is conjugate base of unsaturated fatty acid anion isocrotonic acid isocrotonate (2Z)-but-2-enoate (Z)-2-butenoate (Z)-crotonate 85.029 85.08130 A but-2-enoate having a cis- double bond at C-2. C4H5O2 CHEBI:36254 InChI=1S/C4H6O2/c1-2-3-4(5)6/h2-3H,1H3,(H,5,6)/p-1/b3-2- LDHQCZJRKDOVOX-IHWYPQMZSA-M [H]\C(C)=C\C([O-])=O chebi_ontology cis-2-butenoate cis-crotonate but-2-enoate short-chain fatty acid anion