Synthesis of 2-[^2H]-2-（1-methylalkyl）succinic acids

We describe a specific procedure for the synthesis of deuterium-labelled 2-（1-methylalkyl）succinate established via alkylation of diethyl malonate, Krapcho decarboxylation reaction with D20 and hydrolysis reaction. Two novel compounds, 2-[^2H]-2-ethylsuccinic acid and 2-[^2H]-2-（1-methylhep- tyl）succinic acid were prepared via this synthetic route and characterized by mass spectrometry and ^1H NMR. The results showed that the 2-（1-methylalkyl）succinic acids were deuterated at the β-position, which is considered as an important reaction centre in the anaerobic degradation of n-alkanes.