Preparation and crystal structure determination of adducts of copper(II) chloride with 3-aryl-1-(imino-pyridin-2-yl-methyl)-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-pyrazoles

1,1,1-Trifluoro-4-methoxy-4-aryl-but-3-en-2-ones react with 2-pyridylcarboxamidrazone to produce the corresponding 1,1,1-trifluoro-4-aryl-4-(N1-pyridine-2-carboxamidrazone)-3-buten-2-ones. The butenones react with copper(II) chloride to give 1:1 adducts, in which the donor molecules were shown to isomerize to their cyclic pyrazolic forms. The crystal structure of the 4-fluoro-phenyl derivative, dichloro-[3-(4-fluorophenyl)-1-(imino-pyridin-2-yl-methyl)-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-pyrazole]-copper(II), was solved by X-ray crystallography. The structural results are compared with those of other copper(II) chloride adducts of similar ligands containing the amidrazone pharmacophore, which have been tested as anticancer drugs.