8021. Pyruvic Acid

Nomenclature

CAS number: 127-17-3
2-Oxopropanoic acid; α-ketopropionic acid; acetylformic acid; pyroracemic acid; brenztraubens"aure (German).
C3H4O3; mol wt 88.06.
C 40.92%, H 4.58%, O 54.51%.

Description and references

Intermediate in sugar metabolism and in enzymatic carbohydrate degradation (alcoholic fermentation) where it is converted to acetaldehyde and CO2 by carboxylase, see Nord, Chem. Rev. 26, 423 (1940). In muscle, pyruvic acid (derived from glycogen) is reduced to lactic acid during exertion, which is reoxidized and partially retransformed to glycogen during rest. The liver can convert pyruvic acid to alanine by amination. Pyruvic acid has been isolated from cane sugar fermentation broth by fixation with β-naphthylamine giving α-methyl-β-naphthocinchonic acid: Grab, Biochem. Z. 123, 84 (1921). The most practical method of preparing pyruvic acid is by distillation of tartaric acid in presence of potassium acid sulfate as dehydrating agent. The distillate must be fractionated under reduced pressure: Erlenmeyer, Ber. 14, 321 (1881); D"obner, Ann. 242, 269 (1887); Howard, Fraser, Org. Synth. coll. vol. I (2nd ed., 1941) p 475. Absorption spectrum: Henri, Fromageot, Bull. Soc. Chim. [4] 37, 846 (1925).

Chemical structure

Properties

Liquid. Odor resembling that of acetic acid. d415 1.267; mp 11.8°; bp760 165° (dec); bp100 106.5°; bp40 85.3°; bp20 70.8°; bp10 57.9°; bp5 45.8°; bp1.0 21.4°; nD20 1.4138. pK (25°) 2.49. Miscible with water, alcohol, ether. Polymerizes and dec on standing unless pure and kept in container with airtight closure.

Derivative

Methyl ester.

Nomenclature

CAS number: 600-22-6
Methyl pyruvate.
C4H6O3; mol wt 102.09.
C 47.06%, H 5.92%, O 47.02%.

Properties

Liquid, bp760 134-137°.

Derivative

Ethyl ester.

Nomenclature

CAS number: 617-35-6
Ethyl methylglyoxylate; ethyl pyruvate.
C5H8O3; mol wt 116.12.
C 51.72%, H 6.94%, O 41.33%.

Properties

Liquid, bp760 155°; bp750 147.5°; bp42 69-71°; bp20 66° also 56°. Prepn from ethyl lactate by oxidation with KMnO4: Cornforth, Org. Synth. coll. vol. IV, 467 (1963).