Imazamox: A Quest for Polymorphic Modifications of a Chiral and Racemic Herbicide

The structure–property relationships of new polymorphs of the chiral herbicide imazamox were investigated by X-ray diffraction, hot stage microscopy (HSM), and differential scanning calorimetry (DSC). Four different polymorphs of imazamox­(R) were found. The relationship between different crystal forms, relative thermal stability, and possible conversions pathways was explored. Racemic imazamox, for which no polymorphic modifications could be observed, was also characterized in the solid state.