2557. Coumalic Acid

Nomenclature

CAS number: 500-05-0
2-Oxo-1,2H-pyran-5-carboxylic acid; α-pyrone-5-carboxylic acid.
C6H4O4; mol wt 140.09.
C 51.44%, H 2.88%, O 45.68%.

Description and references

Prepd by heating anhydr malic acid with oleum: v. Pechmann, Ann. 264, 262, 272 (1891); Wiley, Smith, Org. Synth. coll. vol. IV, 201 (1963).

Chemical structure

Properties

Bright yellow prisms from methanol, mp 205-210° (partial decompn). bp120 218°; sublimes partially. Sparingly sol in cold water. Dec by boiling water. Sol in alcohol, glacial acetic acid. Slightly sol in ether, acetone, ethyl acetate. Insol in chloroform, benzene, ligroin.

Derivative

Methyl ester.
C7H6O4; mol wt 154.12.
C 54.55%, H 3.92%, O 41.52%.

Properties

Leaflets from ligroin, mp 73-74°. bp60 178-180°. bp760 250-260°.

Derivative

Ethyl ester.
C8H8O4; mol wt 168.15.
C 57.14%, H 4.80%, O 38.06%.

Properties

Crystals, mp 36°. bp760 262-265°. Distills without decompn.