In the title compound, C(7)H(11)NO(4), which is an example of a push-pull alkene, a network of N-H⋯O and C-H⋯O inter-actions helps to establish the crystal structure. The investigated crystal turned out to be a non-merohedral twin with a ratio of twin components of 0.442 (3):0.558 (3). Two pairs of independent mol-ecules (Z' = 4) are linked by inter-molecular N-H⋯O hydrogen bonds, forming independent chains; the chains are connected via inter-molecular C-H⋯O contacts, building a three-dimensional network.