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Trifluoroacetyl as a protecting group for HYNIC: stability in the presence of electrophiles and application in the synthesis of 99mTc-radiolabelled peptides

Bashir-Uddin Surfraz, M., King, R., Mather, S.J., Biagini, S.C.G., Blower, P.J. (2010) Trifluoroacetyl as a protecting group for HYNIC: stability in the presence of electrophiles and application in the synthesis of 99mTc-radiolabelled peptides. Tetrahedron, 66 (11). pp. 2037-2043. ISSN 00404020 (ISSN). (doi:10.1016/j.tet.2010.01.038) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Abstract

TrifluoroacetylHYNIC-peptides have recently been shown to label directly with 99mTc as efficiently as their non-trifluoroacetylated analogs. In this work, the trifluoroacetyl (Tfa) moiety has been evaluated as a protecting group for HYNIC against reaction with strong electrophiles. Fmoc-(trifluoroacetylHYNIC)-lysine, the chosen model starting material, was found to be resistant against acetaldehyde and benzylchloroformate challenges, at 1 mol equiv and a 1000 M excess, respectively. In contrast, the Fmoc-(HYNIC)-lysine derivative, with a free hydrazine group, was quantitatively converted to the corresponding hydrazone after a 1 h incubation with acetaldehyde. Fmoc-(trifluoroacetylHYNIC)-lysine was also found to be stable over a wide pH range (3.6-10) to the acetaldehyde challenge. High efficiency 99mTc-radiolabelling (99%) was achieved in the presence of acetaldehyde using Fmoc-(trifluoroacetylHYNIC)-lysine, as compared to a poor radiolabelling yield (34%) obtained with the non-trifluoroacetylated analog. These findings firmly establish the trifluoroacetyl group as a convenient and effective protecting group for HYNIC, and as a promising alternative to currently available labelling strategies. © 2010 Elsevier Ltd. All rights reserved.

Item Type: Article
DOI/Identification number: 10.1016/j.tet.2010.01.038
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - Tetrahedron [Field not mapped to EPrints] AD - Cancer Research Group, Department of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, United Kingdom [Field not mapped to EPrints] AD - Cancer Research UK, Department of Nuclear Medicine, Dominion House, London, United Kingdom [Field not mapped to EPrints] AD - Functional Materials Group, School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, United Kingdom [Field not mapped to EPrints] AD - Division of Imaging Sciences, King's College London, Guy's Hospital Campus, St Thomas' St., London, SE1 9RT, United Kingdom [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled keywords: 99mTc, HYNIC, Peptide, Protecting group, Trifluoroacetyl, 6 hydrazinonicotinyl, acetaldehyde, electrophile, hydrazine derivative, technetium 99m, trifluoroacetic acid, unclassified drug, article, high performance liquid chromatography, isotope labeling, mass spectrometry, priority journal
Subjects: Q Science > QD Chemistry
R Medicine > R Medicine (General) > R895 Nuclear Medicine
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Giles Tarver
Date Deposited: 21 Jul 2015 10:55 UTC
Last Modified: 29 May 2019 14:52 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/49613 (The current URI for this page, for reference purposes)
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