Experiments on the synthesis of certain y-ketonic acids closely allied to balbiano's acid Part II Syntheses of alpha beta beta- and alpha alpha beta-trimethylloevulic acids, of the lactone of alpha '-hydroxy-alpha alpha beta-trimethylglutaric acid, and of gamma-Keto-alpha beta beta-trimethylpropane-alpha gamma-dicarboxylic acid (Balbiano's acid)