Crystal Structures, Vibrational Spectra, and Fungicidal Activity of 1,5-Diaryl-3-oxypyrazoles

The aryloxypyrazole structure is present in a number of bioactive molecules. Four 1,5-diaryl-3-oxypyrazoles containing benzoyl (I), thiazolidinethione (II and III) or per-O-acetylated glucopyranosyl (IV) moieties were characterized by single-crystal X-ray diffraction. Compounds I and II crystallize in a triclinic P-1 system, whereas III and IV crystallize in an orthorhombic Pbca and a monoclinic P21 space groups, respectively. The dihedral angles between the two benzene rings of the pyrazole are 61.33° (I), 62.87° (II), 57.09° (III) and 70.25° (IV). The structures were stabilized by classical intra- (C-H···S for II and III, C-H···O for IV) and intermolecular (C-H···O for I and IV) H-bonds, as well as intermolecular C-H···π stacking interactions. The theoretical FTIR results showed good agreement with the experimental data. Compounds IV, II and III showed moderate fungicidal activity against Sclerotinia sclerotiorum and Gibberella zeae. The structure-activity relationships were discussed.