Synthesis, crystal structure, and fungicidal activity of novel 1,5-Diaryl-1H-pyrazol-3-oxyacetate derivatives

A series of ethyl 2-(1,5-diaryl-1H-pyrazol-3-yloxy)acetate derivatives (5a-5i) have been efficiently synthesized by the reaction of 1,5-diaryl-1H-pyrazol-3-ols (4a-4i) with ethyl 2-bromoacetate. The structures of the newly synthesized compounds were characterized by ¹H NMR spectra and elemental analysis, and the crystal structure of the compound ethyl 2-(5-(4-chlorophenyl)-1-phenyl-1H-pyrazol-3-yloxy)acetate (5c) was determined by single crystal X-ray diffraction analysis. The compound 5c belongs to triclinic system with space group P(-1), a = 5.8170(12) Å, b = 11.804(2) Å, c = 12.783(2) Å, α = 83.89(2)°, β = 89.24(3)°, γ = 89.73(3)°, Formula weight: 356.80, Triclinic V = 872.7(3) ų, D_c = 1.358 mg/m³, Z = 2, F (000) = 372. Bioassay results indicated that the compound ethyl 2-(5-(4-fluorophenyl)-1- phenyl-1H-pyrazol-3-yloxy)acetate (5d) exhibited moderate inhibitory activity against Gibberella zeae at the dosage of 10 μg/mL.