Crystal structure of 1′-ethyl­spiro[chroman-4,4′-imidazolidine]-2′,5′-dione: a hydantoine derivative

The title compound, C(13)H(13)N(2)O(3), a hydantoin derivative, crystallized with two mol­ecules (A and B) in an asymmetric unit. In mol­ecule A, the imidazolidine ring is twisted about the C—N bond involving the spiro C atom, while in mol­ecule B this ring is flat (r.m.s. deviation = 0.010 Å). The pyran rings in both mol­ecules have distorted half-chair conformations. The mean plane of the imidazolidine ring is inclined to the aromatic ring of the chroman unit by 79.71 (11)° in mol­ecule A and 82.83 (12)° in mol­ecule B. In the crystal, pairs of N—H⋯O hydrogen bonds link the individual mol­ecules to form A–A and B–B inversion dimers. The dimers are linked via N—H⋯O and C—H⋯O hydrogen bonds, forming sheets lying parallel to the bc plane, viz. (011). Within the sheets, the A and B mol­ecules are linked by C—H⋯π inter­actions.