Synthesis of dopexamine hydrochloride labelled with tritium, deuterium and carbon‐14

Dopexamine hydrochloride labelled with carbon-14 has been prepared by a mixed anhydride reaction between 6-[[2-(3,4-dimethoxyphenyl)ethyl]amino]-6-oxohexanoic acid, ethyl carbonochloridate and 2-phenyl-[1-14C]ethylamine. Deuterium isotopomers have been prepared by exchange, reduction of an unsaturated precursor, and by reductive dehalogenation of a chloro-derivative. Tritium-labelled compound was obtained by acid-catalyzed tritium exchange.