1-(3-Chloro-4-fluoro-phen-yl)-5-(2-diazo-acet-yl)-4-phenyl-pyrrolidin-2-one.

In the title compound, C(18)H(13)ClFN(3)O(2), the pyrrolidine ring adopts an envelope conformation and the planar part is rotated by 4.3 (6)° from the plane of the benzene ring and is almost perperdicular both to the diazo-acetyl unit [dihedral angle = 78.93 (7)°] and the phenyl ring [dihedral angle = 86.07 (7)°]. In the crystal, mol-ecules are linked into a three-dimensional framework by C-H⋯O inter-actions. The mol-ecular conformation is stabilized by an intra-molecular C-H⋯O hydrogen bond.

Diethyl 1-(4-methyl-phen-yl)-3-phenyl-5-oxopyrrolidine-2,2-dicarboxyl-ate.

In the title compound, C(23)H(25)NO(5), the lactam ring adopts an envelope conformation and both eth-oxy-carbonyl side chains show an s-cis conformation: one is nearly planar, the dihedral angle between CO(2) and OCH(2)CH(3) groups being 7.95 (14)° and the other is almost orthogonal, the C-O-C-C torsion angle being 85.33 (9)°. Dimers related by inversion symmetry are stabilized by C-H⋯O hydrogen bonds. The crystal structure is consolidated by weak intermolecular C-H⋯O inter-actions. Weak intra-molecular inter-actions of the same kind also occur.

Diethyl 1-(4-fluorophenyl)-3-(2-furyl)-5-oxopyrrolidine-2,2-dicarboxylate and diethyl 1-(3,4-dichlorophenyl)-3-(2-furyl)-5-oxopyrrolidine-2,2-dicarboxylate.

The title compounds, C20H20FNO6 and C20H19Cl2NO6, respectively, may exhibit bioactivity. In these compounds, the pyrrolidine ring adopts a conformation intermediate between envelope and half-chair. Only one of the two ethoxycarbonyl side chains is nearly planar. Centrosymmetric pairs are formed, and the crystal structure is stabilized by weak C-H.O hydrogen bonds and van der Waals interactions.