The reaction between acetyl-methyl-malonic ester and bromoacetic ester in the presence of magnesium was part of an attempted new method for the synthesis of αβ-dimethyl-glutaconic acid, the object of which was to test a new general method for the preparation of αβγ-trialkyl-glutaconic acids. [Diagram] Various methods for the synthesis of αβγ-trialkyl-glutaconic acids have been tried in the past, but these either do not give satisfactory yields, or are such as not to establish positively the constitution of the product. These methods are discussed.