Efficient steps towards the synthesis of novel (phenyl)(1'-aryl-1,5,5'-triphenyl[3,3'-bi-1Hpyrazol]-
4-yl)methanones 4a-e were developed. The procedure starts from 1-(4-benzoyl-1,5-diphenyl-
1H-3-pyrazolyl)-3-phenyl-2-propyn-1-one (2) which was synthesized by a palladium catalyzed crosscoupling
reaction. Compound 2 reacted with various hydrazines to give (E)-(phenyl)[1,5-diphenyl-3-
[3-phenyl-1-(2-arylhydrazono)-2-propyn-1-yl]-1H-4-pyrazolyl]methanones E-3a-e. The bis-pyrazole
derivatives 4a-e were synthesized from electrophilic cyclization reaction of α,β-acetylenic hydrazones
E-3a-e and copper(I) iodide. All synthesized compounds were characterized by FT-IR, 1H, 13C NMR
and Mass spectral analyses.
Regioselective Synthesis of 3-Haloalkyl-isoxazoles from the Electrophilic Cyclization of Halogenated Oximes