Coumalic acid

Coumalic acid is an organic compound with the molecular formula C6H4O4. Its melting point is around 210 °C.

In laboratory coumalic acid may be obtained by self-condensation of malic acid in fuming sulfuric acid:
 * [[Image:CoumaricAcidSynthesis.png|400px|Coumalic Acid Synthesis]]

Note that this scheme is incorrect. 4 H2O and 2 CO (carbon monoxide, not carbon dioxide) are liberated during the condensation.