Croconic acid - is a chemical compound with formula C5H2O5 or (C=O)3(COH)2. It has a cyclopentene backbone with two hydroxyl groups adjacent to the double bond and three ketone groups on the remaining carbon atoms. It is sensitive to light, soluble in water and ethanol and forms yellow crystals that decompose at 212 °C.
C 0646 (OTTO) Croconic acid, 98% Cas 488-86-8 - used to prepare 1,3-bis-(2-dimethylamino-5-thienyl)croconine by reacting with dimethyl-thiophen-2-yl-amine. It is also used in organic synthesis and employed as a dye for biological research purposes.