Polymorphism of butyrophenones related to haloperidol.

A comparison of X-ray powder diffraction patterns, IR spectra, and crystal structures of structurally related compounds belonging to the butyrophenone family has been undertaken to obtain information about the elements of chemical structure which predispose a substance to exhibit polymorphism. Five butyrophenones, differing by the nature of only one substituent, were selected. After crystallization from 15 solvents, it appears that two compounds of the group exhibit more than one crystalline form.

Conformational study of two polymorphs of spiperone: possible consequences on the interpretation of pharmacological activity.

A second polymorph of spiperone, 8-[3-(p-fluorobenzoyl)-propyl]-1-phenyl-1,3,8-triazaspiro[4,5] decan-4-one, has been isolated and characterized by thermal analysis and IR spectrometry. Its structure was solved by X-ray diffraction analysis. The results are compared with those previously obtained on spiperone, the main difference being in the conformation of the side chain and in the nature of the hydrogen bonding.