Crystal and Molecular Structure of 3-Pyrazolone Derivatives. III. 5-Amino-2-phenyl-4-(9H-thioxanthen-9-yl)-1,2-dihydro-3H-pyrazol-3-one

Abstract

Abstract The crystal and molecular structure of 5-amino-2-phenyl-4-(9H-thioxanthen-9-yl)-1,2-dihydro-3H-pyrazol-3-one has been determined by the X-ray diffraction method to establish the predominant tautomeric form of the 3-pyrazolone ring in the solid state. The title compound, C22H17N3OS, crystallizes in the space group P21⁄c with lattice parameters: a=18.179(4), b=8.333(1), c=11.961(7) Å, β=95.88(3)°, and Z=4. The 5-amino group is intramolecularly hydrogen-bonded to the sulfur atom of the thioxanthene ring (N–H···S=3.284 Å). In the packing structure, molecules are linked to each other through hydrogen bonds between the NH of amino and C=O groups [2.849 Å] and the NH moiety and C=O group [2.939 Å] of the 3-pyrazolone ring.