Synthesis of 1-(2,4-Dinitrophenyl)-3,5-diphenyl-1H-pyrazol-4-ol via trans-1,3-Diphenyl-2,3-epoxy-1-propanone

Abstract

The trans-1,3-diphenyl-2,3-epoxy-1-propanone was synthesized from benzaldehyde and 2-bromoacetophenone in 20 min which is more economical. The presence of ethanol and Br in 2-bromoacetophenone facilitated the reaction. The vicinal diaxial coupling constant of trans-1,3-diphenyl-2,3-epoxy-1-propanone was zero, an indication of trans configuration for a rigid 3-membered ring at ~90^o dihedral angle. 1-(2,4-Dinitrophenyl)-3,5-diphenyl-1H-pyrazol-4-ol was synthesized from trans-1,3-diphenyl-2,3-epoxy-1-propanone and 2,4-dinitro phenylhydrazine in glacial CH₃COOH to give 85.5% yield and characterized using FTIR, ¹H, ¹³C NMR, DEPT 135 and MS spectra. The 1-(2,4-dinitrophenyl)-3,5-diphenyl-1H-pyrazol-4-ol can be exploited for unique biological activities and in the synthesis of synthetic fibers.

Keywords:    1-(2,4-dinitrophenyl)-3,5-diphenyl-1H-pyrazol-4-ol, trans-1,3-diphenyl-2,3-epoxy-1-propanone; synthesis; 2,4-dinitro phenylhydrazine