Ethyl 7-oxo-3,5-diphenyl-1,4-diazepane-2-carboxyl­ate

The title compound, C(20)H(22)N(2)O(3), crystallizes with two independent mol­ecules in the asymmetric unit. In both mol­ecules, the diazepane rings adopt chair conformations. The mean planes of the diazepane rings in the two molecules form dihedral angles of 71.6 (4)/40.3 (5) and 75.9 (5)/58.6 (7)° with the neighbouring benzene rings. The carbonyl-group O atoms deviate significantly from the diazepane rings, by 0.685 (14) and 0.498 (13) Å. The eth­oxy­carbonyl groups show conformational difference between two mol­ecules, as reflected in the orientation of the carbonyl O atoms and the C—C—O—C torsion angle of −179.0 (2)° in one mol­ecule and 73.2 (2)° in the other. In one molecule there is a short N—H⋯O contact that generates an S(5) ring motif. In the crystal, N—H⋯O inter­actions generate R (2) (2)(8) graph-set motifs and C—H⋯O inter­actions generate R (2) (2)(10) and R (2) (2)(14) graph-set motifs. C—H⋯π inter­actions also occur.