A convenient and inexpensive synthesis of labelled methylmalonic and propionic acids: Application to the synthesis of methyl-d(3)-malonic and of propionic-3,3,3-d(3) acids.

A synthetic route for obtaining highly pure methylmalonic and propionic aci ds labelled at the methyl groups is validated by the preparation of methyl- d(3)-malonic and propionic 3,3,3-d(3) acids. The synthesis involves the alk ylation of the diethyl allylmalonate with iodomethane-d(3), deallylation of the resulting diethyl allylmethyl-d(3)-malonate by treatment with (eta(2)- propene)Ti(O-i-Pr)(2) and hydrolysis. Decarboxylation of the obtained methy l-d(3)-malonic acid affords propionic-3,3,3-d(3) acid.