共查询到20条相似文献,搜索用时 31 毫秒
1.
Jiajun Ye Liang Wang Winnie Deuther‐Conrad Yuanyuan Chen Xiaojun Zhang Jinming Zhang Yiyun Huang Peter Brust Hongmei Jia 《Journal of labelled compounds & radiopharmaceuticals》2019,62(8):425-437
We report the design, synthesis, and evaluation of a new series of benzylpiperazine derivatives as selective σ1 receptor ligands. All seven ligands possessed low nanomolar affinity for σ1 receptors (Ki(σ1) = 0.31‐4.19 nM) and high subtype selectivity (Ki(σ2)/Ki(σ1) = 50‐2448). The fluoroethoxy analogues also exhibited high selectivity toward the vesicular acetylcholine transporter (Ki(VAChT)/Ki(σ1) = 99‐18252). The corresponding radiotracers [18F] 13 , [18F] 14 , and [18F] 16 with high selectivity (Ki(σ2)/Ki(σ1) > 100, Ki(VAChT)/Ki(σ1) > 1000) were prepared in 42% to 55% radiochemical yields (corrected for decay), greater than 99% radiochemical purity (RCP), and molar activity of about 120 GBq/μmol at the end of synthesis (EOS). All three radiotracers showed high initial brain uptake in mouse (8.37‐11.48% ID/g at 2 min), which was not affected by pretreatment with cyclosporine A, suggesting that they are not substrates for permeability‐glycoprotein (P‐gp). Pretreatment with SA4503 or haloperidol resulted in significantly reduced brain uptake (35%‐62% decrease at 30 min). In particular, [18F] 16 displayed high brain‐to‐blood ratios and high in vivo metabolic stability. Although it may not be an optimal neuroimaging agent because of its slow kinetics in the mouse brain, [18F] 16 can serve as a lead compound for further structural modifications to explore new potential radiotracers for σ1 receptors. 相似文献
2.
Rui‐Qin Chen Yan Li Qiu‐Yan Zhang Hong‐Mei Jia Winnie Deuther‐Conrad Dirk Schepmann Jörg Steinbach Peter Brust Bernhard Wünsch Bo‐Li Liu 《Journal of labelled compounds & radiopharmaceuticals》2010,53(9):569-574
We report the synthesis and evaluation of 1′‐(4‐[125I]iodobenzyl)‐3H‐spiro[isobenzofuran‐1,4′‐piperidine] ([125I]Spiro‐I) as a potential SPECT tracer for imaging of σ1 receptors. [125I]Spiro‐I was prepared in 55–65% isolated radiochemical yield, with radiochemical purity of >99%, via iododestannylation of the corresponding tributyltin precursor. In receptor binding studies, Spiro‐I displayed low nanomolar affinity for σ1 receptors (σ1: Ki=2.75±0.12 nM; σ2: Ki=340 nM) and high subtype selectivity (σ2/σ1=124). Biodistribution in mice demonstrated relatively high concentration of radioactivity in organs known to contain σ1 receptors, including the lung, kidney, heart, spleen, and brain. Administration of haloperidol 5 min prior to injection of [125I]Spiro‐I significantly reduced the concentration of radioactivity in the above‐mentioned organs. These findings suggest that the binding of [125I]Spiro‐I to σ1 receptors in vivo is specific. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
3.
《Journal of labelled compounds & radiopharmaceuticals》2005,48(1):31-43
The palladium‐mediated N‐arylation of indoles with 4‐[18F]fluoroiodobenzene as a novel radiolabelling method has been developed. Optimized reaction conditions were elaborated by variation of different catalyst systems (CuI/1,2‐diamines and Pd2(dba)3/phosphine ligands), bases and solvents in the reaction of indole with 4‐[18F]fluoroiodobenzene. Optimized reaction conditions (Pd2(dba)3/(2‐(dicyclohexyl‐phosphino)‐2′‐(N,N‐dimethylamino)‐biphenyl, NaOBut, toluene, 100°C for 20 min) were applied for the synthesis of 18F‐labelled σ2 receptor ligands [18F]‐11 and [18F]‐13 which were obtained in 91 and 84% radiochemical yields, respectively. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
4.
《Journal of labelled compounds & radiopharmaceuticals》2003,46(14):1261-1268
Nicotinic acetylcholine receptors are widely distributed throughout the human brain and are believed to play a role in several neurological and psychiatric disorders. In order to identify an effective PET radioligand for in vivo assessment of the α4β2 subtype of nicotinic receptor, we synthesized [18F]3‐[1‐(3‐fluoropropyl)‐(S)‐pyrrolidin‐2‐ylmethoxy]pyridine (NicFP). The in vitro KD of NicFP was determined to be 1.1 nM, and the log P value obtained by HPLC analysis of the unlabelled standard was found to be 2.2. The radiosynthesis of [18F]NicFP was carried out by a nucleophilic substitution reaction of anhydrous [18F]fluoride and the corresponding mesylate precursor. After purification by HPLC, the radiochemical yield was determined to be 11.3±2.1% and the specific activity was 0.47±0.18 Ci/μmol (EOS, n = 3). The time of synthesis and purification was 99±2 min. The final product was prepared as a sterile saline solution suitable for in vivo use. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
5.
Optimization and synthesis of an 18F‐labeled dopamine D3 receptor ligand using [18F]fluorophenylazocarboxylic tert‐butylester
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Natascha Nebel Simone Maschauer Carsten Hocke Harald Hübner Peter Gmeiner Olaf Prante 《Journal of labelled compounds & radiopharmaceuticals》2016,59(2):48-53
There is still no efficient fluorine‐18‐labeled dopamine D3 subtype selective receptor ligand for studies with positron emission tomography. We aim at improving the D3 selectivity and hydrophilicity of a candidate ligand by changing the substitution pattern to a 2,3‐dichlorophenylpiperazine and hydroxylation of the butyl chain. The compound [18F]3 exhibited D3 affinity of Ki = 3.6 nM, increased subtype selectivity (Ki(D2/D3) = 60), and low affinity to 5‐HT1A and α1 receptors (Ki (5‐HT1A/D3) = 34; Ki (α1/D3) = 100). The two‐step radiosynthesis was optimized for analog [18F]4 by reducing the necessary concentration of the precursor amine (57 mM), which reacted with [18F]fluorophenylazocarboxylic tert‐butylester under basic conditions. The optimization of the base (Cs 2CO3, 23 mM) and the adjustment of reaction temperature led to the radiochemical yield of 63% after 5 min at 35°C. The optimized reaction conditions were transferred on to the synthesis of [18F]3 with an overall non‐decay corrected yield of 8‐12% in a specific activity of 32‐102 GBq/µmol after a total synthesis time of 30‐35 min. This provides a D 3 radioligand candidate with improved attributes concerning selectivity and radiosynthesis for further preclinical studies. 相似文献
6.
《Journal of labelled compounds & radiopharmaceuticals》2002,45(8):687-696
3‐[[4hyphen;(4‐[18F]fluorophenyl)piperazin‐1‐yl] methyl] ‐1H‐pyrrolo[2,3‐b]pyridine, acandidate to image dopamine D4 receptors, was synthesised via electrophilic fluorination of a trimethylstannyl precursor with high specific radioactivity [18F]F2. The precursor was obtained by a facile four‐step synthetic approach; the trimethylstannyl leaving group was introduced by displacement of iodine utilising palladium catalysis and hexamethyldistannane in an inert solvent. The total radiosynthesis time was 50 min, including purification and formulation for injection. Decay corrected radiochemical yield was <1% as calculated from the amount of [18F]F? produced. Specific radioactivity at the end of synthesis was 12.8–16.4 GBq/μmol. Radiochemical purity was 88–92%. Ex vivo studies in rats showed homogeneous distribution of radioactivity within rat brain. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
7.
Synthesis of [18F] 4‐amino‐N‐(3‐chloro‐4‐fluorophenyl)‐N′‐hydroxy‐1,2,5‐oxadiazole‐3‐carboximidamide (IDO5L): a novel potential PET probe for imaging of IDO1 expression
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Xuan Huang Robert J. Gillies Haibin Tian 《Journal of labelled compounds & radiopharmaceuticals》2015,58(4):156-162
To synthesize 18F‐labeled positron emission tomography (PET) ligands, reliable labeling techniques inserting 18F into a target molecule are necessary. The 18F‐fluorobenzene moiety has been widely utilized in the synthesis of 18F‐labeled compounds. The present study utilized [18F]‐labeled aniline as intermediate in [18F]‐radiolabeling chemistry for the facile radiosynthesis of 4‐amino‐N‐(3‐chloro‐4‐fluorophenyl)‐N′‐hydroxy‐1,2,5‐oxadiazole‐3‐carboximidamide ([18F]IDO5L) as indoleamine 2,3‐dioxygenase 1 (IDO1) targeted tracer. IDO5L is a highly potent inhibitor of IDO1 with low nanomolar IC50. [18F]IDO5L was synthesized via coupling [18F]3‐chloro‐4‐fluoroaniline with carboximidamidoyl chloride as a potential PET probe for imaging IDO1 expression. Under the optimized labeling conditions, chemically and radiochemically pure (>98%) [18F]IDO5L was obtained with specific radioactivity ranging from 11 to 15 GBq/µmol at the end of synthesis within ~90 min, and the decay‐corrected radiochemical yield was 18.2 ± 2.1% (n = 4). 相似文献
8.
Pradip Ghosh Juri G. Gelovani Mian M. Alauddin 《Journal of labelled compounds & radiopharmaceuticals》2007,50(13):1185-1191
Radiosyntheses of two N3‐substituted thymidine analogues, N3‐[(4[18F]fluoromethyl‐phenyl)butyl]thymidine ([18F]‐FMPBT) and N3‐[(4[18F]fluoromethyl‐phenyl)pentyl]thymidine ([18F]‐FMPPT), are reported. The precursor compounds 9 and 10 were synthesized in six steps and the standard compounds 13 and 14 were synthesized from these precursors. For radiosynthesis, compounds 9 and 10 were fluorinated with n‐Bu4N[18F] to produce [18F]‐ 11 and [18F]‐ 12 , which by acid hydrolysis yielded [18F]‐ 13 and [18F]‐ 14 , respectively. The crude products were purified by high‐performance liquid chromatography to obtain [18F]‐FMPBT and [18F]‐FMPPT. The average decay‐corrected radiochemical yield for [18F]‐ 13 was 15% in five runs, and that for [18F]‐ 14 was 10% in four runs. The radiochemical purity was >99% and the specific activity was >74 GBq/µmol at the end of synthesis. The synthesis time was 80–90 min from the end of bombardment. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
9.
《Journal of labelled compounds & radiopharmaceuticals》2006,49(1):55-70
Two fluoroethoxy substituted derivatives, namely 2‐[4‐(2‐(2‐fluoroethoxy)phenyl)‐piperazin‐1‐ylmethyl]indole‐5‐carbonitrile ( 5a ) and 2‐[4‐(4‐(2‐fluoroethoxy)‐phenyl)piperazin‐1‐ylmethyl]indole‐5‐carbonitrile ( 5b ) were synthesized as analogs of the selective D4 receptor ligand 2‐[4‐(4‐fluorophenyl)piperazin‐1‐ylmethyl]indole‐5‐carbonitrile (FAUC 316). In vitro characterization using CHO‐cells expressing different dopamine receptor subtypes gave Ki values of 2.1 ( 5a ) and 9.9 nM ( 5b ) for the dopamine D4 subtype and displayed a 420‐fold D4‐selectivity over D2 receptors for 5b . The para‐fluoroethoxy substituted candidate 5b revealed substantially reduced α1 and serotoninergic binding affinities in comparison to the ortho‐fluoroethoxy substituted compound. In order to provide potential positron emission tomography (PET) imaging probes for the dopamine D4 receptor, 18F‐labelling conditions using [18F]fluoroethyl tosylate were optimized and led to radiochemical yields of 81 ± 5% ( [18F]5a ) and 47 ± 4% ( [18F]5b ) (n = 3, decay‐corrected and referred to labelling agent), respectively. Thus, 18F‐fluoroethylation favourably at the para position of the phenylpiperazine moiety of the 5‐cyano‐indole framework proved to be tolerated by D4 receptors and could also be applied to alternative scaffolds in order to develop D4 radioligand candidates for PET with improved D4 receptor affinity and selectivity. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
10.
《Journal of labelled compounds & radiopharmaceuticals》2005,48(8):547-555
The novel sigma‐1 receptor PET radiotracer [18F]1‐(2‐fluoroethyl)‐4‐[(4‐cyanophenoxy)methyl]piperidine ([18F]WLS1.002, [18F]‐2) was synthesized (n=6) by heating the corresponding N‐ethylmesylate precursor in an anhydrous acetonitrile solution containing [18F]fluoride, Kryptofix K222 and potassium carbonate for 15 min. Purification was accomplished by reverse‐phase HPLC methods, providing [18F]‐2 in 59±8% radiochemical yield (EOB), with specific activity of 2.89±0.80 Ci/µmol (EOS) and radiochemical purity of 98.3±2.1%. Rat biodistribution studies revealed relatively high uptake in many organs known to contain sigma‐1 receptors, including the lungs, kidney, heart, spleen, and brain. Good clearance from normal tissues was observed over time. Blocking studies (60 min) demonstrated high (>80%) specific binding of [18F]‐2 in the brain, with reduction also noted in other organs known to express these sites. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
11.
Matthias M. Herth Vasko Kramer Frank Rösch 《Journal of labelled compounds & radiopharmaceuticals》2009,52(6):201-207
5‐HT1A receptors are involved in a variety of psychiatric disorders and in vivo molecular imaging of the 5‐HT1A status represents an important approach to analyze and treat these disorders. We report herein the synthesis of three new fluoroethylated 5‐HT1A ligands (AH1.MZ, AH2.MZ and AH3.MZ) as arylpiperazine derivatives containing a norbornene group. AH1.MZ (Ki= 4.2 nM) and AH2.MZ (Ki=30 nM) showed reasonable in vitro affinities to the 5‐HT1A receptor, whereas AH3.MZ appeared to be non‐affine toward the 5‐HT1A receptor. The receptor profile of AH1.MZ and AH2.MZ showed selectivity within the 5‐HT system. 18F‐labelling via [18F]FETos to [18F]AH1.MZ was carried out in radiochemical yields of >70%. The final formulation of injectable solutions including [18F]FETos synthon synthesis, radiosynthesis and semi‐preparative high‐performance liquid chromatography (HPLC) separation took no longer than 130 min and provided [18F]AH1.MZ with a purity of >98% as indicated by analytical HPLC analyses. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
12.
《Journal of labelled compounds & radiopharmaceuticals》2006,49(14):1247-1258
The recently described selective and potent GlyT2 antagonist, 4‐benzyloxy‐3,5‐dimethoxy‐N‐[(1‐dimethylaminocyclopentyl) methyl]benzamide (IC50=16 nM) provided an important additional tool to further characterize GlyT2 pharmacology. In order to identify an effective PET radioligand for in vivo assessment of the GlyT‐2 transporter, 3‐(3‐[18F]fluoropropoxy)‐4‐(benzyloxy)‐N‐((1‐dimethylaminocyclopentyl) methyl)‐5‐methoxybenzamide ([18F] 3 ), a novel analog of 4‐benzyloxy‐3,5‐dimethoxy‐N‐[(1‐dimethylaminocyclopentyl) methyl]benzamide was synthesized using a one‐pot, two‐step method. The NCA radiofluorination of 1,3‐propanediol di‐p‐tosylate in the presence of K2CO3 and Kryptofix‐222 in acetonitrile gave 81% 3‐[18F]fluoropropyl tosylate, which was subsequently coupled with 4‐benzyloxy‐3‐hydroxy‐5‐methoxy‐N‐[(1‐dimethylaminocyclopentyl) methyl]benzamide in the same reaction vessel. Solvent extraction and HPLC (Eclipse XDB‐C8 column, 80/20/0.1 MeOH/H2O/Et3N, 3.0 ml/min) gave [18F] 3 in 98.5% radiochemical purity. The radiochemical yield was determined to be 14.0–16.2% at EOS, and the specific activity was 1462±342 GBq/µmol. The time of synthesis and purification was 128 min. The final product was prepared as a sterile saline solution suitable for in vivo use. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
13.
Uwe Ackermann Duanne Sigmund Shinn Dee Yeoh Angela Rigopoulos Graeme O'Keefe Glenn Cartwright Jonathan White Andrew M. Scott Henri J. Tochon‐Danguy 《Journal of labelled compounds & radiopharmaceuticals》2011,54(13):788-794
2‐[(4‐[18F]Fluorobenzoyloxy)methyl]‐1,4‐naphthalenedione ([18F]7 ) and 4‐[18F]fluorobenzoic acid ([18F]8 . This coupling reaction was fast and gave quantitative yields. Further investigations are warranted on the use of DCC as a coupling agent in Positron Emission Tomography. The synthesis including HPLC purification and reformulation has been fully automated on a modified FDG synthesiser with two reactor vials. [18F]1 was found to be stable in plasma and saline, but underwent rapid metabolism in a phase 1 metabolite assay using rat S9 liver fractions. An in vivo evaluation of [18F]相似文献
14.
Kazutaka Hayashi Kenji Furutsuka Takehito Ito Masatoshi Muto Hatsumi Aki Toshimitsu Fukumura Kazutoshi Suzuki 《Journal of labelled compounds & radiopharmaceuticals》2012,55(3):120-124
We have developed an efficient synthesis method for the rapid and high‐yield automated synthesis of 4‐(2′‐methoxyphenyl)‐1‐[2′‐(N‐2″‐pyridinyl)‐p‐[18F]fluorobenzamido]ethylpiperazine (p‐[18F]MPPF). No‐carrier‐added [18F]F? was trapped on a small QMA cartridge and eluted with 70% MeCN(aq) (0.4 mL) containing Kryptofix 222 (2.3 mg) and K2CO3 (0.7 mg). The nucleophilic [18F]fluorination was performed with 3 mg of the nitro‐precursor in DMSO (0.4 mL) at 190 °C for 20 min, followed by the preparative HPLC purification (column: COSMOSIL Cholester, Nacalai Tesque, Kyoto, Japan; mobile phase: MeCN/25 mm AcONH4/AcOH = 200/300/0.15; flow rate: 6.0 mL/min) to afford p‐[18F]MPPF (retention time = 9.5 min). p‐[18F]MPPF was obtained automatically with a radiochemical yield of 38.6 ± 5.0% (decay corrected, n = 5), a specific activity of 214.3 ± 21.1 GBq/µmol, and a radiochemical purity of >99% within a total synthesis time of about 55 min. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
15.
《Journal of labelled compounds & radiopharmaceuticals》2002,45(8):647-664
Carboxylic acid derivatives of the amyloid‐binding dye Congo red do not enter the brain well and are thus unable to serve as in vivo amyloid‐imaging agents. A neutral amyloid probe, (E,E)‐1‐(3′,4′‐dihydroxystyryl)‐4‐(3′‐methoxy‐4′‐hydroxystyryl)benzene ( 3 ), devoid of any carboxylate groups has been designed and synthesized via a 12‐step reaction sequence with a total yield of 30%. The unsymmetric compound 3 has also been labelled with C‐11 via [11C]methyl iodide ([11C]CH3I) methylation of a symmetric 4,4′‐dimesyl protected precursor followed by deprotection. Preliminary evaluation indicated that compound 3 selectively stained plaques and neurofibrillary tangles in post‐mortem AD brain, and exhibited good binding affinity (Ki=38±8 nM) for Aβ(1–40) fibrils in vitro. In vivo pharmacokinetic studies indicated that [11C] 3 exhibited higher brain uptake than its carboxylic acid analogs and good clearance from normal control mouse brain. [11C] 3 also exhibited specific in vivo binding to pancreatic amyloid deposits in the NOR‐beta transgenic mouse model. These results justify further investigation of 3 and similar derivatives as surrogate markers for in vivo quantitation of amyloid deposits. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
16.
《Journal of labelled compounds & radiopharmaceuticals》2006,49(2):177-195
To date, some non‐selective β‐adrenoceptor (β‐AR) positron emission tomography (PET) radioligands are in clinical use, but no PET radioligand for the selective imaging of cardiac β1‐ARs is clinically available. Therefore, the aim of this study was to develop a potential high‐affinity PET radioligand for the β1‐subtype of ARs. Here, the synthesis and in vitro evaluation of (S)‐ and (R)‐N‐[2‐[3‐(2‐cyano‐phenoxy)‐2‐hydroxy‐propylamino]‐ethyl]‐N′‐[4‐(2‐fluoro‐ethoxy)‐phenyl]‐urea ( 8a–b ), derivatives of the well‐characterized β1‐AR selective antagonist, ICI 89,406, are described. The (S)‐isomer 8a shows both higher β1‐AR selectivity and β1‐AR affinity than the (R)‐enantiomer 8b (selectivity: 40 800 vs 1580; affinity: KI1=0.049 nM vs KI1=0.297 nM). Therefore, the 18F‐labelled analogue 8e of compound 8a was synthesized. While the direct nucleophilic 18F‐fluorination of the tosylate precursor 8d produced 8e in low radiochemical yields (?2.9% decay‐corrected) and specific activities (?3.5 GBq/µmol at the end of synthesis (EOS), n=9) the alternative two‐step synthesis of 8e from ethylene glycol di‐p‐tosylate 9 , [18F]fluoride ion and phenol precursor 8f gave satisfying results (16.4±3.2% radiochemical yield (decay‐corrected), 99.7±0.5% radiochemical purity, 40±8 GBq/µmol specific activity at the EOS within 174±3 min from the end of bombardment (EOB) (n=5)). Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
17.
《Journal of labelled compounds & radiopharmaceuticals》2004,47(9):531-542
4‐Fluoro‐N‐{2‐[4‐(6‐trifluoromethylpyridin‐2‐yl)piperazin‐1‐yl]ethyl}benzamide is a full 5‐HT1A agonist with high affinity (pKi=9.3), selectivity and a c log P of 3.045. The corresponding PET radioligand 4‐[18F]fluoro‐N‐{2‐[4‐(6‐trifluoromethylpyridin‐2‐yl)piperazin‐1‐yl]ethyl}benzamide was synthesized by nucleophilic aromatic substitution on the nitro precursor. The fluorinating agent K[18F]F/Kryptofix 2.2.2 was both dried (9 min, 700 W) and incorporated in the precursor (5 min, 700 W) using a commercially available microwave oven. In a total synthesis time of 60 min, an overall radiochemical yield of 18% (SD=5, n=7, EOS) was obtained. Radiochemical purity was always higher than 99% and specific activity always higher than 81.4 GBq/µmol (2.2 Ci/µmol). Initial brain uptake in mice was 2.19% ID (5.47% ID/g, 2 min) but decreased rapidly (0.17% ID, 0.45% ID/g (60 min)). During the first 20 min p.i., radioactivity concentration of the brain was significantly higher than that of blood demonstrating good brain entry of the tracer. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
18.
Sean R. Donohue Christer Halldin Magnus Schou Jinsoo Hong Lee Phebus Eyassu Chernet Stephen A. Hitchcock Kevin M. Gardinier Kevin M. Ruley Joseph H. Krushinski John Schaus Victor W. Pike 《Journal of labelled compounds & radiopharmaceuticals》2008,51(3):146-152
PipISB [N‐(4‐fluoro‐benzyl)‐4‐(3‐(piperidin‐1‐yl)‐indole‐1‐sulfonyl)benzamide, 9] was identified as a selective high potency CB1 receptor ligand. Here we describe the labeling of 9 with positron‐emitters to provide candidate radioligands for imaging brain CB1 receptors with positron emission tomography (PET). The radiolabeling of 9 was achieved by two methods, method A with carbon‐11 and method B with fluorine‐18. In method A, [11C]9 was prepared in one step from [11C]carbon monoxide, itself prepared from cyclotron‐produced [11C]carbon dioxide. In method B, [18F]9 was prepared from cyclotron‐produced [18F]fluoride ion in a two‐stage, four‐step synthesis with [18F]4‐fluoro‐benzyl bromide as a labeling agent. The radiosynthesis time for method A was 44 min; decay‐corrected radiochemical yields (RCYs) from [11C]carbon monoxide ranged from 3.1 to 11.6% and specific radioactivities ranged from 21 to 67 GBq/µmol. The radiosynthesis time for method B was 115 min; RCYs from [18F]fluoride ion ranged from 1.5 to 5.6% and specific radioactivities ranged from 200 to 348 GBq/µmol. With these methods, [11C]9 and [18F]9 may be prepared in adequate activity and quality for future evaluation as PET radioligands. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
19.
《Journal of labelled compounds & radiopharmaceuticals》2004,47(7):443-455
The availability of no‐carrier‐added (n.c.a.) 4‐[18F]fluorophenol offers the possibility of introducing the 4‐[18F]fluorophenoxy moiety into potential radiopharmaceuticals. Besides alkyl–aryl ether synthesis using n.c.a. 4‐[18F]fluorophenol the diaryl ether coupling is an attractive synthetic method to enlarge the spectrum of interesting labelling procedures. As examples the syntheses of n.c.a. 2‐(4‐[18F]fluorophenoxy)‐N,N‐dimethylbenzylamine and n.c.a. 2‐(4‐[18F]fluorophenoxy)‐N‐methylbenzylamine were realized by an Ullmann ether synthesis of corresponding 2‐bromobenzoic acid amides using tetrakis(acetonitrile)copper(I) hexafluorophosphate as catalyst and a subsequent reduction of the amides formed. The radiochemical yield of the coupling varied between 5 and 65% based on labelled 4‐[18F]fluorophenol. Both compounds are structural analogues of recently published radiotracers for imaging the serotonin reuptake transporter sites (SERT). However, in vitro binding assays of both molecules showed only a low affinity towards monoamine transporters. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
20.
Elisabeth Blom Farhad Karimi Olof Eriksson Håkan Hall Bengt Långström 《Journal of labelled compounds & radiopharmaceuticals》2008,51(6):277-282
A one‐step 18F‐labelling strategy was used to prepare four 18F‐labelled analogues of 7‐methoxy‐1‐methyl‐9H‐β‐carboline (harmine): 7‐(2‐[18F]fluoroethoxy)‐1‐methyl‐9H‐β‐carboline (5), 7‐(3‐[18F]fluoro‐propoxy)‐1‐methyl‐9H‐β‐carboline (6), 7‐[2‐(2‐[18F]fluoroethoxy)ethoxy]‐1‐methyl‐9H‐β‐carboline (7), and 7‐{2‐[2‐(2‐[18F]fluoroethoxy)ethoxy]‐ethoxy}‐1‐methyl‐9H‐β‐carboline (8). These were synthesized as potential positron emission tomography ligands for monoamine oxidase A (MAO‐A). A solution of pure labelled compound in buffer was obtained in <70 min from end of radionuclide production, with a decay‐corrected yield of up to 23%. The average specific binding to MAO‐A in rat brain, determined by autoradiography experiments, was highest for compounds 7 and 8 (89±2 and 96±1%, respectively), which was obtained at <1 nM radioligand concentration. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献