... fumaric acid esters used to treat psoriasis. Fumaric acidIUPAC name: (E)-Butenedioic acidOther names: trans-1,2-Ethylenedicarboxylic acid,2-Butenedioic acid, trans-butenedioic acid, Allomaleic acid ... , Boletic acid, Donitic acid, Lichenic acidIdentifiers CAS number: 110-17-8ChemSpider: 10197150UNII: 88XHZ13131EC number 203-743-0 KEGG: C00122 NProperties Molecular formula: C4H4O4 ...