Synthesis, characterization and radiolabelling of 2-[6-(4-bromophenoxy)hexyl]oxirane-2-carboxylic acid

A method is described for the synthesis, purification and radiolabelling of 2-[6-(4-bromophenoxy)hexyl]-oxirane-2-carboxylic acid. For the synthesis of this new agent, 6-(4-bromophenoxy)hexylbromide (1), synthesized by the treatment of 4-bromophenol with 1,6-dibromohexane under basic conditions, was converted to diethyl 6-(4-bromophenoxy)hexylmalonate (2), which, on alkaline hydrolysis, yielded ethyl 6-(4-bromophenoxy)hexylmalonate (3). Ethyl 8-(4-bromophenoxy)-2-methyleneoctanoate (4), prepared from the monoester (3), was oxidized with m-chloroperbenzoic acid to yield ethyl 2-[6-(4-bromophenoxy)-hexyl]oxirane-2-carboxylate (5). The method of radiolabelling, based on the Cu(I)Cl-assisted nucleophilic exchange reaction, resulted in regioselective radiobromination with a 45% radiochemical yield.