Abstract β, β-Dimethylaspartic acid was obtained by the aluminium-amalgam reduction of the O-methyloxime of diethyl 2-oxo-3, 3-dimethyl-1, 4-butanedioate and subsequent hydrolysis. The (latter) diester was conveniently prepared by the condensation of ethyl 2- bromo-2-methylpropionate with diethyl oxalate, under the influence of magnesium. β, β- Difluoroaspartic acid, threo β-methylaspartic acid and β, β-dimethylaspartic acid (as ...