Time filter

Source Type

Ithaca, NY, United States

Emer E.,University of Oxford | Twilton J.,University of Oxford | Tredwell M.,University of Oxford | Calderwood S.,University of Oxford | And 5 more authors.
Organic Letters | Year: 2014

Arenes substituted with perfluoroalkyl groups are attractive targets for drug and agrochemical development. Exploiting the carbenic character of donor/acceptor diazo compounds, a diversity-oriented synthesis of perfluoroalkylated arenes, for late stage fluorofunctionalization, is described. The reaction of 1-(diazo-2,2,2-trifluoroethyl)arenes with HF, F/Br, F2, CF3H, and CF3SH sources give direct access to a variety of perfluoroalkyl-substituted arenes presenting with incremental fluorine content. The value of this approach is also demonstrated for radiochemistry and positron emission tomography with the [18F]-labeling of CF3CHF-, CF3CBrF-, and CF3CF2-arenes from [18F]fluoride. © 2014 American Chemical Society. Source

Anderson H.,Advion BioSystems | Pillarsetty N.,Sloan Kettering Cancer Center | Cantorias M.,Sloan Kettering Cancer Center | Lewis J.S.,Sloan Kettering Cancer Center
Nuclear Medicine and Biology | Year: 2010

An improved synthesis of 2'-[18F]-fluoro-2'-deoxy-1-β-d-arabinofuranosyl-5-iodouracil ([18F]-FIAU) has been developed. The method utilizes trimethylsilyl trifluoromethanesulfonate (TMSOTf) catalyzed coupling of 2-deoxy-2-[18F]-fluoro-1,3,5-tri-O-benzoyl-d-arabinofuranose with 2,4-bis(trimethylsilyloxy)-5-iodouracil to yield the protected dibenzoyl-[18F]-FIAU. Dibenzoyl-[18F]-FIAU was deprotected with sodium methoxide to yield a mixture of α- andβ-anomers in a ratio of 1:1, which were purified by HPLC. The procedure described in this article eliminates the need for HBr activation of the sugar prior to coupling with silylated iodouracil and is suitable for automation. The total reaction time was about 110 min, starting from [18F]-fluoride. The average isolated yield of the required β-anomer was 10±6% (decay corrected) with average specific activity of 125 mCi/Μmol. © 2010 Elsevier Inc. Source

Huiban M.,Imperial College London | Tredwell M.,University of Oxford | Mizuta S.,University of Oxford | Wan Z.,Glaxosmithkline | And 4 more authors.
Nature Chemistry | Year: 2013

Molecules labelled with the unnatural isotope fluorine-18 are used for positron emission tomography. Currently, this molecular imaging technology is not exploited at its full potential because many 18 F-labelled probes are inaccessible or notoriously difficult to produce. Typical challenges associated with 18 F radiochemistry are the short half-life of 18 F (<2 h), the use of sub-stoichiometric amounts of 18 F, relative to the precursor and other reagents, as well as the limited availability of parent 18 F sources of suitable reactivity ([ 18 F]F - and [ 18 F]F 2). There is a high-priority demand for general methods allowing access to [ 18 F]CF 3 -substituted molecules for application in pharmaceutical discovery programmes. We report the development of a process for the late-stage [ 18 F]trifluoromethylation of (hetero)arenes from [ 18 F]fluoride using commercially available reagents and (hetero)aryl iodides. This [ 18 F]CuCF 3 -based protocol benefits from a large substrate scope and is characterized by its operational simplicity. © 2013 Macmillan Publishers Limited. All rights reserved. Source

Verhoog S.,University of Oxford | Pfeifer L.,University of Oxford | Khotavivattana T.,University of Oxford | Calderwood S.,University of Oxford | And 5 more authors.
Synlett | Year: 2016

We report the synthesis of [18F]arylCF3 and [18F]arylCHF2 derivatives from arylCF2Br and arylCHFCl precursors applying a silver-mediated halogen exchange with [18F]fluoride. In the absence of Ag(I)OTf, no reaction takes place at room temperature for both classes of substrates; this result demonstrates the beneficial role of silver(I) as a means to induce 18F-incorporation under very mild conditions. © Georg Thieme Verlag Stuttgart New York Synlett 2016. Source

Preshlock S.,University of Oxford | Calderwood S.,University of Oxford | Verhoog S.,University of Oxford | Tredwell M.,University of Oxford | And 17 more authors.
Chemical Communications | Year: 2016

[18F]FMTEB, [18F]FPEB, [18F]flumazenil, [18F]DAA1106, [18F]MFBG, [18F]FDOPA, [18F]FMT and [18F]FDA are prepared from the corresponding arylboronic esters and [18F]KF/K222 in the presence of Cu(OTf)2py4. The method was successfully applied using three radiosynthetic platforms, and up to 26 GBq of non-carrier added starting activity of 18F-fluoride. © 2016 The Royal Society of Chemistry. Source

Discover hidden collaborations