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Journal of Labelled Compounds & Radiopharmaceuticals

Joseph S Wirth, William B Whitman
Dimethylsulfoniopropionate (DMSP, (2-carboxyethyl)dimethylsulfonium) is a highly abundant compound in marine environments. As a precursor to the climatically active gas, dimethylsulfide (DMS), DMSP connects the marine and terrestrial sulfur cycles. However, the fate of DMSP in microbial biomass is not well understood as only a few studies have performed isotopic labeling experiments. A previously published method synthesized 34 S-labeled DMSP from 34 S8 , but the efficiency was only 26 % and required five separate reactions, expensive reagents, and purification of the products of each reaction...
November 14, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Qin Xu, Shumao Zhang, Yan Zhao, Yue Feng, Lin Liu, Liang Cai, Wei Zhang, Zhanwen Huang, Hongyuan Wei, Liangang Zhuo, Yue Chen
The purposes of this study were as follows: 1) to radiolabel ibandronic acid (IBA, a third-generation bisphosphonate) with 177 Lu, investigating optimal labeling conditions; and 2) to analyze biodistribution and imaging properties of intravenous 177 Lu-ibandronate (177 Lu-IBA) administered in animals. 177 Lu-labeled methylene diphosphonate (177 Lu-MDP) served as a comparator agent. Differing proportions of ibandronic acid solution and 177 LuCl3 solution were combined to determine an optimal ratio for radiolabeling purposes, varying pH, temperature, and time to establish ideal reactivity conditions...
November 13, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Robert Hopewell, Karen Ross, Alexey Kostikov, Tharick A Pascoal, Thais Alberti, Monica Lacatus-Samoila, Jean-Paul Soucy, Idriss Bennacef, Eliane Kobayashi, Min Su Kang, Pedro Rosa-Neto, Gassan Massarweh
[18 F]MK-6240 (6-(fluoro)-3-(1H-pyrrolo[2,3-c]pyridin-1-yl)isoquinolin-5-amine) is a highly selective PET radiotracer for the in vivo imaging of neurofibrillary tangles (NFTs). [18 F]MK-6240 was synthesized in one step from its bis-Boc protected precursor N-[(tert-butoxy)carbonyl]-N-(6-nitro-3-[1H-pyrrolo[2,3-c]pyridin-1-yl]isoquinolin-5-yl) carbamate in DMSO using [18 F] fluoride with TEA HCO3 with step-wise heating up to 150 °C, resulting in an isolated radiochemical yield of 9.8% ± 1.8% (n = 3) calculated from the end of bombardment (5...
November 13, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Hanne D Hansen, Cristian C Constantinescu, Olivier Barret, Matthias M Herth, Janus H Magnussen, Szabolcs Lehel, Agnete Dyssegaard, Julie Colomb, Thierry Billard, Luc Zimmer, Gilles Tamagnan, Gitte M Knudsen
So far, no suitable 5-HT7 R radioligand exists for clinical PET imaging. [18 F]2FP3 was first tested in vivo in cats and the results were promising for further evaluations. Here, we evaluate the radioligand in pigs and non-human primates (NHP). Furthermore, we investigate species differences in 5-HT7 R binding with [3 H]SB-269970 autoradiography in post mortem pig, NHP, and human brain tissue. Specific binding of [18 F]2FP3 was investigated by intravenous administration of the 5-HT7 R specific antagonist SB-269970...
November 9, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Takeshi Fuchigami, Noriko Fujimoto, Terushi Haradahira, Yumiko Nojiri, Takashi Okauchi, Jun Maeda, Tetsuya Suhara, Fumihiko Yamamoto, Morio Nakayama, Minoru Maeda, Takahiro Mukai
GluN2B-containing NMDA receptors (NMDARs) play fundamental roles in learning and memory, although they are also associated with various brain disorders. In this study, we synthesized and evaluated three 11 C-labeled N-benzyl amidine derivatives 2-[11 C]methoxybenzyl) cinnamamidine ([11 C]CBA), N-(2-[11 C]methoxybenzyl)-2- naphthamidine ([11 C]NBA) and N-(2-[11 C]methoxybenzyl)quinoline-3-carboxamidine ([11 C]QBA) as PET radioligands for these receptors. The 11 C-benzyl amidines were synthesized via conventional methylation of corresponding des-methyl precursors with [11 C]CH3 I...
October 30, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Bernd Johannsen, P August Schubiger
No abstract text is available yet for this article.
October 29, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Kuo Gai, Baomin Liu, Yinsheng Zhang
Starting from N,N-dimethylamine and D2 O, deuterated fragment of ribociclib was synthesized for use as an mass spectroscopy (MS) internal standard. Furthermore, systematic studies on D0 (unlabeled material) formation during the amidation reaction were performed, leading to the identification of a coupling reagent, HATU (O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate), as main cause. Finally, an alternative route was designed using EDCI/HOBT as coupling reagents to produce the desired deuterated compound without D0 residue...
October 29, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Thomas R Hayes, Charles M Thompson, Joseph E Blecha, John M Gerdes, Henry F VanBrocklin
O-(1-Fluoropropan-2-yl)-O-(4-nitrophenyl) methylphosphonate is a reactive organophosphate ester (OP) developed as a surrogate of the chemical warfare agent sarin that forms a similar covalent adduct at the active site serine of acetylcholinesterase. The radiolabeled O-(1-[18 F]fluoropropan-2-yl)-O-(4-nitrophenyl) methylphosphonate ([18 F] fluorosarin surrogate) has not been previously prepared. In this paper, we report the first radiosynthesis of this tracer from the reaction of bis-(4-nitrophenyl) methylphosphonate with 1-[18 F]fluoro-2-propanol in the presence of DBU...
October 22, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Johannes Toms, Viktor Reshetnikov, Simone Maschauer, Andriy Mokhir, Olaf Prante
The imaging of reactive oxygen species (ROS) at the molecular level with high sensitivity and specificity by PET could be of enormous interest to increase our knowledge about ROS activity and signalling, especially in tumours. The aim of this research was to optimise the click chemistry-based radiosynthesis of an 18 F-labelled aminoferrocene glycoconjugate that was derived from an N-alkylaminoferrocene lead structure known to have anti-cancer activity in vitro. Applying the solvent system phosphate buffer/THF (12/5), Cu (OAc)2 and sodium ascorbate as reducing agent at 60 °C, the alkyne 1 reacted with the 18 F-labelled glycosyl azide [18 F]2 in the presence of carrier 3 (47 μM) to obtain carrier-added [18 F]4 in a radiochemical yield of 85 %...
October 10, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Amy L Vāvere, Kiel D Neumann, Elizabeth R Butch, Bao Hu, Stephen G DiMagno, Scott E Snyder
6-[18 F]Fluorodopamine ([18 F]F-DA) is taken into cells via the norepinephrine transporter (NET). Recent [18 F]F-DA positron emission tomography-computed tomography (PET-CT) imaging of adult neuroendocrine tumors shows a dramatic improvement in sensitivity over the standard-of-care, meta-iodobenzylguanidine (MIBG) single-photon emission computed tomography (SPECT)-CT. A new precursor (ALPdopamine™) allows no-carrier-added synthesis resulting in high-molar activity [18 F]F-DA. Automated synthesis of [18 F]F-DA was performed in a single reactor using a two-step procedure: 1) fluorination via thermolysis of a diaryliodonium salt precursor, followed by 2) acid hydrolysis...
October 5, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Berend Van der Wildt, Bin Shen, Frederick T Chin
[11 C] CO is a highly versatile synthon that allows for labeling at carbonyl positions of many molecules by means of transition metal-mediated carbonylation reactions. The intrinsic complexity of carbonylation reactions often requires tedious screening of reaction conditions for obtaining satisfying yields. Herein, a [11 C] CO dispending system for performing multiple reactions with a single batch of cyclotron-produced [11 C]CO2 is described. This semiautomated setup allows for more rapid and efficient screening of reactions and reaction conditions compared with the traditional "one beam for one reaction" strategy...
October 4, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Volker Derdau, Ken Lawrie
No abstract text is available yet for this article.
October 2, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
M A Motaleb, I T Ibrahim, M O Sarhan, W A Zaghary
A newly synthesized s-triazine derivative 1,1',1"-(((1,3,5-triazine-2,4,6-triyl) tris (azanediyl)) tris (benzene-4,1-diyl))tris (ethan-1-one), (1), was synthesized as a part of an ongoing research for development of novel s-triazine based radiopharmaceuticals. In-vitro cell viability assay against different human cancer cell lines showed very promising inhibitory activity of the synthesized compound. This findings encouraged the radioiodination of 1 to study the degree of its localization in tumor site for evaluating the possibility of its use as a tumor imaging agent...
September 7, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Soumen Das, Anupam Mathur, Navin Sakhare, Madhava B Mallia, H D Sarma, S S Sachdev, A Dash
123 I-Iodophenylpentadecanoic acid (IPPA) is a metabolic agent used in nuclear medicine for diagnosis of myocardial defects. Efforts are underway worldwide to develop a 99m Tc substitute of the above radiopharmaceutical for the aforementioned application. Herein, we report synthesis and biodistribution studies of 99m Tc labeled fatty acids (8, 11 and 15 carbons) obtained via 'click chemistry' for its potential use in myocardial imaging. ω-Bromo fatty acids (8C/11C/15C) were synthetically modified at bromo terminal to introduce a heterocyclic triazole with glycine sidearm in a five step procedure...
September 1, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Brad D Maxwell
The isotopic labeling of molecules for agrichemical and pharmaceutical uses is becoming more challenging as molecules become larger, involve more stereochemistry and as intellectual property rights become more complex. As such, isotope chemists need to continually add new isotopic methods to their armamentarium to successfully label complex molecules with carbon-13 and carbon-14. Recently, there has been a surge in the use of radicals to form new carbon-carbon bonds and for the incorporation of functional groups which can be used to incorporate isotopically labeled carbons...
August 29, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Wulian Chen, Chaomin Zhao, Xiaojun Deng
An efficient and simple synthetic route of deuterium-labeled 2-quinoxalinecarboxylic acid-d4 (QCA-d4 ) and 3-methylquinoxaline-2-carboxylic acid-d4 (MQCA-d4 ) is presented with 99.9% and 99.6% isotopic enrichment using aniline-d5 as labeled starting material. Their chemical structures were confirmed by 1 H NMR, and their isotopic abundance was determined by mass spectrometry analysis.
August 21, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Wangwei Ao, Yuan Li, Yinsheng Zhang
To more accurately and rapidly achieve quantitative detection of clinical crizotinib samples, stable isotope labeled crizotinib was required as an internal standard. We have developed a method to prepare racemic [D9 ] crizotinib using a base-catalyzed H/D exchange of both nitroso compound 2 and the acetophenone compound 6 with D2 O and NaBD4 reduction of 7 as the key steps to introduce the 9 deuterium atoms. Starting with 4-hydroxypiperidine, 14-step synthesis furnished the desired racemic [D9 ] crizotinib 18...
August 17, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Masoumeh Zoghi, Sima Attar Nosrati, Faramarz Rogni, Saaed Rajabifar
The new GnRH-Ιanalogue developed in this paper was based on the D-Trp6 -GnRH-Ι-scaffold, and its potency was increased by the replacement Gly-NH2 by NH-NH2 binding to the Gly at position 10. Triptorelin-Hydrazide analogue was synthesized using solid phase. For 111 In labeling, synthesized peptide was followed by conjugation with DOTA using pSCN-Bn-DOTA. The conjugated Triptorelin-Hydrazide was labeled with 500-550 MBq of 111 In-chloride (in 0.2 M HCl). At optimized conditions after labeling, radio-chromatography showed radiochemical purity of approximately equal to 98% (RTLC) and greater than 95% (HPLC)...
August 14, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Seth Jones, Remo Weck, Annina Burhop, Jens Atzrodt, Volker Derdau
Radiolabelled azidophenyl analogues can make powerful photoaffinity probes for the identification of molecular targets. We describe our efforts to prepare tritiated azidophenyl analogues of the taxols cabazitaxel and docetaxel. Late-stage tritiation by isotope exchange with diiodo precursors resulted in reduction of the azide moiety, which could only be overcome by addition of high excess of a sacrificial azide. Iodine-deuterium exchange experiments on a model system established that deiodination with concomitant azide reduction is a general problem when performing such isotope-exchange reactions on azide-containing aryl iodides...
August 12, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Daniel P Holt, Alvin S Kalinda, Lauren E Bambarger, Sanjay K Jain, Robert F Dannals
In this practitioner protocol, the radiochemical synthesis of [11 C] PABA is described in detail, and a quality control summary of three validation productions is presented. The results indicate that the radiotracer product can be produced in good radiochemical yield (14% at end-of-synthesis (EOS)) at high specific activity (molar activity 11 Ci/μmole EOS; 407 GBq/μmole) and high chemical and radiochemical purity as a sterile, pyrogen-free solution suitable for injection conforming to current Good Manufacturing Practice (cGMP) requirements...
August 8, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
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