N-Butoxycarbonyl-5-oxo-l-proline ethyl ester

The molecular structure of the title compound, C12H19NO5, may be visualized as made up of two nearly perpendicular planes [dihedral angle = 87.39 (12)°] and its crystal structure is a good example of C—H...O interactions assuming significance in optimizing supramolecular aggregation in crystals in a molecule which is severely imbalanced in terms of donors to acceptor atoms. The pyrrolidine ring adopts a (3T2) twist conformation with puckering parameters Q = 0.2630 (4) Å and ϕ = 59 (9)°. The crystal structure features R24(10) and R34(26) ring motifs formed by four weak C—H...O interactions, leading to supramolecular sheets lying parallel to the bc plane