- Preliminary research on 1-(4-bromo-2-nitroimidazol-1-yl)-3-[18F]fluoropropan-2-ol as a novel brain hypoxia PET tracer in a rodent model of stroke
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Abstract The synthesis of the new radiotracer precursor 4-Br-NITTP and the radiolabeling of the new tracer 1-(4-bromo-2-nitroimidazol-1-yl)-3-[18F]fluoropropan-2-ol (4-Br-[18F]FMISO) is reported. The cyclic voltammetry behaviour, neu
- Nieto, Elena,Delgado, Mercedes,Sobrado, Mónica,De Ceballos, María L.,Alajarín, Ramón,García-García, Luis,Kelly, James,Lizasoain, Ignacio,Pozo, Miguel A.,álvarez-Builla, Julio
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- Co(salen)-mediated enantioselective radiofluorination of epoxides. Radiosynthesis of enantiomerically enriched [18F]F-MISO via kinetic resolution
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The first example of transition metal mediated enantioselective radiofluorination of epoxides is reported. The procedure utilizes gaseous [ 18F]HF in a combination with (-)tetramisole and (R,R)-Co(salen), giving the corresponding (S,S)-18F-fluorohydrines in 78-93% radiochemical yield (RCY) and 20-46% enantioselectivities (ee). The use of this methodology allowed for a single step radiosynthesis of [18F]F-MISO, which took 1.5 h and after solid phase-based purification delivered [ 18F]F-MISO in 81%/45% analytical/preparative RCY and 55% ee.
- Revunov, Evgeny,Zhuravlev, Fedor
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- Enantioselective radiosynthesis of positron emission tomography (PET) tracers containing [18F]fluorohydrins
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Herein, we describe an operationally straightforward radiosynthesis of a chiral transition metal fluoride catalyst, [18F](salen)CoF, and its use for late-stage enantioselective aliphatic radiofluorination. We demonstrate the utility of the method by preparing single enantiomer experimental and clinically validated PET tracers that contain base-sensitive functional groups, epimerizable stereocenters, and nitrogen-rich motifs. Unlike the conventional radiosyntheses of these targets with [18F]KF, labeling with (salen)CoF is possible in the last step and under exceptionally mild conditions. These results constitute a rare example of a nucleophilic radiofluorination using a transition metal fluoride and highlight the potential of such reagents to enhance traditional methods for labeling aliphatic hydrocarbons.
- Graham, Thomas J. A.,Lambert, R. Frederick,Ploessl, Karl,Kung, Hank F.,Doyle, Abigail G.
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supporting information
p. 5291 - 5294
(2014/05/06)
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- Biocatalyzed synthesis of both enantiopure fluoromisonidazole antipodes
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Fluoromisonidazole (FMISO or F-MISO) is a radiotracer for positron emission tomography when 18F-labeled and is administrated in its racemic form. Herein, a straightforward synthesis of both enantiopure antipodes is proposed through a one-pot two-step microwave protocol to obtain a fluorinated ketone precursor followed by bioreduction using alcohol dehydrogenases from Rhodococcus ruber (ADH-A) or Lactobacillus brevis (LBADH).
- Borz?cka, Wioleta,Lavandera, Iván,Gotor, Vicente
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supporting information
p. 5022 - 5025
(2013/09/02)
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- Mechanistic investigations of cooperative catalysis in the enantioselective fluorination of epoxides
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This report describes mechanistic studies of the (salen)Co- and amine-cocatalyzed enantioselective ring opening of epoxides by fluoride. The kinetics of the reaction, as determined by in situ 19F NMR analysis, are characterized by apparent first-order dependence on (salen)Co. Substituent effects, nonlinear effects, and reactivity with a linked (salen)Co catalyst provide evidence for a rate-limiting, bimetallic ring-opening step. To account for these divergent data, we propose a mechanism wherein the active nucleophilic fluorine species is a cobalt fluoride that forms a resting-state dimer. Axial ligation of the amine cocatalyst to (salen)Co facilitates dimer dissociation and is the origin of the observed cooperativity. On the basis of these studies, we show that significant improvements in the rates, turnover numbers, and substrate scope of the fluoride ring-opening reactions can be realized through the use of a linked salen framework. Application of this catalyst system to a rapid (5 min) fluorination to generate the unlabeled analog of a known PET tracer, F-MISO, is reported.
- Kalow, Julia A.,Doyle, Abigail G.
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supporting information; experimental part
p. 16001 - 16012
(2011/11/13)
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- Synthesis and characterization of lipophilic 1-[18F]fluoroalkyl-2- nitroimidazoles for imaging hypoxia
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In order to develop new imaging markers for brain hypoxia, two lipophilic nitroimidazoles, 1-(3-fluoropropyl)-2-nitroimidazole (FPN) and 1- (8-fluorooctyl)-2-nitroimidazole (FON) were synthesized and labeled with fluorine-18. The octanol/water partition c
- Yamamoto, Fumihiko,Oka, Hidenobu,Antoku, Shigetoshi,Ichiya, Yu-Ichi,Masuda, Kouji,Maeda, Minoru
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p. 590 - 597
(2007/10/03)
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