Search results for "synthesis"
showing 10 items of 2844 documents
Electrosynthesis of 3,3′,5,5’-tetramethyl-2,2′-biphenol in flow
2020
Abstract3,3′,5,5’-Tetramethyl-2,2′-biphenol is well known as an outstanding building block for ligands in transition-metal catalysis and is therefore of particular industrial interest. The electro-organic method is a powerful, sustainable, and efficient alternative to conventional synthetic approaches to obtain symmetric and non-symmetric biphenols. Here, we report the successive scale-up of the dehydrogenative anodic homocoupling of 2,4-dimethylphenol (4) from laboratory scale to the technically relevant scale in highly modular narrow gap flow electrolysis cells. The electrosynthesis was optimized in a manner that allows it to be easily adopted to different scales such as laboratory, semit…
Synthèse de pinces à fluorures dérivées d'aminoacides pour l'imagerie TEP
2014
This thesis project, which is part of a collaboration between the Institut de Chimie Moléculaire de l’Université de Bourgogne and the Positron Emission Tomography Research Centre, is about the synthesis of fluoride pincers derived from amino acids based on 18F-B bond construction to get a new class of PET imaging agents. First, this project concerned the design, synthesis and characterisation of new boronato and trifluoroborato phosphonium amino acid salts. Quaternisation of o-boronate phenyl phosphine with β-iodo amino esters or γ-iodo amino ester leads to the corresponding salts without racemisation and in yields up to 88%. Saponification of boronato phosphonium amino esters afford the fr…
Synthesis and preliminary evaluation of (R,R)(S,S) 5-(2-(2-[4-(2-[18F]fluoroethoxy)phenyl]-1-methylethylamino)-1-hydroxyethyl)-benzene-1,3-diol ([18F…
2003
The 18 F-labeled b2-adrenergic receptor ligand (R,R)(S,S) 5-(2-(2-(4-(2-( 18 F)fluoroethoxy)phenyl)-1-methylethylamino)-1- hydroxyethyl)-benzene-1,3-diol, a derivative of the original highly selective racemic fenoterol, was synthesized in an overall radio- chemical yield of 20% after 65 min with a radiochemical purity higher than 98%. The specific activity was in the range of 50-60 GBq/mmol. In vitro testing of the non-radioactive fluorinated fenoterol derivative with isolated guinea pig trachea was conducted to obtain an IC50 value of 60 nM. Preliminary ex vivo organ distribution and in vivo experiments with positron emission tomography (PET) on guinea pigs were performed to study the biod…
Improved automated synthesis of [18F]fluoroethylcholine as a radiotracer for cancer imaging.
2007
[(18)F]Fluoroethylcholine has been recently introduced as a promising (18)F-labelled analogue of [(11)C]choline which had been previously described as a tracer for metabolic cancer imaging with positron emission tomography (PET). Due to the practical advantages of using the longer-lived radioisotope (18)F (t(1/2)=110 min), offering the opportunity of a more widespread clinical application, we established a reliable, fully automated synthesis for its production using a modified, commercially available module. [(18)F]Fluoroethylcholine was prepared from N,N-dimethylaminoethanol by iodide catalyzed alkylation with 1-[(18)F]fluoro-2-tosylethane as alkylating agent, resulting in a total radioche…
SYNTHESIS AND IN VITRO AFFINITIES OF VARIOUS MDL 100907 DERIVATIVES AS POTENTIAL 18F-RADIOLIGANDS FOR 5-HT2A RECEPTOR IMAGING WITH PET
2008
Radiolabelled piperidine derivatives such as [(11)C]MDL 100907 and [(18)F]altanserin have played an important role in diagnosing malfunction in the serotonergic neurotransmission. A variety of novel piperidine MDL 100907 derivatives, possible to label with (18)F-fluorine, were synthesized to improve molecular imaging properties of [(11)C]MDL 100907. Their in vitro affinities to a broad spectrum of neuroreceptors and their lipophilicities were determined and compared to the clinically used reference compounds MDL 100907 and altanserin. The novel compounds MA-1 (53) and (R)-MH.MZ (56) show K(i)-values in the nanomolar range towards the 5-HT(2A) receptor and insignificant binding to other 5-HT…
Total synthesis and evaluation of [18F]MHMZ.
2007
Radiochemical labeling of MDL 105725 using the secondary labeling precursor 2-[(18)F]fluoroethyltosylate ([(18)F]FETos) was carried out in yields of approximately 90% synthesizing [(18)F]MHMZ in a specific activity of approximately 50MBq/nmol with a starting activity of approximately 3GBq. Overall radiochemical yield including [(18)F]FETos synthon synthesis, [(18)F]fluoroalkylation and preparing the injectable [(18)F]MHMZ solution was 42% within a synthesis time of approximately 100 min. The novel compound showed excellent specific binding to the 5-HT(2A) receptor (K(i)=9.0 nM) in vitro and promising in vivo characteristics.
Efficient microwave-assisted direct radiosynthesis of [(18)F]PR04.MZ and [(18)F]LBT999: selective dopamine transporter ligands for quantitative molec…
2009
Abstract PR04.MZ 8-(4-fluoro-but-2-ynyl)-3- p -tolyl-8-aza-bicyclo[3.2.1]octane-2-carboxylic acid methyl ester ( 1 ) and LBT999 8-(( E )-4-fluoro-but-2-enyl)-3b- p -tolyl-8-aza-bicyclo[3.2.1]octane-2β-carboxylic acid methyl ester ( 2 ) are selective dopamine reuptake inhibitors, derived from cocaine. Compounds 1 and 2 were labelled with fluorine-18 at their terminally fluorinated N-substituents employing microwave enhanced direct nucleophilic fluorination. K[ 18 F]F − Kryptofix ® 222 cryptate, tetrabutyl ammonium [ 18 F]fluoride and caesium [ 18 F]fluoride were compared as fluoride sources under conventional and microwave enhanced conditions. Fluorination yields were remarkably increased un…
Synthesis of No-Carrier-Added 4-[18F]Fluorophenol from 4-Benzyloxyphenyl-(2-thienyl)iodonium Bromide
2011
4-[(18)F]Fluorophenol is a versatile synthon for the synthesis of more complex radiopharmaceuticals bearing a 4-[(18)F]fluorophenoxy moiety. In order to prepare 4-[(18)F]fluorophenol in no-carrier-added (n.c.a.) form only a nucleophilic labelling method starting from [(18)F]fluoride is suitable. In this paper a new, two step radiosynthesis starting from 4-benzyloxyphenyl-(2-thienyl)iodonium bromide and [(18)F]fluoride with subsequent deprotection is described, yielding n.c.a. [(18)F]fluorophenol in 34 to 36% radiochemical yield.
Fluorescent Hg2+ Sensors: Synthesis and Evaluation of a Tren-Based Starburst Molecule Containing Fluorinated 1,2,4-Oxadiazoles.
2010
A new tren-based starburst molecule containing fluorinated 1,2,4-oxadiazoles as fluorophores has been synthesized and its sensing behavior toward several metal cations has been investigated by UV/Vis, fluorescence, 1 H NMR and 19 F NMR spectroscopy. Selective sensing for Hg 2+ ions through a PET-based mechanism was evidenced, suggesting application as fluorescent sensor for Hg 2+ of the off-on type.
Vegetation and firewood uses in the western Catalan plain from Neolithic to the Middle Age
2011
In this study is presented the synthesis of the results of the anthracological analysis in the western Catalan plain from the Neolithic to the Middle Ages. The data is evaluated in order to provide a preliminary approximation on the development of vegetation and forest exploitation. S. Vila is funded by a FI-DGR 2010 scholarship,granted by the Generalitat de Catalunya (AGAUR), in the framework of the projects HAR2008-05256, and SGR2009-198.