Catalytic deuterium exchange reactions with organics. XXXVIII. Further studies in the labelling of cycloolefins with deuterium chloride

Abstract

A new method for labelling a wide range of cycloolefins (C₅ to C₁₀,) with isotopic hydrogen is described in detail. The method consists of exchange with deuterium chloride or bromide in the presence of acetic acid at temperatures of 130º. The reaction is an addition-elimination process. Under certain conditions with some compounds, isomerization, rearrangement, and polymerization occur as side reactions. The advantages and limitations of the present method for labelling cycloolefins are discussed and compared with conventional procedures such as Wilzbach gas irradiation for tritium and metal-catalysed exchange for both hydrogen isotopes. Possible mechanisms for the reaction are proposed.