2butenoates
2-Butenoates are a class of organic compounds that are esters of 2-butenoic acid. Also known as crotonic acid, 2-butenoic acid is an unsaturated carboxylic acid with the chemical formula C4H6O2. The double bond is located between the second and third carbon atoms, and the carboxyl group is at the first carbon. Because of the double bond, 2-butenoic acid exists as two geometric isomers: cis-2-butenoic acid (also known as angelic acid) and trans-2-butenoic acid (also known as crotonic acid). Consequently, 2-butenoates can be derived from either of these isomers, leading to angelic esters and crotonic esters, respectively.
These compounds are characterized by the presence of the ester functional group (-COO-) attached to a four-carbon