Synthesis, spectral characteristics, and the crystal and molecular structures of 2,3-dimethyl-1-phenyl-4-(N-phthalimido)pyrazolone-5

2,3-Dimethyl-1-phenyl-4-(N-phthalimido)pyrazolone-5 (I) is synthesized and isolated in the form of single crystals. The crystal structure of compound I is determined using X-ray diffraction. The phthalimide and pyrazolone rings in the molecule are not coplanar: the angle between their median planes is 56.4°. The bond lengths in the rings level off, which indicates the delocalization of the electron density. The spectral characteristics (IR and electronic spectra) of molecule I are determined. © 2008 Pleiades Publishing, Ltd.