Preparation of deuterated succinic acids

Succinic [2,3-2H2]- and [2,2,3,3-2H4]-acids were prepared from maleic anhydride and dimethyl fumarate, and acetylene dicarboxylic acid and its dimethyl ester by treatment with Cu-Al and Ni-Al alloys in 10% NaOD-D20 in 95% to 100% isotopic purity. The succinic 2H4 acid having high isotopic purity was also obtained on the hydrolysis of 1,2-ethanedinitrile with alkaline deuterium oxide. Based on the 1H[2H] spectra analysis of N-(o-biphenyl)[2,3-2H2]succinimide, it was elucidated that the Raney alloy reduction with alkaline deuterium oxide proceeds stepwise. (author)