carboxylic ester organic molecular entity enoate ester 67.990 68.03090 An alpha,beta-unsaturated carboxylic ester of general formula R(1)R(2)C=CR(3)-C(=O)OR(4) (R(4) =/= H) in which the ester C=O function is conjugated to a C=C double bond at the alpha,beta position. C3O2R4 CHEBI:51702 [*]\C([*])=C(\[*])C(=O)O[*] chebi_ontology enoate enoate esters enoates alpha,beta-unsaturated carboxylic ester olefinic compound