The title compound, C20H27ClN2O3, was obtained via an original synthesis method. The central heterocyclic ring adopts a shallow envelope conformation, with the N atom bearing the cyclo-pentane ring as the flap [deviation from the other atoms = 0.442 (2) Å]. The cyclo-pentane ring adopts a twisted conformation about one of the CN-C bonds: the exocyclic C-N bond adopts an equatorial orientation. The dihedral angles between the central ring (all atoms) and the pendant five- and six-membered rings are 10.3 (2) and 87.76 (14)°, respectively. In the crystal, C-H⋯O inter-actions link the mol-ecules into [011] chains. A weak C-H⋯Cl inter-action links the chains into (100) sheets. A mechanism for the cyclization reaction is proposed.
Keywords: C—H⋯O and C—H⋯O interactions; aziridine rearrangement; crystal structure; synthesis.