Crystal structure of 3-(4-chloro-phen-oxy)-4-(2-nitro-phen-yl)azetidin-2-one with an unknown solvate.

In the title compound, C15H11ClN2O4, the central β-lactam ring is approximately planar [maximum deviation = 0.044 (2) Å for the N atom from the mean plane] and subtends dihedral angles of 61.17 (11) and 40.

Crystal structure of 1-(4-meth-oxy-phen-yl)-4-(4-nitro-phen-yl)-3-phen-oxy-azetidin-2-one.

In the title compound, C22H18N2O5, the central β-lactam ring (r.m.s.