Crystal Structure of 3-(2'-Hydroxy-5'-methoxyphenyl)-5-(3-methoxy-4-hydroxyphenyl)-4,5-dihydro-1H-pyrazole

Abstract

Pyrazoles are one of the important classes of biologically active compounds.In particular, they are used as antitumor, antibacterial, anti-fungal, anti-parasitic, anti-tubercular and insecticidal agents. 1,2 Some of these compounds also have antiinflammatory, anti-diabetic, anaesthetic and analgesic properties. 3 The synthesis of some of these 3,5-disubstitituted-4,5-dihydro-1H-pyrazoles has already been reported by the condensation of α,β-unsaturated ketones with hydrazine and methyl hydrazine. 4 The investigated compound (Fig. 1), m.p. 173˚C, was characterized by spectral data (IR,UV, NMR, MS) as 3-(2′-hydroxy-5′-methoxy-phenyl)-5-(3-methoxy-4-hydroxyphenyl)-4,5-dihydro-1H-pyrazole. To further confirm the attachment of positions of the hydroxy and methoxy groups on the phenyl rings and to obtain more detailed structural information on the conformation of the molecule in the crystalline state, an X-ray structure determination was carried out; the results are presented here.Crystals suitable for diffraction were prepared by recrystallization from ethanol. All of the hydrogen atoms were found from difference Fourier maps and were refined with isotropic temperature factors.The bond lengths and bond angles of the title compound are comparable to those found in other pyrazole derivatives. It has been reported that the N-N bond length in the pyrazoline ring varies over a wide range, from 1.234 (8)

Synthesis, crystal structure and Hirshfeld surface analysis of 4-[3-(4-hydroxyphenyl)-4,5-dihydro-1H-pyrazol-5-yl]-2-methoxyphenol monohydrate

“…78 (9) . The second structure, 3-(2 0 -hydroxy-5 0 -methoxy-phenyl)-5-(3methoxy-4-hydroxyphenyl)-4,5-dihydro-1H-pyrazole (RES-JUV; Gupta et al, 2006), crystallizes in Pbca with one molecule in the asymmetric unit. The conformation of the pyrazoline ring is the same as that in UJUDOU.…”