The seven-membered ring in the title compound, C(20)H(19)N(3)O(3), adopts a boat conformation with the two phenyl-ene C atoms representing the stern and the methyl-ene C atom the prow. The dihedral angle between the best plane through the seven-membered ring (r.m.s deviation = 0.358 Å) and the phenyl substituent is 55.8 (1)°. The two rings at either ends of the ethyl chain are staggered [N-CH(2)-CH(2)-N torsion angle = 57.5 (4)°].