Synthesis of triple [14C]‐labeled moxonidine

The synthesis of radiolabeled antihypertensive compound [2,4,6-14C3]-4-chloro-5-(imidazolidin-2-ylidenimino)-6-methoxy-2-methylpyrimidine ([14C3]moxonidine) was accomplished based on condensation of [1-14C]acetamidine with diethyl [1,3-14C2]malonate to form [2,4,6-14C3]-4,6-dihydroxy-2-methylpyrimidine. Subsequent nitration, chlorination, and hydrogenation gave [2,4,6-14C3]-4,6-dichloro-2-methyl-5-aminopyrimidine. The final product was obtained after the coupling of the above aminopyrimidine with 1-acetylimidazolidin-2-one, followed by hydrolysis using sodium methoxide. Copyright © 2004 John Wiley & Sons, Ltd.