-L-dopa.
Lemaire, Christian ULg; Guillaume, M.; Cantineau, R. et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1991), 30

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See detail18F-substituted aromatic aldehydes, key intermediates for nca radiosyntheses.
Lemaire, Christian ULg; Guillaume, M.; Plenevaux, Alain ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1991), 30

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See detailSynthesis and preliminary animal studies of [131I]iodotropapride: a cerebral dopamine D2 receptor ligand.
Cantineau, R.; Damhaut, Ph.; Plenevaux, Alain ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1991), 30

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See detailAsymmetric synthesis of 4-[18F]fluoro-L-m-tyrosine via aromatic fluorination.
Lemaire, Christian ULg; Damhaut, Ph.; Plenevaux, Alain ULg et al

in Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine (1991), 32

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See detailSerotonine-S2 receptor imaging with [18F]altanserin and PET. Results in young normal controls.
Sadzot, Bernard ULg; Lemaire, Christian ULg; Cantineau, R. et al

in Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine (1991), 32

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See detail4-[18F]Fluorotropapride, a specific D2 receptor ligand for PET.
Damhaut, Ph.; Cantineau, R.; Lemaire, Christian ULg et al

in Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine (1991), 32

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See detail2 and 4-[18F]fluorotropapride, two specific D2 receptor ligand for PET.
Damhaut, Ph.; Cantineau, R.; Lemaire, Christian ULg et al

in European Journal of Nuclear Medicine (1991), 18

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See detailAN APPROACH TO THE ASYMMETRIC-SYNTHESIS OF L-6-[F-18]FLUORODOPA VIA NCA NUCLEOPHILIC FLUORINATION
Lemaire, Christian ULg; Guillaume, Marcel; Cantineau, Robert et al

in Applied Radiation & Isotopes (1991), 42(7), 629-635

The NCA asymmetric synthesis of L-6-[F-18]fluorodopa starting from (1R,2R,5R)-[(+)-2-hydroxypinanyl-3-idene]glycine t-butyl ester as chiral agent has been developed. After F-18-fluorination of the two ... [more ▼]

The NCA asymmetric synthesis of L-6-[F-18]fluorodopa starting from (1R,2R,5R)-[(+)-2-hydroxypinanyl-3-idene]glycine t-butyl ester as chiral agent has been developed. After F-18-fluorination of the two commercially available aldehydes either 6-nitroveratraldehyde or 6-nitropiperonal, the required alkylating [F-18]fluorobenzyl bromide derivative can be easily prepared by treatment with NaBH4 followed by SOBr2. Alkylation of the Schiff base was carried out with the lithium salt of 2,2,6,6-tetramethylpiperidine as base in anhydrous THF at -78-degrees-C. Following hydrolysis of the protecting groups with hydroxylamine and Hl, the L-amino acid was obtained in 75% L form (ee 50%) with a 10% decay corrected (120 min) radiochemical yield. [less ▲]

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See detailThe synthesis of no-carrier-added DL-4-[18F]fluorodeprenyl via the nucleophilic aromatic substitution reaction.
Plenevaux, Alain ULg; Fowler, Joanna S.; Dewey, Stephen L. et al

in International Journal of Radiation Applications and Instrumentation. Part A : Applied Radiation and Isotopes (1991), 42(2), 121-7

No-carrier-added DL-alpha-methyl-beta-4-[18F]fluorophenyl-N-methyl-N-propynylethylamin e (DL-4-[18F]fluorodeprenyl) was synthesized via the following 3-step procedure: (1) nucleophilic aromatic ... [more ▼]

No-carrier-added DL-alpha-methyl-beta-4-[18F]fluorophenyl-N-methyl-N-propynylethylamin e (DL-4-[18F]fluorodeprenyl) was synthesized via the following 3-step procedure: (1) nucleophilic aromatic substitution by [18F]fluoride on 4-nitrobenzaldehyde to produce 4-[18F]fluorobenzaldehyde (yield 65%); (2) the reaction of 4-[18F]fluorobenzaldehyde with (1-chloro-1-(trimethylsilyl)ethyl)lithium followed by hydrolysis to give 4-[18F]fluorophenylacetone (yield 50%); and (3) reductive alkylation of 4-[18F]fluorophenylacetone with N-methyl-propynylamine in the presence of NaBH3CN (yield 35%) followed by HPLC purification to give a racemic mixture of 4-[18F]fluorodeprenyl. The overall yield was 11% (EOB corrected), the synthesis time was 90 min and the specific activity greater than 0.57 Ci/mumol (end of synthesis). This synthesis approach, the conversion of an aromatic aldehyde to a homologous methyl ketone, extends the flexibility of the nucleophilic aromatic substitution reaction by applying it to the synthesis of radiotracers which do not bear electron-withdrawing activating groups on the aromatic ring. The tissue distribution of DL-4-[18F]fluorodeprenyl in mice at 1, 10 and 60 min was also measured and showed that metabolic defluorination was not significant. Clearance of radioactivity from brain after injection of DL-4-[18F]fluorodeprenyl was more rapid than that previously observed for [11C]L-deprenyl. [less ▲]

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See detailFluorine-18-altanserin: a radioligand for the study of serotonin receptors with PET: radiolabeling and in vivo biologic behavior in rats.
Lemaire, Christian ULg; Cantineau, Robert; Guillaume, Marcel et al

in Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine (1991), 32(12), 2266-72

No-carrier-added [18F]altanserin was synthesized by nucleophilic substitution of the corresponding nitro compound with [18F]fluoride in the presence of kryptofix 222 and K2CO3. After purification by ... [more ▼]

No-carrier-added [18F]altanserin was synthesized by nucleophilic substitution of the corresponding nitro compound with [18F]fluoride in the presence of kryptofix 222 and K2CO3. After purification by preparative HPLC, [18F]altanserin was produced in less than 2 hr with a radiochemical yield of 10% (EOS) and a specific activity of 0.8-1.3 Ci/mumol. In rats, the tracer localized rapidly in the whole brain (0.5% ID/g organ) with a high binding to the frontal cortex. The frontal cortex/cerebellum ratio increased with time and reached a plateau of 11 at 2 hr postinjection. This uptake in S2 receptor regions was saturable and could be blocked by pretreatment with various S2 antagonists. This radiopharmaceutical appears to be more selective for S2 receptor sites than other ligands available today and allows the study of S2 receptors under in vivo conditions. [less ▲]

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