Crystal and molecular structure of thalidomide, N-(α-glutarimido)-phthalimide

Crystals of the N-(α-glutarimido)-derivative of phthalimide (Thalidomide), C13H10N2O4, are monoclinic, space group P21/n, with a= 8·233 (1), b= 10·070(2), c= 14·865(2)A, β= 102·53(2)°, and Z= 4. The structure has been determined by direct methods using diffractometer data; full-matrix least-squares refinement has reduced R to 0·053 for 1855 observed reflections, which were corrected for absorption. The phthalimide residue is significantly non-planar, while the glutarimido-moiety approximates a half-chair conformation; the central N–C bond is equatorial. The angle between the mean phthalimide and glutarimido-planes is 81°. Pairs of centrosymmetrically related molecules form hydrogen-bonded dimers through N–H ⋯ O contacts of 2·928 A between glutarimido-residues.