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Synthesis of 2‐(5‐(4‐[ 123 I/ 131 I]iodophenyl)pentyl)‐oxirane‐2‐carboxylic acid
Author(s) -
Hafiz Ghulam Abbas,
L. V. Hankes,
L. E. Feinendegen
Publication year - 1990
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.2580280809
Subject(s) - chemistry , moiety , yield (engineering) , hydrolysis , carboxylic acid , carboxylate , ethyl ester , alkaline hydrolysis , medicinal chemistry , organic chemistry , materials science , metallurgy
A method is described for the synthesis, purification and radiolabelling of 2‐{5‐(4‐iodophenyl)pentyl}oxirane‐2‐carboxylic acid (I‐POCA). This new compound was synthesized from 5‐phenyl‐pentylbromide ( 1 ), prepared via 5‐phenyl‐1‐pentanol and subsequently converted to diethyl 5‐phenylpentylmalonate ( 2 ). The latter on alkaline hydrolysis yielded ethyl 5‐phenyl‐pentylmalonate ( 3 ). Para‐substitution of iodine on the phenyl moiety of the monoester ( 3 ) was accomplished by reacting compound ( 3 ) with thallium trifluoroacetate (TTFA) and subsequently with KI. Oxidation of ethyl 7‐(4‐iodophenyl)‐2‐methyleneheptanoate ( 5 ), which was synthesized from the monoester, ethyl 5‐(4‐iodophenyl)pentylmalonate ( 4 ) yielded ethyl 2‐{5‐(4‐iodophenyl)pentyl}oxirane‐2‐carboxylate ( 6 ). The radiolabelling procedure was based on a Cu(I)Cl‐assisted, isotopic exchange reaction, which produced a no‐carrier‐added and regiospecific radioiodination with a 32‐52% radiochemical yield.