Synthesis of [131I/123I]-2-[5-(4-iodophenyl)pentyl]oxirane-2- carboxylic acid ethyl ester.

A method is described for the synthesis, purification and radiolabelling of [123I/131I]2-[5-(4-iodophenyl)-pentyl]oxirane-2-carboxylic acid ethyl ester. For the synthesis of this new agent, 5-phenylpentyl bromide (1), synthesized by reacting 5-phenyl-1-pentanol with sodium bromide under acidic conditions, was converted to diethyl 5-phenylpentylmalonate (2), which, on alkaline hydrolysis, yielded ethyl 5-phenylpentylmalonate (3). Ethyl 7-phenyl-2-methyleneheptanoate (4), prepared from the monoester (3), was oxidized with m-chloroperbenzoic acid to yield ethyl 2-(5-phenylpentyl)oxirane-2-carboxylate 5. The method of radiolabelling, based on the thallation of compound (5) and the subsequent treatment with radioiodide, resulted in a regioselective radioiodination with a 54% radiochemical yield.