Syntheses, Crystal Structures and Antibacterial Activities of Two Antipyrine Derivatives

Two new antipyrine derivatives, 4-{[1-(5-bromo-2-methoxyphenyl) methylidene]amino}-1,5-dimethyl-2-phenyl-2, 3-dihydro-1H-pyrazol-3-one (C19H18BrN3O2, 1) and 4-{[1-(2-hydroxy-3-ethoxyphenyl)methylidene]amino}-1,5-dimethy-2-phenyl-2,3-dihydro-1H-pyrazol-3-one (C20H21N3O3, 2), were synthesized and structurally characterized by elemental analysis, IR and single crystal X-ray diffractions. Compound 1 crystallizes in the monoclinic space group P2(1)/n with unit cell dimensions a = 6.987(1) angstrom, b = 27.930(2) angstrom, c = 9.483(1) angstrom, beta = 109.36(2)degrees, V = 1745.9(4) angstrom(3), Z = 4, R-1 = 0.0430, and wR(2) = 0.0870. Compound 2 crystallizes in the monoclinic space group P2(1)/c with unit cell dimensions a = 19.523(2) angstrom, b = 7.466(1) angstrom, c = 12.954(2) angstrom, beta = 108.797(1)degrees, V = 1787.5(4) angstrom(3), Z = 4, R-1 = 0.0421, and wR(2) = 0.1032. X-ray structure determinations revealed that the molecules of both compounds display trans configurations about the C= N double bonds. In the crystal structures, molecules are linked together by intermolecular C-H center dot center dot center dot O hydrogen bonds. Both compounds show strong antibacterial activities.