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Synthesis of tritium labelled thiorphan, an enkephalinase inhibitor
Author(s) -
Wu ShaoYong,
Masjedizadeh Mohammad R.
Publication year - 2009
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.1566
Subject(s) - chemistry , thiorphan , tritium , enkephalinase , catalysis , dithiothreitol , nuclear chemistry , medicinal chemistry , radiochemistry , combinatorial chemistry , organic chemistry , neprilysin , biochemistry , enzyme , enkephalin , physics , receptor , opioid , nuclear physics
Tritium labelling of the enkephalinase inhibitor, thiorphan, is complicated by the presence of mercapto functional group. Reactions often used in aromatic tritiation, such as halogination and catalytic halogen/tritium displacement, are adversely affected by the presence of the divalent sulfur moeity. By protecting the SH group with t ‐butyl group, the tritiation reaction proceeded smoothly without catalyst poisoning. The mercapto functionality was re‐generated with great ease and efficiency using 2‐nitrobenzenesulfenyl chloride and dithiothreitol (DTT). [ 3 H]‐Thiorphan, thus, obtained had a radiochemical purity of >99% by AN‐HPLC and a specific activity of 18.42 Ci/mmol. [ 3 H]‐Thiorphan showed good stability when stored at 4°C in an aqueous solution containing 10% methanol and 0.2% DTT in the dark. Copyright © 2008 John Wiley & Sons, Ltd.