organic molecular entity diethyl malate A maleate ester resulting from the formal condensation of both carboxy groups of maleic acid with ethanol. A colourless liquid at room temperature (m.p. -10degreeC) with boiling point 220degreeC at 1 atm., it is commonly used as a dienophile for Diels-Alder-type cycloaddition reactions in organic synthesis. C8H12O4 CAS:141-05-9 CCOC(=O)C=C/C(=O)OCC PMID:1471155 PMID:1609410 PMID:3341033 diethyl (2Z)-but-2-enedioate