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(αS, Z, 1R, 3R)‐[4′,4″‐ 3 H]cyhalothrin and ‐[4″,6′,‐ 3 H]4″‐fluorocyhalothrin: Synthesis of candidate pyrethroid radioligands for the sodium channel
Author(s) -
Latli Bachir,
Greenfield Laura J.,
Casida John E.
Publication year - 1993
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.2580330708
Subject(s) - chemistry , cyhalothrin , pyrethroid , radiochemistry , sodium , stereochemistry , medicinal chemistry , organic chemistry , pesticide , agronomy , biology
(αS,Z,1R,3R)‐Cyhalothrin (1) and (αS,Z,1R,3R)‐4′‐fluorocyhalothrin (2), highly potent insecticides, were selected as candidate radioligands for studies on pyrethroid‐sodium channel interactions. This report describes the synthesis of dihalo derivatives of 1 and 2 and their reductive dehalogenation to the corresponding deuterium‐ and tritium‐labelled pyrethroids. Thus, reduction of 4″,6′‐dibromo‐2 with deuterium gas, platinum oxide and potassium carbonate in ethyl acetate went quantitatively to [4″,6′‐ 2 H]‐2; however, the use of tritium instead of deuterium failed to yield [4″, 6′‐ 3 H]‐2 giving instead decomposed materials. Fortunately the use of the iodo compounds 4″,4′‐diiodo‐1 and 4″,6′‐diiodo‐2 with tritium gas and palladium on carbon in absolute ethanol gave [4″,4′‐ 3 H]‐1 and [4″,6′‐ 3 H]‐2 in near quantitative yields at 55 Ci/mmol.