Mr. Caira et al., POLYMORPHISM OF N-(2,6-DIOXO-3-PIPERIDYL)PHTHALIMIDE (THALIDOMIDE) - STRUCTURAL CHARACTERIZATION OF A 2ND MONOCLINIC RACEMIC MODIFICATION, Journal of chemical crystallography, 24(1), 1994, pp. 95-99
The X-ray crystal structure of the drug N-(2,6-dioxo-3-piperidyl)pthal
imide (thalidomide), C13H10N2O4, obtained from 1:1 dimethyformamide-et
hanol solution, is reported. This species is monoclinic, space group C
2/c, with a = 20.679(5), b = 8.042(2), c = 14.162(5)angstrom, beta = 1
02.86(3)degrees, Z = 8, R = 0.051 for 1674 unique reflections. Crystal
packing is determined by intermolecular N-H ... O hydrogen bonding wh
ich is more extensive than that reported in the literature for a racem
ate of thalidomide crystallizing in space group P2(1)/n. Comparison of
the melting behavior and X-ray powder diffractograms of the two racem
ic polymorphs shows that they are distinctly different, allowing easy
identification of these species. By comparing experimental X-ray powde
r patterns with those calculated from single crystal data, it was conc
luded that neither of these polymorphs undergoes a phase change on tri
turation.