Pyruvic acid

Pyruvic acid Pyruvic acid ( acetylformic acid, pyroracemic acid, a-ketopropionic acid, 2-oxopropanoic acid ), b.p. 165 o C, is the simplest keto acid. It may be prepared: 1. By heating tartaric acid alone, or better, with potassium hydrogen sulphate at 210-220 o C. The reaction is believed to take place via the formation of hydroxymaleic acid (shown in below figure 1), which rearranges to oxalacetic acid, (shown in Figure II) This is the best method for preparing pyruvic acid, and it was this method which gave rise to the name pyroracemic acid. 2 Other methods of preparation are the oxidation of lactic (a-hydroxypropionic) acid, the hydro-lysis of a,a-dibromopropionic acid or acetyl cyanide, e.g., CH 3 COCl (KCN) ⟶ CH 3 COCN (H + ) ⟶ CH 3 COCO 2 H A general method of preparing a-keto-acids uses the Claisen condensation between ethyl oxalate and monocarboxylic esters: Pyruvic acid behaves as a ketone and as an acid; it forms a