Ethyl N-diphenylmethyleneglycinate reacts with one equivalent of alkylating agents in the presence of powdered potassium carbonate to afford, after hydrolysis, monoalkylated glycine esters. A similar process using two equivalents of alkylating agents in the presence of powdered potassium hydroxide and a phase transfer catalysts gives, after hydrolysis, dialkylated glycine esters.