3-(4-Bromophenyl)-5-(4-fluorophenyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide was synthesized from reaction of a mixture of (E)-1-(4-bromophenyl)-3-(4-fluorophenyl)prop-2-en-1-one, thiosemicarabzide and two mole equivalents of sodium hydroxide in ethanol under reflux for 3 h. The solid was filtered, dried and recrystallized from dimethylformamide to give colorless crystals of the title compound (Mp 270–271°C) [1, 2].

C-bound H atoms were placed in calculated positions (C—H 0.93 Å) and were included in the refinement in the riding model approximation, with U_iso(H) set to 1.2U_eq(C). The nitrogen-bound H atoms was located on a difference Fourier map and refined freely.

N¹-thiocarbamoyl-3,5-diaryl-4,5-dihydro-(1H)pyrazoles are useful as MAO inhibitors against monoamine oxidases which were isolated and purified from the mitochondrial extracts of rat liver homogenates and human platelets [3]. Corresponding derivatives have antimicrobial and antidepressant activities [4, 5]. In the title compound, C₁₆H₁₃BrFN₃S, the asymmetric unit contains only one independent molecule. The central pyrazolyl ring (N1/N2/C7—C9) makes a dihedral angles of 14.71(2)° and 80.41(3)° with the plane of the bromophenyl ring (C1—C6) and the plane of the fluorophenyl ring (C10—C15), respectively. The packing of the structure shows two weak hydrogen bonds between N3—H1N3⋯F1ⁱ and C15—H15A⋯Br1ⁱⁱ. (symmetry code: (i) x, y, z-1; (ii) −x+1, y+1/2, −z+1/2.

The authors extend their appreciation to the Deanship of Scientific Research and the Research Center, College of Pharmacy, King Saud University for their funding of this research.